Effects of Win 55,212-2 on hippocampal CA1 long-term potentiation in experiments controlled for basal glutamatergic synaptic transmission

Cannabinoids, the active components of marijuana, are presumed to affect memory by an action on long-term potentiation. However, these molecules also reduce hippocampal glutamatergic neurotransmission. To distinguish the two activities, we studied the effects of the synthetic cannabinoid (R)-(+)-[2,3-Dihydro-5-methyl-3-(4-morpholinylmethyl)pyrrolo-[1,2,3-de]- 1,4-benzoxazin-6-yl]-1-naphtalenylmethanone (Win 55,212-2, 10 μM) on CA1 hippocampal responses generated by the activation of two independent pathways, one of which was potentiated with a tetanic stimulation. The results of the study show the following: (a) the drug does not affect long-term potentiation provided that the responses are compared to those obtained in the unpotentiated control pathway; (b) Win 55,212-2 increases post-tetanic potentiation. © 2002 Elsevier Science B.V. All rights reserved.