The effect of selective inhibition of pseudocholinesterase on the spontaneous and evoked activity of the cat's cerebral cortex

Desmedt, Jean Edouard; Grutta, G. La

doi:10.1113/jphysiol.1957.sp005741

Cited by 77 publications

(12 citation statements)

References 35 publications

(34 reference statements)

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“…They concluded that there was no significant attenuation of the volley of acoustic im pulses up to their arrival in the thalamus. The findings in the present experiments that the collicular acoustic evoked potential was stable in the arousal state and was not activated by any doses of the central depressants could serve to support the conclusion by Desmedt et al (20,21) and to explain the facilitatory effect of small doses of pento barbital sodium, chloralose and presumedly chlorpromazine on the transmission mecha nism in the supra-thalamic level.…”

Section: Methodssupporting

confidence: 89%

“…On the other hand, Desmedt et al (20) threw doubt upon the inference presented by Hernandez-Peon et al from their electro-anatomical studies on the corticofugal system from the temporoinsular cortex to the cochlear nucleus . They found that the cochlear nucleus response to a standard sound was not affected by faradization of the reticular core of the brain stem and it was suppressed only by stimulation of a more laterally situated and very circumscribed system which was apparently constituted of the descending fibers.…”

Section: Methodsmentioning

confidence: 96%

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Effects of Central Depressants on the Evoked Potentials in the Inferior Colliculus Caused by Acoustic Stimuli in the Cat

Nakai

Takaori

Shimamoto

1965

Japanese Journal of Pharmacology

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It has been well-known that the electrical activity of the central nervous system is facilitated by relatively lower doses of central depressants.Many reports were presented to support the facilitatory mechanism in the brain of exprimental animals at lower dose levels of barbiturates : lowering of stimulation threshold for the recruiting response by King (1) and' Domino (2), increase in amplitude of the somatosensory evoked poten tial recorded from the internal capsule by King et al. (3), and increase in amplitude of the evoked potential recorded from the auditory cortex by Pradhan and Galambos (4).Nakai (5) and Nakai and Takaori (6) showed that pentobarbital sodium, chloralose and chlorpromazine increased the magnitude of the cortical potential evoked by click stimuli and accelerated the manifestation of the ensuing rhythmic after-discharges, while urethane and ethyl alcohol even in small doses reduced the amplitude of the evoked potential.The role of the inferior colliculus as a relay nucleus for the auditory pathway was investigated electrophysiologically by Ades and Brookhart (7) and Thurlow et al. (8).However, there is scarcely any systematic study concerning the effects of central depres sants on the evoked potential in the inferior colliculus. It is considered that the effect of central depressants on the collicular acoustic potential may differ from that on the cortical one. The difference may give some clue for the elucidation of the central audi tory mechanism. METHODSAll experiments were performed in a sound-proof room maintained at the tempera ture of 27°C using cats weighing 2.0 to 3.5 kg. Under ether anesthesia the exposed trachea was intubated and the head of animal was fixed on the stereotaxic instru ment of Todai-Noken type.The left occipital skull covering the cerebrum and cerebellum was , removed, and the left tentorium cerebelli was carefully resected. The left inferior colliculus was exposed for insertion of the recording electrode under direct inspection. The cerebral and cerebellar corticies were not removed. Thereafter, the spinal cord was sectioned at the level of C1 (encephale isole preparation) and the animal was maintained by artificial respiration. A monopolar insulated silver electrode, about

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Section: Methodssupporting

confidence: 89%

Section: Methodsmentioning

confidence: 96%

Effects of Central Depressants on the Evoked Potentials in the Inferior Colliculus Caused by Acoustic Stimuli in the Cat

Nakai

Takaori

Shimamoto

1965

Japanese Journal of Pharmacology

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“…Easier penetration or firmer attachment of neostigmine would also explain why the acetylcholine output rises more steeply on prolonged perfusion with neostigmine than with eserine. Desmedt and La Grutta (1957) suggested that the arousal reaction of the sleeping brain produced in the encephate isoli by carotid injections of anticholinesterases was related to inactivation of pseudocholinesterase rather than to inactivation of true cholinesterase in the brain, because selective inhibitors of pseudocholinesterase were more effective than those of true cholinesterase. The finding that on perfusion with neostigmine instead of eserine the output of acetylcholine was greater cannot be explained on these lines because neostigmine is a less potent inhibitor of pseudocholinesterase than eserine.…”

Section: Discussionmentioning

confidence: 99%

Perfusion of Cerebral Ventricles: Assay of Pharmacologically Active Substances in the Effluent From the Cisterna and the Aqueduct

Bhattacharya

Feldberg

1958

British Journal of Pharmacology and Chemotherapy

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In cats under chloralose anaesthesia the cerebral ventricles were perfused from a cannula in the lateral ventricle. The effluent was collected either from the cisterna or from the aqueduct. When acetylcholine was added to the perfusion fluid and its destruction was prevented by the addition of an anticholinesterase, its recovery in the internal effluent was incomplete and irregular. This could be explained mainly by the devious route the perfusion fluid had to take in order to reach the cisterna and the unavoidable mixture with the cerebrospinal fluid of the subarachnoidal space. When collection was from the aqueduct 90% or more of the acetylcholine added to the perfusion fluid was recovered. In the presence of an anticholinesterase in the perfusion fluid, acetylcholine appeared in the effluent. Neostigmine was more effective than eserine or dyflos. The acetylcholine originated mainly from structures lining the lateral and third ventricle because the amounts in the effluent from the aqueduct were only a little less than those in the cisternal effluent. 'When injected intravenously, eserine was found to pass more readily into the perfusion fluid than neostigmine, probably because eserine passes the blood-brain barrier more readily than neostigmine. The method provides a quantitative approach for the study of the bloodbrain barrier for pharmacologically active substances.Experiments in which the cerebral ventricles of the anaesthetized cat were perfused from the lateral ventricles and the outflow was collected either from the cannulated cisterna magna or from the cannulated aqueduct were described by Bhattacharya and Feldberg (1958b). Perfusate collected from the cisterna had traversed the lateral, third and fourth ventricles and part of the subarachnoidal space; perfusate collected from the aqueduct had passed through the lateral and third ventricles only. Drugs injected intravenously affected the outflow from the two points of collection in different ways. In the present experiments the two methods of perfusion have been used to examine the following problems.(1) What happens to substances added to the perfusion fluid ? Can they be fully recovered in the effluent ? The two substances examined were acetylcholine and histamine. (2) Does acetylcholine appear in the effluent when the ventricles are perfused with Locke solution containing an anticholinesterase or when an anticholinesterase is injected into the blood stream ? (3) Do anticholinesterases injected into the blood stream pass into the perfusion fluid ? METHODSThe experiments were performed on cats anaesthetized intravenously with chloralose. The method of perfusion of the cerebral ventricles and the collection of the effluent from the cisterna or aqueduct was that described by Bhattacharya and Feldberg (1958b).In experiments in which acetylcholine or histamine was added to the perfusion fluid in order to determine their recovery in the effluent, perfusion with the substances was allowed to proceed for about 20 min. before the first sample for assay was col...

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“…There is even the possibility that the pseudo-cholinesterase plays a part in the destruction of the ACh at the site of its release during neuronal activity. This possibility is suggested by the findings ofDesmedt & La Grutta (1957) that selective inhibitors of pseudo-cholinesterase in minute doses will produce the 'alerting reaction' in the isolated cat cerebral cortex. SUMMARY 1.…”

Section: Discussionmentioning

confidence: 99%

Histochemical demonstration of cholinesterases in the hypothalamus of the dog

Abrahams¹,

Koelle²,

Smart³

1957

The Journal of Physiology

102

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In the experiments to be described a histochemical study has been made of the distribution of true and pseudo-cholinesterase in the hypothalamus of the dog. There is considerable evidence to indicate that cholinergic neurones are involved in the release of neurohypophyseal hormones. Pickford (1939) showed that the intravenous injection of acetylcholine (ACh) produced antidiuresis in atropinized dogs, and that this antidiuresis was reduced or abolished by surgical removal of the posterior lobe of the pituitary. She therefore concluded that the ACh caused release of the antidiuretic hormone. Later experiments (Pickford, 1947;Duke, Pickford & Watt, 1950) showed that the ACh most probably acted on the neurones of the hypothalamus, since injections of ACh, as well as anticholinesterases, into the supraoptic nuclei, produced antidiuresis in chloralosed dogs, but only as long as the posterior lobe of the pituitary was intact. The injection of the irreversible anticholinesterase, diisopropylfluorophosphate (DFP), into the supraoptic nucleus produced immediate antidiuresis followed by prolonged polyuria. This prolonged polyuria was attributed to permanent paralysis of neurones resulting from local excess of ACh.There is some evidence that the neurones concerned with the release of oxytocin are also cholinergic, since the injection of DFP into the supraoptic nucleus increases spontaneous uterine activity (Abrahams & Pickford, 1956

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The effect of selective inhibition of pseudocholinesterase on the spontaneous and evoked activity of the cat's cerebral cortex

Cited by 77 publications

References 35 publications

Effects of Central Depressants on the Evoked Potentials in the Inferior Colliculus Caused by Acoustic Stimuli in the Cat

Effects of Central Depressants on the Evoked Potentials in the Inferior Colliculus Caused by Acoustic Stimuli in the Cat

Perfusion of Cerebral Ventricles: Assay of Pharmacologically Active Substances in the Effluent From the Cisterna and the Aqueduct

Histochemical demonstration of cholinesterases in the hypothalamus of the dog

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