Effects of delta-9-tetrahydrocannabinol on sensory evoked hippocampal activity in the rat: principal components analysis and sequential dependency.
The effects of delta-9-tetrahydrocannabinol (delta-9-THC) were assessed on identified hippocampal sensory evoked potentials obtained from rats during performance of a two-tone discrimination task. Techniques which analyzed the trial-to-trial sequential and serial dependence underlying the variance in evoked potential amplitude were utilized. Waveforms of averaged tone-evoked potentials (AEPs) recorded from the outer molecular layer of the dentate gyrus (OM) were subjected to principal components analysis which revealed eight principal components accounting for 90.3% of the total variance in the set of OM AEP waveforms. Five of the eight components were altered significantly in comparison to vehicle injection sessions after administration of either a 1.0- or 2.0-mg/kg dose of delta-9-THC. These alterations accounted for the amplitude and latency changes in the OM AEP described in a previous report. In addition, delta-9-THC also disrupted the trial-to-trial sequential dependency of the OM AEPs. An important result showed that delta-9-THC selectively influenced the serial dependence of the OM AEP. These results implicate delta-9-THC as a potent disruptor of temporally specific information as it is processed by the hippocampus and suggest that such disruption may be the basis of delta-9-THC effects on memory processes in humans.
Hampson
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Department of Physiology and Pharmacology, Bowman Gray School of Medicine of Wake Forest University, Winston-Salem, North Carolina.
Foster
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TC
Deadwyler
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SA
D000818:Animals; D013759:Dronabinol / Q000494:pharmacology*; D005071:Evoked Potentials / Q000187:drug effects*; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D008297:Male; D008568:Memory / Q000187:drug effects; D051381:Rats; D011919:Rats, Inbred Strains; D012677:Sensation
D013759:Dronabinol