Epilepsia, 16:765-769,1975. Raven Press, New York
Levels of Free Amino Acids in Serum and Cerebrospinal Fluid After Administration of Taurine to Epileptic and Normal Subjects R. Mutani,* F. Monaco,* L. Durelli, and M. Delsedime Clinic of Nervous and Mental Diseases, Turin University Medical School, 10126 Turin, Italy
(Received in final form October 19,1975) INTRODUCTION Biochemical investigations both in animals and in man have shown that the content of free amino acids, especially of taurine, is diminished in epileptic brain (Koyama, 1972; Van Gelder, 1972; Van Gelder et al., 1972; Craig and Hartman, 1973). Since free amino acids are in dynamic equilibrium in brain, blood, and cerebrospinal fluid (CSF) (Lajtha, 1968; Levi, 1968),changes in the content of amino acids in serum and CSF were studied. In patients with epilepsy glutamic acid in CSF was diminished (Mutani et al., 1974c) and most amino acids were low in serum with the exception of taurine, which was increased (Monaco et al., 1975). It has been suggested that taurine may act as inhibitory neurotransmitter (Davison and Kaczmarek, 1971) or to stabilize membrane excitability (Barbeau and Donaldson, 1974). When taurine was given to epileptic animals the level of amino acids in brain returned to normal (Van Gelder, 1972) and seizures diminished (Van Gelder, 1972; Izumi et al., 1973, 1974, 1975; Kaczmarek and Adey, 1974; Mutani et al., 1974a.b). Taurine also has antiepileptic properties in patients (Barbeau and Donaldson, 1974; Bergamini' et al., 1974), and a recent report by Van Gelder et al. (1975)indicates Key words: Taurine administration in epilepsy - Amino acid normalization in serum - Glutamate increase in CSF *Present address: Clinic of Nervous and Mental Diseases, Sassari University Medical School, 07100 Sassari, Italy.
that, after treatment with taurine, the brain of patients with epilepsy does not show the abnormalities in amino acid content observed without taurine (Van Gelder et al., 1972). To obtain evidence on the role of taurine in patients with epilepsy we determined the content of free amino acids in serum and CSF during treatment with taurine. MATERIALS AND METHODS Six patients, 4 men and 2 women 15 to 30 years old, were selected from the group of patients in whom the content of free amino acids had been determined in serum (Monaco et al., 1975) and in CSF (Mutani et al., 1974~). All had severe epilepsy: 2 had primarily and 2 secondarily generalized epilepsy; 2 had complex partial seizures. The patients were maintained during treatment with taurine on the same anticonvulsant therapy as during the previous studies. Following the technique of Bergamini et al. (1974),the patients were given a slow (1hr) i.v. perfusion of taurine (150 mg/kg, O-DueR, Falorni, Florence, Italy) every 12 hr (at 8 A.M. and 8 P.M.) for 6 days. At the end of the first and last administration of taurine, 5 ml CSF and 10 ml blood were drawn after an overnight fast. The blood was immediately centrifuged (at 3,500 rpm for 10 min) and both serum and CSF were deproteinized by 5 ml of 3.75% sulfosalicylic acid/ml. The free amino acid content was then determined by ion-exchange chromatography, employing an automatic apparatus (Aminolyzer, Optica Co., Milan,
765
766
R. MUTANI ET AL.
Italy), according to routine procedure (Mondino, 1967; Mondino et al., 1972). The EEG was recorded daily during treatment with taurine. Because of slow metabolism and accumulation of taurine by the heart (Awapara, 1957; Gaitonde, 1970), EKGs as well as tests of liver function were performed before, during, and after treatment. No abnormality was found. The same procedures, treatment with taurine and biochemical determinations, were performed,' in 6 healthy subjects of both sexes, 21 to 24 years old (5 medical students and a doctor). The normal subjects were selected from the controls in whom the content of free amino acids in serum was determined (Monaco et al., 1975). The normal values in CSF have been reported (Mutani et al., 1 9 7 4 ~ ) . All patients (or their relatives) and control subjects were informed of the aim of the investigation and consented to the procedures. RESULTS Electroclinical Effects of Treatment with Taurine In 5 patients paroxysmal EEG discharges decreased markedly after 3 to 5 days of taurine administration, in agreement with Bergamini et al. (1974). In the 6th patient (secondarily generalized epilepsy) seizures disappeared.
of those amino acids which were normal prior to administration of taurine. The findings were similar at the end of the 6-day therapy (Time 2) (Table 1,sixth column). In control subjects. The level of taurine increased even more, about 15-fold, at the end of both the first and the last infusion of taurine. There was no significant change in any other amino acid (Table 1, third and fifth columns).
CSF In patients with epilepsy. Before treatment with taurine only the content of glutamic acid was significantly altered: only a trace was found (Mutani et al., 1974c) (Table 2, fourth column). The only change after taurine i.v. was in taurine itself, which increased fourfold (Table 2, second column). After the last infusion, the increase in taurine was much larger, about 4 8 times the basal value, and the content of glutamic acid was above normal levels, rising to 110 pmoles/liter (Table 2, sixth column). In control subjects. The increased level of taurine was less after the first infusion than in patients and the level of glutamic acid was not changed (Table 2, third and fifth columns). DISCUSSION
The amino acid levels in serum that were low prior to therapy (Monaco et al., 1975) inBiochemical Determinations creased toward the norm in patients with epilepsy after the i.v. administration of taurine. Serum In fact, transport of amino acids toward the In patients with epilepsy. Before treatment brain is the result of competitive interaction at with taurine the level of most amino acids was the stereo-selective uptake sites of the bloodlower than in normal subjects, only taurine brain barrier (Guroff and Udenfriend, 1962; being increased (Monaco et al., 1975) (Table 1, Blasberg and Lajtha, 1966; Battistin et al., second column). At the end of the first i.v. 1971), and therefore the large increase of taurine infusion (Time l ) , the content of taurine content after both the first and last i.v. taurine increased about sevenfold, while the infusion makes unnecessary the decrease in the concentrations of the other amino acids rose other competitive amino acids. Experimental studies have shown that adtoward normal (Table 1, fourth column). No ministration of taurine does not increase its significant changes were observed in the levels uptake by the brain in normal animals (Kandera et al., 1968; Levi, 1968). Therefore, if the uptake of amino acids by human brain is like 'With the exception that CSF was not that of animals, no increase in serum amino examined before treatment with taurine. acids would be necessary to counteract the
767
TAURINE IN EPILEPSY TABLE 1 Amino acids Taurine Cystine Threonine Serine Asparagine Glutamine Proline Alanine Citrulline Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Tryptophan Ornithine Aspartic acid Glutamic acid Arginine Glvcine GABA
Before taurine Controls Epileptics
69 f 32 49 f 11 122 f 17 108 f 12 43f 6 631 f 57 231 f 45 370 f 41 41k 6 250 f 27 21f 3 65f 9 137 17 6lf 6 57f 7 54f 6 75 f 13 6f 3 37 f 12 69f 8 220 f 38 n.d.
*
Time 1 Controls Epileptics
Time 2 Controls Epileptics
190+31* 1115f 91* 1305 f 222* 1151 f 136* 1404 f 165* 44f 9 26f 4* 44f 5 41f 9 54f 12 65f15* 110f 44 109f 26 9 2 f 32 99f 25 9 9 f 29 6 9 f 9* 107f 22 9 6 f 22 1OOf 12 35f 5 17f10* 40f 9 tr. 37f 2 563f 54 665 f 121 475 75* 590 f 104 702 f 137 243f 64 240f 31 163 k 28* 285 f 123 233f 67 338f 67 367f 27 248 + 31* 378 f 113 342f 24 24k 2* 37f 4 37f 8 36f 5 39f 5 229f 17 208k 41 181f27* 210f 37 257 f 26 18f 10 1Of 1* 19f 6 18f 7 18f 5 6 8 f 10 55f 11 67k 11 39f 5* 52f 15 127f 12 109f 19 87k 8* 102f 27 136f 17 57f 8 3 3 + 6* 57f 6 60f 1 49f 5 48f 5 49f 12 3 2 2 4* 51f 10 42f 6 4 9 k 11 30k 1* 49f 5 49k 6 46f 4 79f 20 3 9 2 4* 6 8 f 15 6 6 f 16 66f 16 6f 1 5f 2 5f 3 6f 1 6f 2 4 1 k 27 33+-12 35k 10 30f 11 33k 18 67f 20 612 7 75f 19 8 2 f 34 79f 21 200f31 198f 85 222f 84 201f 32 193f 38 n-d. n.d. n.d. n.d. ~~. ~~. .~~ n.d.
*
~~~
Modifications of free amino acid levels in serum induced by taurine administration in 6 epileptics and 6 normal subjects Time 1: after first taurine perfusion; Time 2: after 12th taurine perfusion. The values (rounded off to full numbers) are expressed in pmoles/liter (mean and SD). * = P < 0.01 by Student’s t-test referring to the values of first column: tr. = trace: n.d. = nondetectable.
increased taurine caused by infusion of taurine, and we found no increase in normal human subjects. The main action of taurine on the content of amino acids in CSF was an increase in glutamic acid after 1 2 i.v. infusions of taurine given twice daily, i.e., after the improvement of the electroclinical signs of epilepsy. In fact, the biochemical recovery of the brain is a prerequisite for improvement of epilepsy (Van Gelder, 1972). Glutamic acid is greatly diminished in the CSF of patients with epilepsy (Mutani et al., 1 9 7 4 ~ ) Similarly, . experimental data indicate that administration of taurine reverses the glutamate deficit in epileptic brain (Van Gelder, 1972), and recent findings in patients with epilepsy (Van Gelder et al., 1975) show that therapy with taurine corrects the deficit. Since taurine-induced increase of glutamic acid in the CSF resulted in above-normal levels, the dose of taurine may have been larger than necessary, as suggested by Barbeau and Donald-
son (1974), and determination of the content of glutamate in CSF could help to find the correct therapeutic dose.
SUMMARY The modifications associated with taurine treatment of the free amino acid content of serum and cerebrospinal fluid were investigated in epileptic and control subjects. In patients with epilepsy the main findings were, in the serum, the correction toward normal of the amino acid levels that were low prior to therapy, and in the cerebrospinal fluid, the increase up to above-normal levels of glutamic acid, greatly diminished before treatment. Thus taurine, which has an anticonvulsant action, appears to partially correct the amino acid imbalance in epileptics. The monitoring of taurine-induced glutamate changes in the cerebrospinal fluid could help to establish the correct therapeutic dose.
R. MUTANI ET AL.
768
TABLE 2.
Amino acids Taurine Cystine Threonine Serine Asparagine Glutamine Proline Alanine Citrulline Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Tryptophan Ornithine Aspartic acid Glutamic acid Arginine Glycine GABA
Before taurine Controls Epileptics
Time 1 Controls Epileptics
5f 1
5f 1
l l f 1*
20f 3*
n.d.
n.d.
n.d.
n.d.
25f 4 25f 3 27f 4 252 6 4f 1 4f 1 514 f 33 497 f 27 tr.
25f 1f 13f 2f 4f 12+ 6+ 5f 6f 6f 2f 45+ 24f 42 n.d.
n.d.
6 0.2 4 0.3 1 2 1 2 2 1 0.3 8 4 1
tr.
25f 4 tr.
15f 2f 5f 13f 7f 5f 72 6f 2+
26f 4 292 4 6f 2 499 + 83 27f 6 tr.
2 0.2 1 2 1 1 2 1 0.2
27f 6 24f 7 5f 1 547 f 88 n.d.
27+ 8
22f 4 4f 1
18f 7 6f 1
n.d.
n.d.
n.d.
tr.*
8f 6+ 6f
5f 3f
267 f 94* 241 f 82* n.d.
7 0.4 3 6 1 2 2 2 1
tr.*
n.d.
30f 15 29f 4 31f 13 30 f 11 85 4 4f 1 496 f103 580 f 90 tr.
33+ 10 tr.
tr.
13f 4 3f 1 5f 2 12+ 3 6f 1 7f 2 5f 3 6f 1 3f 1 55 f 12 20 f 11 6f 2
16f 2f 7f 15f
Time 2 Controls Epileptics
n.d.
26f 2 tr.
17f 3f
7 15f 4 3f 1 1 62 2 6f 2 12f 3 17f 6 7f 2 8+ 2 8f 3 5+ 3 5f 1 5f 2 65 2 7f 3 3f 1 2 + 0.1 57 f 26 110 f 47* 19f 7 22 f 12 9f 4 8f 4 n.d.
n.d.
Modifications of free amino acid levels in CSF induced by taurine administration in 6 epileptics and 6 normal subjects. Control values before taurine taken from Mutani et al. ( 1 9 7 4 ~ ) . Time 1: after first taurine perfusion; Time 2: after 12th taurine perfusion. The values (rounded off to full numbers) are expressed in pmoles/liter (mean and SD). * = p < 0.01 by Student’s t-test referring to the values of first column; tr. = trace; n.d. = nondetectable.
RESUME Chez des sujets Bpileptiques et des sujets de contrale normaux, on a BtudiB les modifications des aminoacides libres dans le serum et le LCR en relation avec l’administration de taurine. Chez les sujets Bpileptiques, les donnees les plus significatives etaient les suivantes: (1) dans le &rum, les taux des aminoacids qui Btaient bas, avant le traitement, augmentaient jusqu’i approcher des taux normaux, (2) dans le LCR, les taux de l’acide glutamique qui Btait tr6s diminuB avant le traitement augmentait jusqu’8 des niveaux superieurs B la normale. I1 semble donc que la taurine, produit ayant une action antiBpileptique, corrige partiellement le trouble des aminoacidels chez les Bpileptiques. Le dosage des modifications de l’acide glutamique dans le LCR induites par la taurine pourrait aider B mieux prBciser les doses thkrapeutiques ad6quates. (C. A. Tassinari, Marseilles)
aminoicidos libres que se derivan del tratamiento con taurina administrado a enfermos epilepticos y en sujetos control. En 10s epilBpticos se observ6, en el suero, una normalizaci6n de 10s niveles de aminoicidos que estaban reducidos antes del tratamiento. En el liquido cBfalo-raquideo se registr6 un aumento del ficido glutimico, muy reducido antes del tratamiento, hasta niveles superiores a lo normal. Asi puBs la taurina, que posee una acci6n anticonvulsivante, parece ser capaz de corregir parcialmente el desequilibrio de aminoicidos de 10s epilBpticos. La monitorizaci6n en el liquido cBfalo-raquideo de 10s cambios de 10s glutamatos inducidos por la taurina podria servir para establecer las dosis terapecticas correctas. (A. Portera, Madrid)
ZUSAMMENFASSUNG
Bei epileptischen Patienten und Kontrollen wurden die Veranderungen der freien Aminosiiuren im Serum und in der CerebrospinalRESUMEN fliissigkeit nach Gabe von Taurin untersucht. Die wesentlichen Befunde bei Patienten mit Se han investigado en el suer0 y en el liquido Epilepsie bestanden darin, dass im Serum die cBfalo-raquideo las modificaciones d e 10s Spiegel der Aminosiiuren, die vor der Therapie
TAURINE IN EPILEPSY niedrig waren, normalisiert wurden. Im Liquor cerebrospinales wurden der Spiegel von Glutaminsiiure, der vor Behandlung stark vermindert war, auf ubernormale Werte erhoht. Damit scheint es, dass Taurin, das antikonvulsive Wirking besitzt, teilweise die Aminosiiurenimbalance bei Anfallskranken zu korrigieren scheint. Die Verfolgung der durch Taurin induzierten Glutamatveranderungen in der Cerebrospinalflussigkeit konnte beitragen eine korrekte therapeutische Dosis zu finden.
769
taurine and GABA. Brain Res 88:576-579, 1975. Kaczmarek LK and Adey WR. Factors affecting the release of 14C taurine from cat brain: The electrical effects of taurine o n normal and seizure prone cortex. Brain Res 76:83-94.1974. Kandera J, Levi G, and Lajtha A. Control of cerebral metabolite levels. 11. Amino acid uptake and levels in various areas of the rat brain. Arch Biochem Biophys 126:249-260, 1968. (D. Scheffner, Heidelberg) Koyama I. Amino acid content in the cobalt-induced epileptogenic and nonepileptogenic ACKNOWLEDGMENTS cat’s cortex. Can J Physiol Pharmacol 50:740-752,1972. We gratefully acknowledge the technical help provided by the R.B.M. Biomedical Insti- Lajtha A. Transport as control mechanism of cerebral metabolite levels. In: A Lajtha and tute, Ivrea, Italy, and in particular we want to DH Ford (Eds), Progress in Brain Research, thank Dr. A. Mondino and Dr. S. Fumero. Vol 29, Brain Barrier Systems Elsevier, Amsterdam, 1968,pp 201-218. This work was supported by a grant from Levi G. Regional differences in cerebral amino Falorni, Florence, Italy. acid transport. In: A Lajtha and DH Ford REFERENCES (Eds), Progress in Brain Research, Vol. 29, Brain Barrier Systems. Elsevier, Amsterdam, Awapara J. Absorption of injected tau15ne-S~’ 1968,pp 219-228. by rat organs. J Biol Chem 225:857-882, Monaco F, Mutani R, Durelli L, and Delsedime 1957. M. Free amino acids in serum of patients Barbeau A and Donaldson J. Zinc, taurine and with epilepsy: Significant increase in taurine. epilepsy. Arch Neurol30:52-58,1974. Epilepsia 16:245-249,1975. Battistin L, Grynbaum A, and Lajtha A. The uptake of various amino acids by the mouse Mondino A. A new system of automatic amino acid analysis. J Chromatogr 3O:lOO-112, brain in vivo. Brain Res 29:85-99,1971. 1967. Bergamini L, Mutani R, Delsedime M, and Durelli L. First clinical experience on the Mondino A, Bongiovanni G, Fumero S, and Rossi L. An improved method of plasma antiepileptic action of taurine. Eur Neurol deproteination with sulphosalicylic acid for 11:261-269,1974. determining amino acids and related comBlasberg R and Lajtha A. Heterogeneity of the pounds. J Chromatogr 74:255-263,1972. mediated transport systems of amino acid uptake in brain. Brain Res 1:86-104,1966. Mutani R, Bergamini L, Delsedime M, and Durelli L. Effects of taurine on chronic Craig CR and Hartman ER. Concentration of experimental epilepsy. Brain Res amino acids in the brain of cobalt-epileptic 79~330-332, 1974b. rat. Epilepsia 14:409-414,1973. Davison AN and Kaczmarek LK. Taurine - a Mutani R. Bergamini L, Fariello R, and n e u r o t r a n s m i t t er? Nature Delsedime M. Effects of taurine on cortical p o ss i b 1e acute epileptic foci. Brain Res 70:170-173, 234:107-108,1971. 1974a. Gaitonde MK. Sulfur amino acids. In: A Lajtha (Ed), Handbook of Neurochemistry, VoL II. Mutani R, Monaco F, Durelli L, and Delsedime Plenum Press, New York, 1970,pp 253-287. M. The free amino acids in the CSF of epileptic subjects. Epilepsia 15:593-597,1974c. Guroff S and Udenfriend S. Studies on aromatic amino acid uptake by rat brain in vivo. Van Gelder NM. Antagonism by taurine of JBiol Chem 237:803-806,1962. cobalt induced epilepsy in cat and mouse. Izumi K, Donaldson J, Minnich J, and Barbeau Brain Res 47:157-165,1972. A. Ouabain-induced seizures in rats: Sup- Van Gelder NM, Sherwin AM, and Rasmussen pressive effects of taurine and GABA. Can J T. Amino acid content of epileptogenic Physiol Pharmacol 51 :885-889,1973. human brain: Focal versus surrounding Izumi K, Igisu H, and Fukuda T. Suppression of regions. Brain Res 40:385-393,1972. seizures by taurine - specific or nonspecific? Van Gelder NM, Sherwin AM, Sacsk C, and Bmin Res 76:171-173,1974. Anderman F. Biochemical observations following administration of taurine to patients Izumi K, Igisu H, and Fukuda T. Effects of edetate on seizures, suppressive action of with epilepsy. Brain Res 94:297-306,1975.
Levels of Free Amino Acids in Serum and Cerebrospinal Fluid After Administration of Taurine to Epileptic and Normal Subjects R. Mutani,* F. Monaco,* L. Durelli, and M. Delsedime Clinic of Nervous and Mental Diseases, Turin University Medical School, 10126 Turin, Italy
(Received in final form October 19,1975) INTRODUCTION Biochemical investigations both in animals and in man have shown that the content of free amino acids, especially of taurine, is diminished in epileptic brain (Koyama, 1972; Van Gelder, 1972; Van Gelder et al., 1972; Craig and Hartman, 1973). Since free amino acids are in dynamic equilibrium in brain, blood, and cerebrospinal fluid (CSF) (Lajtha, 1968; Levi, 1968),changes in the content of amino acids in serum and CSF were studied. In patients with epilepsy glutamic acid in CSF was diminished (Mutani et al., 1974c) and most amino acids were low in serum with the exception of taurine, which was increased (Monaco et al., 1975). It has been suggested that taurine may act as inhibitory neurotransmitter (Davison and Kaczmarek, 1971) or to stabilize membrane excitability (Barbeau and Donaldson, 1974). When taurine was given to epileptic animals the level of amino acids in brain returned to normal (Van Gelder, 1972) and seizures diminished (Van Gelder, 1972; Izumi et al., 1973, 1974, 1975; Kaczmarek and Adey, 1974; Mutani et al., 1974a.b). Taurine also has antiepileptic properties in patients (Barbeau and Donaldson, 1974; Bergamini' et al., 1974), and a recent report by Van Gelder et al. (1975)indicates Key words: Taurine administration in epilepsy - Amino acid normalization in serum - Glutamate increase in CSF *Present address: Clinic of Nervous and Mental Diseases, Sassari University Medical School, 07100 Sassari, Italy.
that, after treatment with taurine, the brain of patients with epilepsy does not show the abnormalities in amino acid content observed without taurine (Van Gelder et al., 1972). To obtain evidence on the role of taurine in patients with epilepsy we determined the content of free amino acids in serum and CSF during treatment with taurine. MATERIALS AND METHODS Six patients, 4 men and 2 women 15 to 30 years old, were selected from the group of patients in whom the content of free amino acids had been determined in serum (Monaco et al., 1975) and in CSF (Mutani et al., 1974~). All had severe epilepsy: 2 had primarily and 2 secondarily generalized epilepsy; 2 had complex partial seizures. The patients were maintained during treatment with taurine on the same anticonvulsant therapy as during the previous studies. Following the technique of Bergamini et al. (1974),the patients were given a slow (1hr) i.v. perfusion of taurine (150 mg/kg, O-DueR, Falorni, Florence, Italy) every 12 hr (at 8 A.M. and 8 P.M.) for 6 days. At the end of the first and last administration of taurine, 5 ml CSF and 10 ml blood were drawn after an overnight fast. The blood was immediately centrifuged (at 3,500 rpm for 10 min) and both serum and CSF were deproteinized by 5 ml of 3.75% sulfosalicylic acid/ml. The free amino acid content was then determined by ion-exchange chromatography, employing an automatic apparatus (Aminolyzer, Optica Co., Milan,
765
766
R. MUTANI ET AL.
Italy), according to routine procedure (Mondino, 1967; Mondino et al., 1972). The EEG was recorded daily during treatment with taurine. Because of slow metabolism and accumulation of taurine by the heart (Awapara, 1957; Gaitonde, 1970), EKGs as well as tests of liver function were performed before, during, and after treatment. No abnormality was found. The same procedures, treatment with taurine and biochemical determinations, were performed,' in 6 healthy subjects of both sexes, 21 to 24 years old (5 medical students and a doctor). The normal subjects were selected from the controls in whom the content of free amino acids in serum was determined (Monaco et al., 1975). The normal values in CSF have been reported (Mutani et al., 1 9 7 4 ~ ) . All patients (or their relatives) and control subjects were informed of the aim of the investigation and consented to the procedures. RESULTS Electroclinical Effects of Treatment with Taurine In 5 patients paroxysmal EEG discharges decreased markedly after 3 to 5 days of taurine administration, in agreement with Bergamini et al. (1974). In the 6th patient (secondarily generalized epilepsy) seizures disappeared.
of those amino acids which were normal prior to administration of taurine. The findings were similar at the end of the 6-day therapy (Time 2) (Table 1,sixth column). In control subjects. The level of taurine increased even more, about 15-fold, at the end of both the first and the last infusion of taurine. There was no significant change in any other amino acid (Table 1, third and fifth columns).
CSF In patients with epilepsy. Before treatment with taurine only the content of glutamic acid was significantly altered: only a trace was found (Mutani et al., 1974c) (Table 2, fourth column). The only change after taurine i.v. was in taurine itself, which increased fourfold (Table 2, second column). After the last infusion, the increase in taurine was much larger, about 4 8 times the basal value, and the content of glutamic acid was above normal levels, rising to 110 pmoles/liter (Table 2, sixth column). In control subjects. The increased level of taurine was less after the first infusion than in patients and the level of glutamic acid was not changed (Table 2, third and fifth columns). DISCUSSION
The amino acid levels in serum that were low prior to therapy (Monaco et al., 1975) inBiochemical Determinations creased toward the norm in patients with epilepsy after the i.v. administration of taurine. Serum In fact, transport of amino acids toward the In patients with epilepsy. Before treatment brain is the result of competitive interaction at with taurine the level of most amino acids was the stereo-selective uptake sites of the bloodlower than in normal subjects, only taurine brain barrier (Guroff and Udenfriend, 1962; being increased (Monaco et al., 1975) (Table 1, Blasberg and Lajtha, 1966; Battistin et al., second column). At the end of the first i.v. 1971), and therefore the large increase of taurine infusion (Time l ) , the content of taurine content after both the first and last i.v. taurine increased about sevenfold, while the infusion makes unnecessary the decrease in the concentrations of the other amino acids rose other competitive amino acids. Experimental studies have shown that adtoward normal (Table 1, fourth column). No ministration of taurine does not increase its significant changes were observed in the levels uptake by the brain in normal animals (Kandera et al., 1968; Levi, 1968). Therefore, if the uptake of amino acids by human brain is like 'With the exception that CSF was not that of animals, no increase in serum amino examined before treatment with taurine. acids would be necessary to counteract the
767
TAURINE IN EPILEPSY TABLE 1 Amino acids Taurine Cystine Threonine Serine Asparagine Glutamine Proline Alanine Citrulline Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Tryptophan Ornithine Aspartic acid Glutamic acid Arginine Glvcine GABA
Before taurine Controls Epileptics
69 f 32 49 f 11 122 f 17 108 f 12 43f 6 631 f 57 231 f 45 370 f 41 41k 6 250 f 27 21f 3 65f 9 137 17 6lf 6 57f 7 54f 6 75 f 13 6f 3 37 f 12 69f 8 220 f 38 n.d.
*
Time 1 Controls Epileptics
Time 2 Controls Epileptics
190+31* 1115f 91* 1305 f 222* 1151 f 136* 1404 f 165* 44f 9 26f 4* 44f 5 41f 9 54f 12 65f15* 110f 44 109f 26 9 2 f 32 99f 25 9 9 f 29 6 9 f 9* 107f 22 9 6 f 22 1OOf 12 35f 5 17f10* 40f 9 tr. 37f 2 563f 54 665 f 121 475 75* 590 f 104 702 f 137 243f 64 240f 31 163 k 28* 285 f 123 233f 67 338f 67 367f 27 248 + 31* 378 f 113 342f 24 24k 2* 37f 4 37f 8 36f 5 39f 5 229f 17 208k 41 181f27* 210f 37 257 f 26 18f 10 1Of 1* 19f 6 18f 7 18f 5 6 8 f 10 55f 11 67k 11 39f 5* 52f 15 127f 12 109f 19 87k 8* 102f 27 136f 17 57f 8 3 3 + 6* 57f 6 60f 1 49f 5 48f 5 49f 12 3 2 2 4* 51f 10 42f 6 4 9 k 11 30k 1* 49f 5 49k 6 46f 4 79f 20 3 9 2 4* 6 8 f 15 6 6 f 16 66f 16 6f 1 5f 2 5f 3 6f 1 6f 2 4 1 k 27 33+-12 35k 10 30f 11 33k 18 67f 20 612 7 75f 19 8 2 f 34 79f 21 200f31 198f 85 222f 84 201f 32 193f 38 n-d. n.d. n.d. n.d. ~~. ~~. .~~ n.d.
*
~~~
Modifications of free amino acid levels in serum induced by taurine administration in 6 epileptics and 6 normal subjects Time 1: after first taurine perfusion; Time 2: after 12th taurine perfusion. The values (rounded off to full numbers) are expressed in pmoles/liter (mean and SD). * = P < 0.01 by Student’s t-test referring to the values of first column: tr. = trace: n.d. = nondetectable.
increased taurine caused by infusion of taurine, and we found no increase in normal human subjects. The main action of taurine on the content of amino acids in CSF was an increase in glutamic acid after 1 2 i.v. infusions of taurine given twice daily, i.e., after the improvement of the electroclinical signs of epilepsy. In fact, the biochemical recovery of the brain is a prerequisite for improvement of epilepsy (Van Gelder, 1972). Glutamic acid is greatly diminished in the CSF of patients with epilepsy (Mutani et al., 1 9 7 4 ~ ) Similarly, . experimental data indicate that administration of taurine reverses the glutamate deficit in epileptic brain (Van Gelder, 1972), and recent findings in patients with epilepsy (Van Gelder et al., 1975) show that therapy with taurine corrects the deficit. Since taurine-induced increase of glutamic acid in the CSF resulted in above-normal levels, the dose of taurine may have been larger than necessary, as suggested by Barbeau and Donald-
son (1974), and determination of the content of glutamate in CSF could help to find the correct therapeutic dose.
SUMMARY The modifications associated with taurine treatment of the free amino acid content of serum and cerebrospinal fluid were investigated in epileptic and control subjects. In patients with epilepsy the main findings were, in the serum, the correction toward normal of the amino acid levels that were low prior to therapy, and in the cerebrospinal fluid, the increase up to above-normal levels of glutamic acid, greatly diminished before treatment. Thus taurine, which has an anticonvulsant action, appears to partially correct the amino acid imbalance in epileptics. The monitoring of taurine-induced glutamate changes in the cerebrospinal fluid could help to establish the correct therapeutic dose.
R. MUTANI ET AL.
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TABLE 2.
Amino acids Taurine Cystine Threonine Serine Asparagine Glutamine Proline Alanine Citrulline Valine Methionine Isoleucine Leucine Tyrosine Phenylalanine Tryptophan Ornithine Aspartic acid Glutamic acid Arginine Glycine GABA
Before taurine Controls Epileptics
Time 1 Controls Epileptics
5f 1
5f 1
l l f 1*
20f 3*
n.d.
n.d.
n.d.
n.d.
25f 4 25f 3 27f 4 252 6 4f 1 4f 1 514 f 33 497 f 27 tr.
25f 1f 13f 2f 4f 12+ 6+ 5f 6f 6f 2f 45+ 24f 42 n.d.
n.d.
6 0.2 4 0.3 1 2 1 2 2 1 0.3 8 4 1
tr.
25f 4 tr.
15f 2f 5f 13f 7f 5f 72 6f 2+
26f 4 292 4 6f 2 499 + 83 27f 6 tr.
2 0.2 1 2 1 1 2 1 0.2
27f 6 24f 7 5f 1 547 f 88 n.d.
27+ 8
22f 4 4f 1
18f 7 6f 1
n.d.
n.d.
n.d.
tr.*
8f 6+ 6f
5f 3f
267 f 94* 241 f 82* n.d.
7 0.4 3 6 1 2 2 2 1
tr.*
n.d.
30f 15 29f 4 31f 13 30 f 11 85 4 4f 1 496 f103 580 f 90 tr.
33+ 10 tr.
tr.
13f 4 3f 1 5f 2 12+ 3 6f 1 7f 2 5f 3 6f 1 3f 1 55 f 12 20 f 11 6f 2
16f 2f 7f 15f
Time 2 Controls Epileptics
n.d.
26f 2 tr.
17f 3f
7 15f 4 3f 1 1 62 2 6f 2 12f 3 17f 6 7f 2 8+ 2 8f 3 5+ 3 5f 1 5f 2 65 2 7f 3 3f 1 2 + 0.1 57 f 26 110 f 47* 19f 7 22 f 12 9f 4 8f 4 n.d.
n.d.
Modifications of free amino acid levels in CSF induced by taurine administration in 6 epileptics and 6 normal subjects. Control values before taurine taken from Mutani et al. ( 1 9 7 4 ~ ) . Time 1: after first taurine perfusion; Time 2: after 12th taurine perfusion. The values (rounded off to full numbers) are expressed in pmoles/liter (mean and SD). * = p < 0.01 by Student’s t-test referring to the values of first column; tr. = trace; n.d. = nondetectable.
RESUME Chez des sujets Bpileptiques et des sujets de contrale normaux, on a BtudiB les modifications des aminoacides libres dans le serum et le LCR en relation avec l’administration de taurine. Chez les sujets Bpileptiques, les donnees les plus significatives etaient les suivantes: (1) dans le &rum, les taux des aminoacids qui Btaient bas, avant le traitement, augmentaient jusqu’i approcher des taux normaux, (2) dans le LCR, les taux de l’acide glutamique qui Btait tr6s diminuB avant le traitement augmentait jusqu’8 des niveaux superieurs B la normale. I1 semble donc que la taurine, produit ayant une action antiBpileptique, corrige partiellement le trouble des aminoacidels chez les Bpileptiques. Le dosage des modifications de l’acide glutamique dans le LCR induites par la taurine pourrait aider B mieux prBciser les doses thkrapeutiques ad6quates. (C. A. Tassinari, Marseilles)
aminoicidos libres que se derivan del tratamiento con taurina administrado a enfermos epilepticos y en sujetos control. En 10s epilBpticos se observ6, en el suero, una normalizaci6n de 10s niveles de aminoicidos que estaban reducidos antes del tratamiento. En el liquido cBfalo-raquideo se registr6 un aumento del ficido glutimico, muy reducido antes del tratamiento, hasta niveles superiores a lo normal. Asi puBs la taurina, que posee una acci6n anticonvulsivante, parece ser capaz de corregir parcialmente el desequilibrio de aminoicidos de 10s epilBpticos. La monitorizaci6n en el liquido cBfalo-raquideo de 10s cambios de 10s glutamatos inducidos por la taurina podria servir para establecer las dosis terapecticas correctas. (A. Portera, Madrid)
ZUSAMMENFASSUNG
Bei epileptischen Patienten und Kontrollen wurden die Veranderungen der freien Aminosiiuren im Serum und in der CerebrospinalRESUMEN fliissigkeit nach Gabe von Taurin untersucht. Die wesentlichen Befunde bei Patienten mit Se han investigado en el suer0 y en el liquido Epilepsie bestanden darin, dass im Serum die cBfalo-raquideo las modificaciones d e 10s Spiegel der Aminosiiuren, die vor der Therapie
TAURINE IN EPILEPSY niedrig waren, normalisiert wurden. Im Liquor cerebrospinales wurden der Spiegel von Glutaminsiiure, der vor Behandlung stark vermindert war, auf ubernormale Werte erhoht. Damit scheint es, dass Taurin, das antikonvulsive Wirking besitzt, teilweise die Aminosiiurenimbalance bei Anfallskranken zu korrigieren scheint. Die Verfolgung der durch Taurin induzierten Glutamatveranderungen in der Cerebrospinalflussigkeit konnte beitragen eine korrekte therapeutische Dosis zu finden.
769
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