Spontaneous unit activity in the globus pallidus following cumulative injections of morphine in phenobarbital- or chloral hydrate-anesthetized rats.
The effect of systemically administered morphine on spontaneous unit activity, recorded from the globus pallidus, was evaluated in this study. A wide range of doses of morphine was administered in order to characterize the influences of morphine on pallidal activity in a dose-related manner. Two separate studies were conducted. In the first study, a semichronic preparation, lightly anesthetized with phenobarbitol, was used. Acutely prepared, chloral hydrate-anesthetized rats were utilized in the second experiment. With phenobarbital, morphine caused a significant reduction in pallidal activity in 75% of the cells recorded, whereas only 45% of the pallidal cells responded similarly to injection of morphine in chloral hydrate-anesthetized animals. However, the dose of morphine required to decrease unit activity was substantially less with chloral hydrate than with phenobarbital anesthesia.
D000200:Action Potentials / Q000187:drug effects; D000758:Anesthesia; D000818:Animals; D002697:Chloral Hydrate / Q000494:pharmacology*; D005917:Globus Pallidus / Q000187:drug effects*; D008297:Male; D009020:Morphine / Q000494:pharmacology*; D009270:Naloxone / Q000494:pharmacology; D010634:Phenobarbital / Q000494:pharmacology*; D051381:Rats; D011919:Rats, Inbred Strains
D009270:Naloxone; D002697:Chloral Hydrate; D009020:Morphine; D010634:Phenobarbital