Bruin Research Bulletin, Vol. 2, pp. 75-77, 1977. Copyright 0 ANKHO All rights of reproduction in any form reserved. Printed in the U.S.A.
International
Inc.
BRIEFCOMMUNICATION Effects of Carbachol and Nicotine Injected into the Cerebral Ventricles on Electromyogram of Conscious Cats’ D. B. BELESLIN’,
S. N. BELLUR
AND M. RADULOVACKI
Departments of Pharmacology and Neurology, University of Illinois at the Medical Center P.O. Box 6998, Chicago, IL 60680 (Received
2 November
1976)
BELESLIN, D. B., S. N. BELLUR AND M. RADULOVACKI. Ejyects of carhachol and nicotine injected into the cerebral ventricles on electromyogram of conscious cats. BRAIN RES. BULL. 2( 1) 15-11, 1917. - Carbachol and nicotine injected into the cerebral ventricles produced high amplitude and fast frequency activity in the electromyogram of conscious cats. Carbachol, much more than nicotine, caused bursts of such activity spaced at irregular time intervals accompanied by marked activity in the electrooculogram. In addition carbachol, but not nicotine, caused adynamia. The effect of nicotine lasted 3-5 hr, while the effect of carbachol lasted up to 6 hr. The obtained results suggest that central muscarinic and nicotinic mediations are involved in the activation of the motor efferent system. Carbachol
Nicotine
Intraventricular
injections
Electromyogram
Electrooculogram
Nicotinic and muscarinic mediations
THERE are a number of reports on movement disorders following systemic and intracerebral administration of nicotine and carbachol. The description of these disorders varies from tremors to convulsions. The best evidence for tremor seems to derive from experiments in which nicotine has been administered systemically and carbachol, intracerebrally [ 3, 5, 61. In addition, adynamia was observed after intracerebral administration of carbachol [ 61, while data concerning the effects of nicotine are still missing. Therefore, in the light of these findings, it was of interest to investigate and to compare the effects of carbachol and nicotine on electromyogram after their injections into cerebral ventricles of conscious cats.
ate electrodes to record electromyogram (EMG) of the neck muscle, electrooculogram (EOG) and electroencephalogram (EEG) were also implanted. Postoperatively, penicillin was administered intramuscularly. The animals were kept in an isolated room in individual cages with continuous light and constant temperature. An interval of 7 days elapsed before cats were used for the experiments. Carbachol chloride and nicotine hydrogen tartarate were dissolved in sterile 0.9% sodium chloride. The solutions, warmed to 37°C were injected slowly under aseptic conditions in volumes of 0.1 ml and washed in with 0.1 ml of 0.9% saline. Drug doses refer to the salts. EEG, EOG and EMG were thereafter monitored continuously for 6 hours and segments of the recordings without gross movement artifacts with the animals apparently restful were considered for analysis.
METHOD
Eight adult male and female cats were used in these experiments. For injection of substance into the cerebral ventricles a Collison cannula was implanted aseptically into the left lateral ventricle [ 61 during pentobarbitone sodium anesthesia (35-45 mg/kg, intraperitoneally). The cannula, with a side hole 1 mm from its closed tip, was directed with the opening towards the foramen of Monro. Dye studies indicated that the injected material passed from the lateral ventricle into the third and the fourth ventricles. Appropri-
RESULTS
Carbachol injected in a dose of 2-5 fig into the lateral ventricle of conscious cats produced intense bursts in the EMG consisting of high amplitude and fast frequency activity after a few minutes, followed by small amplitude activity spaced at irregular time intervals (Fig. 1: 1 B). This type of activity lasted up to 6 hr and was maintained during slow wave sleep as well (Fig. 1: 1 C). With small doses of
‘Reprints available from M. RadulovaEki, Department of Pharmacology, University of Illinois at the Medical Center, P.O. Box 6998, Chicago, Illinois, 60680. This research was supported by USPHS Grant 10921 to M. RadulovaEki. ‘D. B. Beleslin is a Visiting Associate Professor from the Department of Pharmacology, Medical Faculty, Beograd, Yugoslavia. 75
BELESLIN.BELLUR AND RADULOVACKI
R.tiippw
Cxx
L-RFr
EMG’=‘dW
8.
EOGc
R. Hippe L-RFrCxx EMG
R. Hipp L-R
Fr Cx EMG
-
# -
I set
FIG. 1. Electroencephalogram (EEG), electromyogram (EMG) and electrooculogram (EOG) of two conscious cats after administration of carbachol(2 pg) and nicotine (2 mg) into the left lateral cerebral ventricle. 1 A, control, lB, 30 min and lC, 5 hr following carbachol, respectively. 2A, control, 2B, 30 min and ZC, 5 hr following nicotine, respectively. R. Hipp. - right hippocampus. L-R Fr Cx ~ left and right frontal cortex. EMG - electromyogram of the neck muscle.
carbachol (0.04-0.1 /IS), this effect was inconsistent. By increasing the doses of carbachol up tg 10 Mg the depression in the EMG was intensified and in some cats adynamia developed. In the dosage range of 0.04-2 peg the animals did not display much by way of autonomic or behavioral changes. In S- 10 fig dose range they displayed intermittent tremulousness, an exaggerated startle response, minimal piloerection, increased bronchial secretions with coughing, and occasional circling behavior. Intermittent periods of adynamia (EMG suppression), lasting from a few seconds to a few minutes, always occurred after enhanced motor activity. With the above described EMG changes these were no overt behavioral or autonomic correlates. Bursts of increased motor activity during wakefulness were also detected in the EOG (Fig. 1: lB1, the intensity depended on the dose of carbachol. Nicotine injected in a dose of 0.04-02 mg into the lateral ventricle of conscious cats produced high amplitude and fast frequency activity in the EMG after a few minutes (Fig. 1 :2Bl. At the same time, bursts of such activity spaced at irregular time intervals were rarely recorded. However, in 4 out of 16 experiments, depression of the amplitude in the EMG developed after a shortlasting increase. This type of activity lasted 3-5 hr and was obtained when nicotine was used in doses from 0.04-2 mg. Adynamia was not observed even when nicotine in a high dose of 2 mg produced convulsions. The EOG activity, comparison with carbachol, was much less stimulated. Increased EOG activity lasted up to 30-40 min and, in general, cats were quiet (Fig. 1:2BI. When nicotine was injected in doses from 0.5-2 mg, mydriasis, ear twitching,
vomiting, respiratory changes, sometimes akathisia and convulsions accompanied the alterations in the EMG only during the first two hour recording period. DISCUSSION
Gross behavioral changes have already been described as have movement disorders and alterations in the body temperature produced by carbachol and nicotine injected into the cerebral ventricles of cats and monkeys [2,6]. However, the results presented here show that carbachol and nicotine altered the EMG activity of conscious cats when injected into the lateral ventricle. Both agents produced high amplitude and fast frequency activity in the EMG, while carbachol caused more bursts of such activity spaced at irregular time intervals accompanied by marked EOG activity. Further, carbachol, but not nicotine, evoked adynamia. Thus it appears that carbachol and nicotine, acting on the structures lining the cerebral ventricles, activate the efferent motor system causing enhancement in the EMG activity. In this context, it is interesting to note that carbachol injected into the caudate nucleus evokes tremor, while nicotine produced no effect [ 41. Tremor, changes in the body temperature, as well as the gross behavioral phenomena which are caused by carbachol administered into the cerebral ventricles or into the caudate nucleus of cats are blocked by atropine or scopolamine. These effects are resistant to ganglionic and neuromuscular blocking agents [ 2,6]. It appears, therefore, that carhachol activates central muscarinic cholinoceptive sites. On the other hand, there is no conclusive evidence concerning the
CARBACHOL,
NICOTINE
77
AND EMG
central nicotinic mediations [3]. Furthermore, there is evidence that the central effects of nicotine may be mediated, at least in part, by release of acetylcholine [ I] If this is the case, then both nicotinic and muscarinic
mediations [3]. The longlasting
could subserve results obtained effect of nicotine
the central effects of nicotine in this study concerning the on EMG favor this view.
REFERENCES Armitage, A. K., G. H. Hall and C. M. Sellers. Effects of nicotine on electrocortical activity and acetylcholine release from the cat cerebral cortex. Er. J. Pharmac. 35: 152-160, 1969. Beleslin, D. B., L. Grbovid and B. Z. RadmanoviC. The pharmacology of gross behavioural effects of cholinomimetic substances injected into the cerebral ventricles of unanaesthetized cats: evidence for central muscarinic mediation. Neuropharmacology 13: 1163-1169, 1974. Brimblecombe, R. W. Drug Actions on Cholinergic Systems. Baltimore, London, Tokyo: University Park Press: 1974, 191-124 p.
4.
5. 6. 7.
Connor, J. D., G. V. Rossi and W. W. Baker. Analysis of the tremor induced by injection of cholinergic agents into the caudate nucleus. ht. J. Neurooharmac. 5: 207-216. 1966. Feldberg, W. A Pharmacolog& Approach to the brain from its Inner and Outer Surface. London: Edward Arnold (Publishers), 1963. Myers, R. D. Handbook of Drug and Chemical Stimulation of the Brain. New York: Van Nostrand Reinhold Company, 1914. Silvette, H., E. C. Hess, P. S. Larson and H. B. Haag. The actions of nicotine on central nervous Pharmac. Rev. 14: 137-173, 1972.
system
functions.
International
Inc.
BRIEFCOMMUNICATION Effects of Carbachol and Nicotine Injected into the Cerebral Ventricles on Electromyogram of Conscious Cats’ D. B. BELESLIN’,
S. N. BELLUR
AND M. RADULOVACKI
Departments of Pharmacology and Neurology, University of Illinois at the Medical Center P.O. Box 6998, Chicago, IL 60680 (Received
2 November
1976)
BELESLIN, D. B., S. N. BELLUR AND M. RADULOVACKI. Ejyects of carhachol and nicotine injected into the cerebral ventricles on electromyogram of conscious cats. BRAIN RES. BULL. 2( 1) 15-11, 1917. - Carbachol and nicotine injected into the cerebral ventricles produced high amplitude and fast frequency activity in the electromyogram of conscious cats. Carbachol, much more than nicotine, caused bursts of such activity spaced at irregular time intervals accompanied by marked activity in the electrooculogram. In addition carbachol, but not nicotine, caused adynamia. The effect of nicotine lasted 3-5 hr, while the effect of carbachol lasted up to 6 hr. The obtained results suggest that central muscarinic and nicotinic mediations are involved in the activation of the motor efferent system. Carbachol
Nicotine
Intraventricular
injections
Electromyogram
Electrooculogram
Nicotinic and muscarinic mediations
THERE are a number of reports on movement disorders following systemic and intracerebral administration of nicotine and carbachol. The description of these disorders varies from tremors to convulsions. The best evidence for tremor seems to derive from experiments in which nicotine has been administered systemically and carbachol, intracerebrally [ 3, 5, 61. In addition, adynamia was observed after intracerebral administration of carbachol [ 61, while data concerning the effects of nicotine are still missing. Therefore, in the light of these findings, it was of interest to investigate and to compare the effects of carbachol and nicotine on electromyogram after their injections into cerebral ventricles of conscious cats.
ate electrodes to record electromyogram (EMG) of the neck muscle, electrooculogram (EOG) and electroencephalogram (EEG) were also implanted. Postoperatively, penicillin was administered intramuscularly. The animals were kept in an isolated room in individual cages with continuous light and constant temperature. An interval of 7 days elapsed before cats were used for the experiments. Carbachol chloride and nicotine hydrogen tartarate were dissolved in sterile 0.9% sodium chloride. The solutions, warmed to 37°C were injected slowly under aseptic conditions in volumes of 0.1 ml and washed in with 0.1 ml of 0.9% saline. Drug doses refer to the salts. EEG, EOG and EMG were thereafter monitored continuously for 6 hours and segments of the recordings without gross movement artifacts with the animals apparently restful were considered for analysis.
METHOD
Eight adult male and female cats were used in these experiments. For injection of substance into the cerebral ventricles a Collison cannula was implanted aseptically into the left lateral ventricle [ 61 during pentobarbitone sodium anesthesia (35-45 mg/kg, intraperitoneally). The cannula, with a side hole 1 mm from its closed tip, was directed with the opening towards the foramen of Monro. Dye studies indicated that the injected material passed from the lateral ventricle into the third and the fourth ventricles. Appropri-
RESULTS
Carbachol injected in a dose of 2-5 fig into the lateral ventricle of conscious cats produced intense bursts in the EMG consisting of high amplitude and fast frequency activity after a few minutes, followed by small amplitude activity spaced at irregular time intervals (Fig. 1: 1 B). This type of activity lasted up to 6 hr and was maintained during slow wave sleep as well (Fig. 1: 1 C). With small doses of
‘Reprints available from M. RadulovaEki, Department of Pharmacology, University of Illinois at the Medical Center, P.O. Box 6998, Chicago, Illinois, 60680. This research was supported by USPHS Grant 10921 to M. RadulovaEki. ‘D. B. Beleslin is a Visiting Associate Professor from the Department of Pharmacology, Medical Faculty, Beograd, Yugoslavia. 75
BELESLIN.BELLUR AND RADULOVACKI
R.tiippw
Cxx
L-RFr
EMG’=‘dW
8.
EOGc
R. Hippe L-RFrCxx EMG
R. Hipp L-R
Fr Cx EMG
-
# -
I set
FIG. 1. Electroencephalogram (EEG), electromyogram (EMG) and electrooculogram (EOG) of two conscious cats after administration of carbachol(2 pg) and nicotine (2 mg) into the left lateral cerebral ventricle. 1 A, control, lB, 30 min and lC, 5 hr following carbachol, respectively. 2A, control, 2B, 30 min and ZC, 5 hr following nicotine, respectively. R. Hipp. - right hippocampus. L-R Fr Cx ~ left and right frontal cortex. EMG - electromyogram of the neck muscle.
carbachol (0.04-0.1 /IS), this effect was inconsistent. By increasing the doses of carbachol up tg 10 Mg the depression in the EMG was intensified and in some cats adynamia developed. In the dosage range of 0.04-2 peg the animals did not display much by way of autonomic or behavioral changes. In S- 10 fig dose range they displayed intermittent tremulousness, an exaggerated startle response, minimal piloerection, increased bronchial secretions with coughing, and occasional circling behavior. Intermittent periods of adynamia (EMG suppression), lasting from a few seconds to a few minutes, always occurred after enhanced motor activity. With the above described EMG changes these were no overt behavioral or autonomic correlates. Bursts of increased motor activity during wakefulness were also detected in the EOG (Fig. 1: lB1, the intensity depended on the dose of carbachol. Nicotine injected in a dose of 0.04-02 mg into the lateral ventricle of conscious cats produced high amplitude and fast frequency activity in the EMG after a few minutes (Fig. 1 :2Bl. At the same time, bursts of such activity spaced at irregular time intervals were rarely recorded. However, in 4 out of 16 experiments, depression of the amplitude in the EMG developed after a shortlasting increase. This type of activity lasted 3-5 hr and was obtained when nicotine was used in doses from 0.04-2 mg. Adynamia was not observed even when nicotine in a high dose of 2 mg produced convulsions. The EOG activity, comparison with carbachol, was much less stimulated. Increased EOG activity lasted up to 30-40 min and, in general, cats were quiet (Fig. 1:2BI. When nicotine was injected in doses from 0.5-2 mg, mydriasis, ear twitching,
vomiting, respiratory changes, sometimes akathisia and convulsions accompanied the alterations in the EMG only during the first two hour recording period. DISCUSSION
Gross behavioral changes have already been described as have movement disorders and alterations in the body temperature produced by carbachol and nicotine injected into the cerebral ventricles of cats and monkeys [2,6]. However, the results presented here show that carbachol and nicotine altered the EMG activity of conscious cats when injected into the lateral ventricle. Both agents produced high amplitude and fast frequency activity in the EMG, while carbachol caused more bursts of such activity spaced at irregular time intervals accompanied by marked EOG activity. Further, carbachol, but not nicotine, evoked adynamia. Thus it appears that carbachol and nicotine, acting on the structures lining the cerebral ventricles, activate the efferent motor system causing enhancement in the EMG activity. In this context, it is interesting to note that carbachol injected into the caudate nucleus evokes tremor, while nicotine produced no effect [ 41. Tremor, changes in the body temperature, as well as the gross behavioral phenomena which are caused by carbachol administered into the cerebral ventricles or into the caudate nucleus of cats are blocked by atropine or scopolamine. These effects are resistant to ganglionic and neuromuscular blocking agents [ 2,6]. It appears, therefore, that carhachol activates central muscarinic cholinoceptive sites. On the other hand, there is no conclusive evidence concerning the
CARBACHOL,
NICOTINE
77
AND EMG
central nicotinic mediations [3]. Furthermore, there is evidence that the central effects of nicotine may be mediated, at least in part, by release of acetylcholine [ I] If this is the case, then both nicotinic and muscarinic
mediations [3]. The longlasting
could subserve results obtained effect of nicotine
the central effects of nicotine in this study concerning the on EMG favor this view.
REFERENCES Armitage, A. K., G. H. Hall and C. M. Sellers. Effects of nicotine on electrocortical activity and acetylcholine release from the cat cerebral cortex. Er. J. Pharmac. 35: 152-160, 1969. Beleslin, D. B., L. Grbovid and B. Z. RadmanoviC. The pharmacology of gross behavioural effects of cholinomimetic substances injected into the cerebral ventricles of unanaesthetized cats: evidence for central muscarinic mediation. Neuropharmacology 13: 1163-1169, 1974. Brimblecombe, R. W. Drug Actions on Cholinergic Systems. Baltimore, London, Tokyo: University Park Press: 1974, 191-124 p.
4.
5. 6. 7.
Connor, J. D., G. V. Rossi and W. W. Baker. Analysis of the tremor induced by injection of cholinergic agents into the caudate nucleus. ht. J. Neurooharmac. 5: 207-216. 1966. Feldberg, W. A Pharmacolog& Approach to the brain from its Inner and Outer Surface. London: Edward Arnold (Publishers), 1963. Myers, R. D. Handbook of Drug and Chemical Stimulation of the Brain. New York: Van Nostrand Reinhold Company, 1914. Silvette, H., E. C. Hess, P. S. Larson and H. B. Haag. The actions of nicotine on central nervous Pharmac. Rev. 14: 137-173, 1972.
system
functions.
