Effect of Intracerebroventricular [IVT] administration of endogenous opoids morphine on brain acetyl-choline release in rats

ABSTRACT

In the present study, female Wistar albino rats were employed as experimental animals. Acetylcholine [Ach] release was collected with the help of collecting cups placed on the cortex every five minuties. Collection was started 30 minutes prior to i. v. t. administration of test drug and continued for 120 minutes. Ach was bioassayed on leech muscle preparation. It was observed that morphine, beta-endorphin, etorphine and met - enkephalin ub decreased the Ach release. Morphine and beta-endorphin showed most potent effect while met - enkephalin had a minimum effect on Ach release. Etorphine induced inhibition was of a transient nature. Leu - enkephalin did not show any inhibitory effect on Ach release. Naloxone administration, 30 minutes after beta-endorphin, reversed the inhibitory effect on Ach release to pre - drug level