title: Effects of delta 9-tetrahydrocannabinol on sensory-evoked discharges of granule cells in the dentate gyrus of behaving rats.
abstract: Extracellular action potentials were recorded from identified cells in the dentate gyrus of the awake freely moving rat during performance of a two-tone discrimination task. The effects of low doses of delta 9-tetrahydrocannabinol (delta 9-THC) were assessed on the firing patterns of granule cells to the tone stimuli. Intraperitoneal injections of delta 9-THC at 1.0 and 2.0 mg/kg, but not 0.5 mg/kg, produced a significant suppression of granule cell activity lasting up to 4 hr. This suppression was present in both the spontaneous (pretone) activity and tone-evoked responses of granule cells. The tone responses of cells recorded from the inferior colliculus were unaffected by THC injection at 1.0 and 2.0 mg/kg, implicating further the hippocampus as a site of specific action of delta 9-THC. In the preceding paper it was demonstrated that such doses produced both impairment of discrimination behavior and modifications of sensory-evoked potentials recorded from the dentate gyrus. However, the influence of delta 9-THC on cell firing in the dentate gyrus was more severe both in magnitude and duration of suppression than were the effects on behavior and on sensory-evoked potentials.
mesh_terms: D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects*; D013759:Dronabinol / Q000494:pharmacology*; D005073:Evoked Potentials, Somatosensory / Q000187:drug effects*; D006624:Hippocampus / Q000166:cytology* / Q000187:drug effects; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D013997:Time Factors
chemical_list: D013759:Dronabinol