Dopamine D1 and D2 Receptors in Progressive Supranuclear Palsy: An Autoradiographic -Study J. Pascual, MD,"t J. Berciano, MD,S B. Grijalba, MD,* E. del Olmo, MD," A. M. Gontdet, MD,"
J. Figols, MD,S and A. Pazos, MD" Dopamine D1 and D2 receptors were studied in brain tissue sections from a typical patient with progressive supranuclear palsy and in 7 age-matched brains. The density of D1 receptors in the caudate-putamen and frontal cortex of the patient was within control limits. By contrast, the density of nigral D1 receptors and striatal D2 receptors was dramatically reduced in the patient as compared to the control brains. This work shows again that the loss of striatal D2 receptors is the most plausible explanation for the poor response to dopaminergic drugs in patients with progressive supranuclear palsy. While the loss of nigral D1 receptors can be explained by the loss of nigral neurons, it seems that neurons bearing striatal D1 receptors are spared in progressive supranuclear palsy. The clinical effects of selective D l agonists are worth testing in this devastating disorder. Pascual J, Berciano J, Grijalba B, del Olmo E, Gontdet AM, Figols J, Pazos A. Dopamine D1 and D2 receptors in progressive supranuclear palsy: an autoradiographic study. Ann Neurol 1992;32:703-707
the absence of a response to dopaminergic replacement in PSP seems to be the concomitant degeneration of neurons containing dopamine receptors in the striatum. In fact, Bokobta and Ruberg and coworkers reported a reduction of about 50% in 3H-spiperonebinding sites in the caudate-putamen by using membrane homogenates from PSP brains 14, 57. To the best of our knowledge, dopamine D1 receptors have not been examined in PSP. We report here on dopamine D1 and D2 receptor densities in a typical PSP patient, using autoradiographic techniques to study postmortem brain sections.
Patient Report This man was first seen in our hospital in 1983 when he was 64 years old. His medical history was unremarkable. He described an unsteady gait, blurred vision not corrected by glasses, and subtle mental changes. On examination he was mentally slowed, apathetic, and moderately depressed. In addition, lack of voluntary vertical gaze with normal reflex movements, slurred speech, and a rigid-akinetic syndrome were observed. Computed tomography (CT) showed slight brain atrophy. Despite clorimipramine and increasing doses of levodopa plus carbidopa, his symptoms progressed and 2 years later axial rigidity with neck extension, dysphagia, hyperreflexia, complete loss of ocular voluntary movements, and urinary incontinence ensued. CT, performed 3 years after the symptoms began, disclosed progression of the brain atrophy, especially marked in the midbrain. The patient was maintained on levodopa (up to 1 gm daily) plus carbidopa and amitriptyline or trihexyphenidyl with no apparent benefit. H e died suddenly in 1986 while sleeping.
Methods Progressive supranuclear palsy (PSP) is a devastating neurodegenerative disorder characterized by loss of voluntary vertical gaze, dysarthria, subcortical dementia, and dystonic extension of the neck, as well as a rigid-akinetic syndrome 111. Although in its earlier stages PSP can be misdiagnosed as Parkinson's disease (PD), the absence of tremor and the rest of the clinical picture usually allow a correct diagnosis 121. Another important clue for the diagnosis of PSP is the very poor response to levodopa or dopaminergic agonists 131. The nigrostriatal neurons appear to degenerate in patients with PSP as in those with PD. The reason for
From the "Department of Physiology and Pharmacology, Unit of Pharmacology, tDepamnent of Medicine, Service of Neurology, and Section of Neuropathology, University Hospital "Marques de Valdecilla," and Faculty of Medicine, University of Cantabria, Santander, Spain. Received Feb 14, 1992, and in revised form Apr 1 and 27. Accepted for publication May 3, 1992. Address correspondence to Dr Pascual, Service of Neurology, University Hospital "Marqu6s de Valdecdla," 39008 Santander, Spain.
At autopsy, the brain was promptly removed, one half being fixed in 10% formalin for neuropathological examination. The other half was cut into blocks, quickly frozen and stored at - 70°C until it was used in binding assays. Autoradiographic labeling of dopamine D 1 and D2 receptors was performed in several brain regions of the PSP patient (age, 67 years; postmortem delay, 24 hours) as well as in 7 male subjects with no history of neuropsychiatric disease (average age & standard deviation [SD], 69 5 years; postmortem delay & SD, 17 ? 7 hours). For labeling of dopamine D1 receptors and as previously reported 163, we incubated 10-p.m-thick tissue sections with 1 nM 3H-SCH 23390 in 50 mM Tris-hydrochloric acid (HCl), 120 mM sodium chloride (NaCl), 5 mM potassium chloride (KCl), 2 mM calcium chloride (CaCI,), and 1 mM magnesium chloride (MgCI,) @H 7.4) for 75 minutes at room temperature. Adjacent sections were incubated in the same medium in the presence of 10 pM dopamine to determine the nonspecific binding. After incubation, sections were washed for 5 minutes in fresh cold buffer. Labeling of D2 receptors was carried out incubating 10pm-thick caudate-putamen sections for 1 hour in the described Tris-HC1 buffer containing 1 pM ketanserin (to prevent labeling of 5-HT, receptors) and 0.4 nM 3H-spiperone (23.3 Cilmmol). Nonspecific binding was defined by 10 pM
*
Copyright 0 1992 by the American Neurological Association 703
Fig 1 . The zona compacta ofthe substantia nigra showing loss of neurons, gliosis, scattered melanin pigment (arrow), and ballooned neurons. (Hematoxylin-eoszn, x 600.) The insert illustrates a pigmented neuron with neurofibrilla~degeneration. (Hematoxylin-eosin, X 1,500.)
haloperidol. Incubation was terminated by rinsing sections twice for 5 minutes in cold Tris-HCI buffer [7, 83. After washing, for both receptors, sections were quickly dried in a cold-air stream. Autoradiograms were generated by apposing the slide-mounted tissue sections to tritiumsensitive films (3H-Ultrofilm, Leica, Nussloch, Germany) at 4°C for 7 weeks in the case of D 1 receptors and for 10 weeks in the case of D2 receptors. The autoradiograms were analyzed and quantified by using a computer-assisted microdensitometer (Microm IP, Microm Espaiia, Barcelona, Spain). Appropriate standards (Amersham [Buckinghamshire, UKf tritiated microscales), exposed together with the tissues, allowed the transformation of densitometric readings into receptor densities (fmollmg of protein) [9].
l), periaqueductal gray matter, and locus ceruleus. In these brain regions as well as in others, mainly the substantia innominata, dentate nucleus of the cerebellum, and red nucleus, we observed relevant but variably intense gliosis and neuronal loss, with central chromatolysis or granulovacuolar degeneration in the remaining neurons. Slight to moderate gliosis with neither definitive neuronal loss nor neurofibrillary degeneration was observed in the caudate-putamen. Neurochemical Studies These results appear in the Table and are illustrated in Figures 2 and 3. The density of dopamine D1 receptors Density (fmollmg ofprotein) of Dopamine Dl and 0 2 Receptors i n the Progressive Supranuclear Pa& (PSP) Brain as Compared to Control Brains
D1
Results Neuropathological Studies
Macroscopic examination showed generalized brain atrophy most prominent in the midbrain, with an enlarged sylvian aqueduct and third ventricle. Microscopic findings were diagnostic for PSP [lo]. In short, prominent neurofibrillary tangles were seen in the globus pallidus, subthalamic nucleus, substantia nigra (Fig
704 Annals of Neurology
D2
Brain Area
Control
PSP
Control
PSP
Caudate Putamen Substantianigra Frontal cortex
317 +275 +151 +109
325 339 73 122
324 f 58 429 f 69
< 30" < 20"
78
69 40
* 14
~
"Measurementsobtained at three different striatal levels in two separate experiments.
Vol 32 No 5 November 1992
D
C Fig 2. Autoradiographs of D l dopamine receptors as labeled with 3HSCH 23390 in posterior striatum and midbrain sections from control subjects (A, C ) and the patient with pmgressive supranuclear palsy (PSP) {B, D). Note that in PSP striatum (B), Dl receptor densities do not dqfw from control levels (A) in the putamen (P). In adition, D l receptor densities are marked4 reduced in the substantia nigra (SN) of this PSP patient (0)as compared to a control {C).Bar = 2 mm.
in the caudate-putamen and the frontal cortex of the patient was within normal limits as compared to the control group. By contrast, D1 receptors were clearly reduced in the substantia nigra of the patient with PSP in comparison to the control subjects. The density of dopamine D2 receptors was almost negligible in the PSP striatum as compared to control levels. In the human brain, D2 receptors are concentrated over the striatum [7}, but their very low density (< 30-40 fmol/mg of protein) normally in the substantia nigra and neocortex does not allow comparison between the patient and control subjects.
Brief Communication: Pascual et al: D1 and D2 Dopamine Receptors in PSP
705
B
A Pig 3. Autoradiographs of dopamine 0 2 receptors as labeled with 3H-spiperone in anterior striatum sections from control (A) and patient (B) brains. Note that in the patient, 0 2 receptor densities in the caudute (C)-putamen(P) are negiglible, as compared to the control. Bar = 2 mm.
Discussion This is the first report studying dopamine D1 and D2 receptors in PSP by using quantitative autoradiography, thus allowing analysis of the density of these receptors in discrete brain areas. Our study confirms and extends previous findings of a reduction in dopamine D2 receptors in the caudate-putamen of PSP patients 14, 51. In fact, the PSP patient studied here exhibited an almost complete loss of these receptors in both the caudate and the putamen. Dopamine D2 receptors are thought to be located both on dopaminergic nigrostriatal terminals and, perhaps preferably, on large and medium spiny striatal neurons, thus being preserved in pure presynaptic parkinsonian syndromes (8, 11, 121. In our patient, and as is typical in PSP, nigral and striatal degeneration was neuropathologically confirmed, thus correlating with the neurochemical data. Furthermore, D2 downregulation secondary to dopaminergic treatments might partly explain the loss of D2 receptors. Intriguingly, D1 receptors are preserved in the PSP strianun. In the human species, the preservation of D1 receptors in PD, despite the marked nigrostriatal degeneration taking place in this degenerative disorder, strongly suggests a postsynaptic localization of dopamine D1 receptors [12-151. The preservation of dopa-
mine D1 receptors in this patient with PSP, in spite of the important nigral degeneration, also weighs against many D1 receptors being present on nigrostriatal terminals. Recently, it was reported that the neuronal degeneration occurring in PSP striatum is not homogeneous but selective for the large striatal neurons [lGl where D2 and muscarinic receptors are believed to be located [5}. Thus, D1 receptors could be located on one of the several kinds of intrinsic striatal neurons that do not degenerate in this condition. Finally, in theory, as was recently proposed for P-adrenoceptors [17}, dopamine D1 receptors could potentially be located on glial cells, which are known to proliferate in PSP striatum as a result of the striatal neuronal loss. However, lesion models in experimental animals do not lend weight to this hypothesis 1181. Although the loss of nigral D1 receptors in this PSP patient could be explained by the observed neuronal nigral degeneration, the preservation of nigral D1 receptors in patients with PD 112-151 may indicate that the loss of D1 nigral receptors in PSP could be secondary to the degeneration of nigral terminals of gammaaminobutyric acid (GABA)ergic or substance P-containing neurons projecting from the striatum (181. Therefore, our receptor studies in a typical patient with PSP show again that the loss of D2 receptors is the most plausible explanation for the absence of response to dopaminergic drugs. However, the preservation of “postsynaptic” dopamine D 1 receptors indicates that the clinical effects of agonist drugs acting selectively on D1 receptors are worth testing in PSP.
706 Annals of Neurology Vol 32 No 5 November 1992
a hi^ work was supported by grant 852184 from Comisibn Asesora de Investigacion Cientifica y Tecnica (A. P. and J. B.). We are indebted to the neurologists Drs Felix Fernhdez and M. Jose reviewedwho Sedano, the also manuscript. managed this patient. Mr John Hawkins stylistically
1. Steele JC, Richardson JC, Olzewski J. Progressive supranuclear References palsy. Arch Neurol 1964;10:333-359 2. Perkin GD, Lees AJ, Stern GM, Kocen RS. Problems in the diagnosis of progressive supranuclear palsy. J Can Sci Neurol 1978;5:167-173 3. Klawans HL, Ringel SP. Observations on the efficacy of L-dopa in progressive supranuclear palsy. Eur Neurol 1971;5:115-129 4. Bokobza B, Ruberg M, Scatton B, et al. 3H-Spiperone binding, dopamine and HVA concentrations in Parkinson's disease and supranuclear palsy. Eur J Pharmacol 1984;99:167-175 5. Ruberg M, Javoy-Agid F, Hirsch E, et al. Dopaminergic and cholinergic lesions in progressive supranuclear palsy. Ann Neurol 1985;18:523-529 6. Cortks R, Gueye B, Pazos A, et al. Dopamine receptors in human brain: autoradiographic distribution of D, sites. Neuroscience 1989;28:263-273 7. Camps M, Cortes R, Gueye B, et al. Dopamine receptors in human brain: autoradiographic distribution of D, sites. Neuroscience 1989;28:275-290 8. PascualJ, Pazos A, del Olmo E, et al. Presynaptic parkinsonism in olivopontocerebellar atrophy: clinical,pathological and neurochemical evidence. Ann Neurol 1991;30:425-428 9. Unnerstall JR, Niehoff DL, Kuhar MJ, Palacios JM. Quantitative receptor autoradiography using [3H]-Ultrofilm: application of multiple benzodiazepine receptors. J Neurosci Methods 1982;6:59-73 10. Steele JC. Progressive supranuclear palsy. In: Vinken PJ, Bruyn GW, eds. Handbook of clinical neurology, vol22. System disorders and atrophies. Amsterdam: North-Holland, 1975:217-230 11. Guttmann M, Seeman P, Reynolds GP, et al. Dopamine D, receptor density remains constant in treated Parkinson's disease. Ann Neurol 1986;19:487-492 12. Cortes R, Camps M, Gueye B, et al. Dopamine receptors in human brain: autoradiographic distribution of D, and D, sites in Parkinson syndrome of different etiology. Brain Res 1989; 483130-38 13. Pimoule C, Schoemacker H, Reynolds GP, Lager SZ. 3H-SCH 23390 labeled D, receptors are unchanged in schizophrenia and Parkinson's disease. Eur J Pharmacol 1985;114:235-237 14. Raisman R, Cash R, Ruberg M, et al. Binding of 3H-SCH23390 to D, receptors in the putamen of control and parkinsonian subjects. Eur J Pharmacol 1985;113:467-468 15. Rinne JO, Rinne JK, Laakso K, et al. Dopamine D, receptors in the parkinsonian brain. Brain Res 1985;359:306-310 16. Oyanagi K, Takahashi H, Wakabayashi K, Ikuta F. Selective decrease of large neurons in the neostrianun in progressive supranuclear palsy. Brain Res 1988;458:218-223 17. Waeber C, Rig0 M, Chinaglia C, et al. Beta-adrenergic subtypes in the basal g@a of patients with Huntington's chorea and Parkinson's disease. Synapse 1991;8:270-280 18. Creese I, Sibley DR, Hamblin MW, I& SE. The classification of dopamine receptors: relationship to radiohgand binding. Annu Rev Neurosci 1983;6:43-71
SeVeritv Of X-Linked Recessive Bulbospinal Neuronopathy Correlates with Size of the Tandem CAG Repeat in Androgen Keceptor Gene Manabu Doyu, MD,*'F Gen Sobue, MD,* Eiichiro Mukai, MD,S Teruhiko Kachi, MD,§ Takeshi Yasuda, MD," Terunori Mitsuma, MD,* and Akira Takahashi, MD'F The genetic mutation of X-linked recessive bulbospinal neuronopathy is amplification of a polymorphic tandem CAG repeat in the androgen receptor gene. We studied this CAG repeat in 26 Japanese patients from 2 1families with X-linked recessive bulbospinal neuronopathy. The number of CAG repeats was significantly correlated with the age at onset of limb muscular weakness (r = -0.596, p < 0.001) and age-adjusted scored disability (r = 0 . 4 4 6 , ~< 0.03). The length of the CAG repeat therefore seem to be a determinant factor of clinical severity. Doyu M, Sobue G, Mukai E, Kachi T, Yasuda T, Mitsuma T, Takahashi A. Severity of X-linked recessive bulbospinal neuronopathy correlates with size of the tandem CAG repeat in androgen receptor gene. Ann Neurol 1992;32:707-710 X-linked recessive bulbospinal neuronopathy (XBSNP) is an adult form of hereditary motor neuronopathy: The age at onset and severity of muscular weakness and wasting vary among patients El-41, as do the associated endocrine features 12, 3, 51. Androgen receptor (AR) gene mutations show an increased number of a polymorphic tandem CAG repeats in the coding region, which is a specific abnormality in the X-BSNP gene C61. The number of CAG repeats is highly variable in different patients 161. We have analyzed the number of CAG repeats in 26 Japanese patients with X-BSNP, and related this to the severity of muscle wasting and age at onset. From the *Division of Neurology, Fourth Department of Internal Medicine, Aichi Medical University, Nagakute, Aichi; tDepartment of Neurology, Nagoya University School of Medicine, Nagoya; SDepartment of Neurology, National Nagoya Hospital, Nagoya; 5De artment of Neurology, National Chubu Hospital, Obu; and Department of Neurology, Nagoya Daini Red Cross Hospital,
K
Nagoya, Japan. Received Mar 30, 1992, and in revised form May 20. Accepted for publication May 22, 1992. Address correspondence to Dr Sobue, Division of Neurology, Fourth Department of Internal Medicine, Aichi Medical University, Nagakute, Aichi 480-11, Japan.
Copyright 0 1992 by the American Neurological Association 707
J. Figols, MD,S and A. Pazos, MD" Dopamine D1 and D2 receptors were studied in brain tissue sections from a typical patient with progressive supranuclear palsy and in 7 age-matched brains. The density of D1 receptors in the caudate-putamen and frontal cortex of the patient was within control limits. By contrast, the density of nigral D1 receptors and striatal D2 receptors was dramatically reduced in the patient as compared to the control brains. This work shows again that the loss of striatal D2 receptors is the most plausible explanation for the poor response to dopaminergic drugs in patients with progressive supranuclear palsy. While the loss of nigral D1 receptors can be explained by the loss of nigral neurons, it seems that neurons bearing striatal D1 receptors are spared in progressive supranuclear palsy. The clinical effects of selective D l agonists are worth testing in this devastating disorder. Pascual J, Berciano J, Grijalba B, del Olmo E, Gontdet AM, Figols J, Pazos A. Dopamine D1 and D2 receptors in progressive supranuclear palsy: an autoradiographic study. Ann Neurol 1992;32:703-707
the absence of a response to dopaminergic replacement in PSP seems to be the concomitant degeneration of neurons containing dopamine receptors in the striatum. In fact, Bokobta and Ruberg and coworkers reported a reduction of about 50% in 3H-spiperonebinding sites in the caudate-putamen by using membrane homogenates from PSP brains 14, 57. To the best of our knowledge, dopamine D1 receptors have not been examined in PSP. We report here on dopamine D1 and D2 receptor densities in a typical PSP patient, using autoradiographic techniques to study postmortem brain sections.
Patient Report This man was first seen in our hospital in 1983 when he was 64 years old. His medical history was unremarkable. He described an unsteady gait, blurred vision not corrected by glasses, and subtle mental changes. On examination he was mentally slowed, apathetic, and moderately depressed. In addition, lack of voluntary vertical gaze with normal reflex movements, slurred speech, and a rigid-akinetic syndrome were observed. Computed tomography (CT) showed slight brain atrophy. Despite clorimipramine and increasing doses of levodopa plus carbidopa, his symptoms progressed and 2 years later axial rigidity with neck extension, dysphagia, hyperreflexia, complete loss of ocular voluntary movements, and urinary incontinence ensued. CT, performed 3 years after the symptoms began, disclosed progression of the brain atrophy, especially marked in the midbrain. The patient was maintained on levodopa (up to 1 gm daily) plus carbidopa and amitriptyline or trihexyphenidyl with no apparent benefit. H e died suddenly in 1986 while sleeping.
Methods Progressive supranuclear palsy (PSP) is a devastating neurodegenerative disorder characterized by loss of voluntary vertical gaze, dysarthria, subcortical dementia, and dystonic extension of the neck, as well as a rigid-akinetic syndrome 111. Although in its earlier stages PSP can be misdiagnosed as Parkinson's disease (PD), the absence of tremor and the rest of the clinical picture usually allow a correct diagnosis 121. Another important clue for the diagnosis of PSP is the very poor response to levodopa or dopaminergic agonists 131. The nigrostriatal neurons appear to degenerate in patients with PSP as in those with PD. The reason for
From the "Department of Physiology and Pharmacology, Unit of Pharmacology, tDepamnent of Medicine, Service of Neurology, and Section of Neuropathology, University Hospital "Marques de Valdecilla," and Faculty of Medicine, University of Cantabria, Santander, Spain. Received Feb 14, 1992, and in revised form Apr 1 and 27. Accepted for publication May 3, 1992. Address correspondence to Dr Pascual, Service of Neurology, University Hospital "Marqu6s de Valdecdla," 39008 Santander, Spain.
At autopsy, the brain was promptly removed, one half being fixed in 10% formalin for neuropathological examination. The other half was cut into blocks, quickly frozen and stored at - 70°C until it was used in binding assays. Autoradiographic labeling of dopamine D 1 and D2 receptors was performed in several brain regions of the PSP patient (age, 67 years; postmortem delay, 24 hours) as well as in 7 male subjects with no history of neuropsychiatric disease (average age & standard deviation [SD], 69 5 years; postmortem delay & SD, 17 ? 7 hours). For labeling of dopamine D1 receptors and as previously reported 163, we incubated 10-p.m-thick tissue sections with 1 nM 3H-SCH 23390 in 50 mM Tris-hydrochloric acid (HCl), 120 mM sodium chloride (NaCl), 5 mM potassium chloride (KCl), 2 mM calcium chloride (CaCI,), and 1 mM magnesium chloride (MgCI,) @H 7.4) for 75 minutes at room temperature. Adjacent sections were incubated in the same medium in the presence of 10 pM dopamine to determine the nonspecific binding. After incubation, sections were washed for 5 minutes in fresh cold buffer. Labeling of D2 receptors was carried out incubating 10pm-thick caudate-putamen sections for 1 hour in the described Tris-HC1 buffer containing 1 pM ketanserin (to prevent labeling of 5-HT, receptors) and 0.4 nM 3H-spiperone (23.3 Cilmmol). Nonspecific binding was defined by 10 pM
*
Copyright 0 1992 by the American Neurological Association 703
Fig 1 . The zona compacta ofthe substantia nigra showing loss of neurons, gliosis, scattered melanin pigment (arrow), and ballooned neurons. (Hematoxylin-eoszn, x 600.) The insert illustrates a pigmented neuron with neurofibrilla~degeneration. (Hematoxylin-eosin, X 1,500.)
haloperidol. Incubation was terminated by rinsing sections twice for 5 minutes in cold Tris-HCI buffer [7, 83. After washing, for both receptors, sections were quickly dried in a cold-air stream. Autoradiograms were generated by apposing the slide-mounted tissue sections to tritiumsensitive films (3H-Ultrofilm, Leica, Nussloch, Germany) at 4°C for 7 weeks in the case of D 1 receptors and for 10 weeks in the case of D2 receptors. The autoradiograms were analyzed and quantified by using a computer-assisted microdensitometer (Microm IP, Microm Espaiia, Barcelona, Spain). Appropriate standards (Amersham [Buckinghamshire, UKf tritiated microscales), exposed together with the tissues, allowed the transformation of densitometric readings into receptor densities (fmollmg of protein) [9].
l), periaqueductal gray matter, and locus ceruleus. In these brain regions as well as in others, mainly the substantia innominata, dentate nucleus of the cerebellum, and red nucleus, we observed relevant but variably intense gliosis and neuronal loss, with central chromatolysis or granulovacuolar degeneration in the remaining neurons. Slight to moderate gliosis with neither definitive neuronal loss nor neurofibrillary degeneration was observed in the caudate-putamen. Neurochemical Studies These results appear in the Table and are illustrated in Figures 2 and 3. The density of dopamine D1 receptors Density (fmollmg ofprotein) of Dopamine Dl and 0 2 Receptors i n the Progressive Supranuclear Pa& (PSP) Brain as Compared to Control Brains
D1
Results Neuropathological Studies
Macroscopic examination showed generalized brain atrophy most prominent in the midbrain, with an enlarged sylvian aqueduct and third ventricle. Microscopic findings were diagnostic for PSP [lo]. In short, prominent neurofibrillary tangles were seen in the globus pallidus, subthalamic nucleus, substantia nigra (Fig
704 Annals of Neurology
D2
Brain Area
Control
PSP
Control
PSP
Caudate Putamen Substantianigra Frontal cortex
317 +275 +151 +109
325 339 73 122
324 f 58 429 f 69
< 30" < 20"
78
69 40
* 14
~
"Measurementsobtained at three different striatal levels in two separate experiments.
Vol 32 No 5 November 1992
D
C Fig 2. Autoradiographs of D l dopamine receptors as labeled with 3HSCH 23390 in posterior striatum and midbrain sections from control subjects (A, C ) and the patient with pmgressive supranuclear palsy (PSP) {B, D). Note that in PSP striatum (B), Dl receptor densities do not dqfw from control levels (A) in the putamen (P). In adition, D l receptor densities are marked4 reduced in the substantia nigra (SN) of this PSP patient (0)as compared to a control {C).Bar = 2 mm.
in the caudate-putamen and the frontal cortex of the patient was within normal limits as compared to the control group. By contrast, D1 receptors were clearly reduced in the substantia nigra of the patient with PSP in comparison to the control subjects. The density of dopamine D2 receptors was almost negligible in the PSP striatum as compared to control levels. In the human brain, D2 receptors are concentrated over the striatum [7}, but their very low density (< 30-40 fmol/mg of protein) normally in the substantia nigra and neocortex does not allow comparison between the patient and control subjects.
Brief Communication: Pascual et al: D1 and D2 Dopamine Receptors in PSP
705
B
A Pig 3. Autoradiographs of dopamine 0 2 receptors as labeled with 3H-spiperone in anterior striatum sections from control (A) and patient (B) brains. Note that in the patient, 0 2 receptor densities in the caudute (C)-putamen(P) are negiglible, as compared to the control. Bar = 2 mm.
Discussion This is the first report studying dopamine D1 and D2 receptors in PSP by using quantitative autoradiography, thus allowing analysis of the density of these receptors in discrete brain areas. Our study confirms and extends previous findings of a reduction in dopamine D2 receptors in the caudate-putamen of PSP patients 14, 51. In fact, the PSP patient studied here exhibited an almost complete loss of these receptors in both the caudate and the putamen. Dopamine D2 receptors are thought to be located both on dopaminergic nigrostriatal terminals and, perhaps preferably, on large and medium spiny striatal neurons, thus being preserved in pure presynaptic parkinsonian syndromes (8, 11, 121. In our patient, and as is typical in PSP, nigral and striatal degeneration was neuropathologically confirmed, thus correlating with the neurochemical data. Furthermore, D2 downregulation secondary to dopaminergic treatments might partly explain the loss of D2 receptors. Intriguingly, D1 receptors are preserved in the PSP strianun. In the human species, the preservation of D1 receptors in PD, despite the marked nigrostriatal degeneration taking place in this degenerative disorder, strongly suggests a postsynaptic localization of dopamine D1 receptors [12-151. The preservation of dopa-
mine D1 receptors in this patient with PSP, in spite of the important nigral degeneration, also weighs against many D1 receptors being present on nigrostriatal terminals. Recently, it was reported that the neuronal degeneration occurring in PSP striatum is not homogeneous but selective for the large striatal neurons [lGl where D2 and muscarinic receptors are believed to be located [5}. Thus, D1 receptors could be located on one of the several kinds of intrinsic striatal neurons that do not degenerate in this condition. Finally, in theory, as was recently proposed for P-adrenoceptors [17}, dopamine D1 receptors could potentially be located on glial cells, which are known to proliferate in PSP striatum as a result of the striatal neuronal loss. However, lesion models in experimental animals do not lend weight to this hypothesis 1181. Although the loss of nigral D1 receptors in this PSP patient could be explained by the observed neuronal nigral degeneration, the preservation of nigral D1 receptors in patients with PD 112-151 may indicate that the loss of D1 nigral receptors in PSP could be secondary to the degeneration of nigral terminals of gammaaminobutyric acid (GABA)ergic or substance P-containing neurons projecting from the striatum (181. Therefore, our receptor studies in a typical patient with PSP show again that the loss of D2 receptors is the most plausible explanation for the absence of response to dopaminergic drugs. However, the preservation of “postsynaptic” dopamine D 1 receptors indicates that the clinical effects of agonist drugs acting selectively on D1 receptors are worth testing in PSP.
706 Annals of Neurology Vol 32 No 5 November 1992
a hi^ work was supported by grant 852184 from Comisibn Asesora de Investigacion Cientifica y Tecnica (A. P. and J. B.). We are indebted to the neurologists Drs Felix Fernhdez and M. Jose reviewedwho Sedano, the also manuscript. managed this patient. Mr John Hawkins stylistically
1. Steele JC, Richardson JC, Olzewski J. Progressive supranuclear References palsy. Arch Neurol 1964;10:333-359 2. Perkin GD, Lees AJ, Stern GM, Kocen RS. Problems in the diagnosis of progressive supranuclear palsy. J Can Sci Neurol 1978;5:167-173 3. Klawans HL, Ringel SP. Observations on the efficacy of L-dopa in progressive supranuclear palsy. Eur Neurol 1971;5:115-129 4. Bokobza B, Ruberg M, Scatton B, et al. 3H-Spiperone binding, dopamine and HVA concentrations in Parkinson's disease and supranuclear palsy. Eur J Pharmacol 1984;99:167-175 5. Ruberg M, Javoy-Agid F, Hirsch E, et al. Dopaminergic and cholinergic lesions in progressive supranuclear palsy. Ann Neurol 1985;18:523-529 6. Cortks R, Gueye B, Pazos A, et al. Dopamine receptors in human brain: autoradiographic distribution of D, sites. Neuroscience 1989;28:263-273 7. Camps M, Cortes R, Gueye B, et al. Dopamine receptors in human brain: autoradiographic distribution of D, sites. Neuroscience 1989;28:275-290 8. PascualJ, Pazos A, del Olmo E, et al. Presynaptic parkinsonism in olivopontocerebellar atrophy: clinical,pathological and neurochemical evidence. Ann Neurol 1991;30:425-428 9. Unnerstall JR, Niehoff DL, Kuhar MJ, Palacios JM. Quantitative receptor autoradiography using [3H]-Ultrofilm: application of multiple benzodiazepine receptors. J Neurosci Methods 1982;6:59-73 10. Steele JC. Progressive supranuclear palsy. In: Vinken PJ, Bruyn GW, eds. Handbook of clinical neurology, vol22. System disorders and atrophies. Amsterdam: North-Holland, 1975:217-230 11. Guttmann M, Seeman P, Reynolds GP, et al. Dopamine D, receptor density remains constant in treated Parkinson's disease. Ann Neurol 1986;19:487-492 12. Cortes R, Camps M, Gueye B, et al. Dopamine receptors in human brain: autoradiographic distribution of D, and D, sites in Parkinson syndrome of different etiology. Brain Res 1989; 483130-38 13. Pimoule C, Schoemacker H, Reynolds GP, Lager SZ. 3H-SCH 23390 labeled D, receptors are unchanged in schizophrenia and Parkinson's disease. Eur J Pharmacol 1985;114:235-237 14. Raisman R, Cash R, Ruberg M, et al. Binding of 3H-SCH23390 to D, receptors in the putamen of control and parkinsonian subjects. Eur J Pharmacol 1985;113:467-468 15. Rinne JO, Rinne JK, Laakso K, et al. Dopamine D, receptors in the parkinsonian brain. Brain Res 1985;359:306-310 16. Oyanagi K, Takahashi H, Wakabayashi K, Ikuta F. Selective decrease of large neurons in the neostrianun in progressive supranuclear palsy. Brain Res 1988;458:218-223 17. Waeber C, Rig0 M, Chinaglia C, et al. Beta-adrenergic subtypes in the basal g@a of patients with Huntington's chorea and Parkinson's disease. Synapse 1991;8:270-280 18. Creese I, Sibley DR, Hamblin MW, I& SE. The classification of dopamine receptors: relationship to radiohgand binding. Annu Rev Neurosci 1983;6:43-71
SeVeritv Of X-Linked Recessive Bulbospinal Neuronopathy Correlates with Size of the Tandem CAG Repeat in Androgen Keceptor Gene Manabu Doyu, MD,*'F Gen Sobue, MD,* Eiichiro Mukai, MD,S Teruhiko Kachi, MD,§ Takeshi Yasuda, MD," Terunori Mitsuma, MD,* and Akira Takahashi, MD'F The genetic mutation of X-linked recessive bulbospinal neuronopathy is amplification of a polymorphic tandem CAG repeat in the androgen receptor gene. We studied this CAG repeat in 26 Japanese patients from 2 1families with X-linked recessive bulbospinal neuronopathy. The number of CAG repeats was significantly correlated with the age at onset of limb muscular weakness (r = -0.596, p < 0.001) and age-adjusted scored disability (r = 0 . 4 4 6 , ~< 0.03). The length of the CAG repeat therefore seem to be a determinant factor of clinical severity. Doyu M, Sobue G, Mukai E, Kachi T, Yasuda T, Mitsuma T, Takahashi A. Severity of X-linked recessive bulbospinal neuronopathy correlates with size of the tandem CAG repeat in androgen receptor gene. Ann Neurol 1992;32:707-710 X-linked recessive bulbospinal neuronopathy (XBSNP) is an adult form of hereditary motor neuronopathy: The age at onset and severity of muscular weakness and wasting vary among patients El-41, as do the associated endocrine features 12, 3, 51. Androgen receptor (AR) gene mutations show an increased number of a polymorphic tandem CAG repeats in the coding region, which is a specific abnormality in the X-BSNP gene C61. The number of CAG repeats is highly variable in different patients 161. We have analyzed the number of CAG repeats in 26 Japanese patients with X-BSNP, and related this to the severity of muscle wasting and age at onset. From the *Division of Neurology, Fourth Department of Internal Medicine, Aichi Medical University, Nagakute, Aichi; tDepartment of Neurology, Nagoya University School of Medicine, Nagoya; SDepartment of Neurology, National Nagoya Hospital, Nagoya; 5De artment of Neurology, National Chubu Hospital, Obu; and Department of Neurology, Nagoya Daini Red Cross Hospital,
K
Nagoya, Japan. Received Mar 30, 1992, and in revised form May 20. Accepted for publication May 22, 1992. Address correspondence to Dr Sobue, Division of Neurology, Fourth Department of Internal Medicine, Aichi Medical University, Nagakute, Aichi 480-11, Japan.
Copyright 0 1992 by the American Neurological Association 707
