Delta 9-tetrahydrocannabinol impairs spatial memory through a cannabinoid receptor mechanism
The purpose of the present study was to investigate whether the cannabinoid and cholinergic systems impair working memory through a common mechanism. This hypothesis was tested by examining whether the cannabinoid antagonist SR141716A would ameliorate radial-arm performance deficits caused by either...
Saved in:
Published in | Psychopharmacology Vol. 126; no. 2; p. 125 |
---|---|
Main Authors | , |
Format | Journal Article |
Language | English |
Published |
Germany
01.07.1996
|
Subjects | |
Online Access | Get more information |
Cover
Loading…
Summary: | The purpose of the present study was to investigate whether the cannabinoid and cholinergic systems impair working memory through a common mechanism. This hypothesis was tested by examining whether the cannabinoid antagonist SR141716A would ameliorate radial-arm performance deficits caused by either the naturally occurring cannabinoid, delta 9-THC, or scopolamine, a muscarinic antagonist. In addition, we evaluated whether the cholinesterase inhibitor, physostigmine, would prevent delta 9-THC-induced impairment of spatial memory. Finally, because the locomotor suppressive effects of cannabinoids may decrease radial arm choice accuracy independent of a direct effect on memory, we examined the impact of increasing the intertrial error on radial arm choice accuracy. As previously reported, delta 9-THC impaired maze performance (ED50 = 3.0 mg/kg). Increasing the intertrial interval from 5 s to 30 s resulted in a three-fold increase in the amount of time required to complete the maze without affecting choice accuracy. Importantly, SR141716A prevented delta 9-THC-induced deficits in radial-arm choice accuracy in a dose-dependent manner (AD50 = 2.4 mg/kg); however, the cannabinoid antagonist failed to improve the disruptive effects of scopolamine. Conversely, physostigmine failed to improve performance deficits produced by delta 9-THC. These data provide strong evidence that delta 9-THC impairs working memory through direct action at cannabinoid receptors. Moreover, these results suggest that scopolamine and delta 9-THC do not impair spatial memory in a common serial pathway, though they may converge on a third neurochemical system. |
---|---|
ISSN: | 0033-3158 |