ISSN:
1432-2072
Keywords:
Morphine
;
Habituation
;
Precipitated Abstinence Syndrome
;
ACh Release
;
Push-Pull Cannulae
;
Cerebral Cortex
;
Lateral Ventricle
Source:
Springer Online Journal Archives 1860-2000
Topics:
Medicine
Notes:
Abstract The rate of release of central acetylcholine (ACh) was determined in unanaesthetized cats by perfusing the sensorimotor cortex or the lateral ventricles with a neostigmine-containing solution by means of push-pull cannulae. Cats were made physically dependent on morphine over a 10-day schedule of daily increasing doses of the narcotic. No difference in both cortical and ventricular ACh release was noted between these morphine-dependent animals (determined following the last dose of morphine-20 mg/kg i.p.) and the same animals prior to the injection of any morphine. When the abstinence syndrome was precipitated in these habituated animals (0.2 mg/kg of naloxone, i.p.), both cortical and ventricular ACh release was enhanced, coincident with behavioural agitation of the animal. While the behavioural symptoms of the abstinence syndrome persisted, this increased release of ACh was only of short duration. In non-dependent cats, a 1-h localized perfusion of the sensorimotor cortex with a morphine-containing solution (10−4 or 5×10−4 g/ml) had no effect on either cortical ACh release or the behaviour of the animal. These results raise questions concerning the hypothesis that a cholinergic mechanism governs the occurrence of the morphine abstinence syndrome in cats.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1007/BF00421780
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