title: Blockade of tetanic- and calcium-induced long-term potentiation in the hippocampal slice preparation by neuroleptics.
abstract: The effect of neuroleptics which block calmodulin was studied on two forms of long-term potentiation of field responses evoked by stratum radiatum stimulation of the CA1 region in the in vitro preparation of hippocampal slices. Tetanic stimulation or brief exposure to 4 mM Ca2+ produced a long-lasting augmentation of the extracellular excitatory postsynaptic potentials EPSP) and of the responses of the population spikes. Both forms of potentiation were inhibited by perfusion of 10 microM trifluoperazine (TFP) or pimozide, an effect which is unlikely to involve interactions with dopamine or norepinephrine receptors, but rather a potent blockade of calmodulin-mediated events. The results suggest that induction of the "permanency" of both tetanic- and calcium-induced long term potentiation requires activation of calmodulin and involves some calmodulin-mediated mechanism(s).
mesh_terms: D000818:Animals; D014150:Antipsychotic Agents / Q000494:pharmacology*; D002118:Calcium / Q000494:pharmacology*; D002147:Calmodulin / Q000502:physiology; D004558:Electric Stimulation; D006624:Hippocampus / Q000187:drug effects* / Q000502:physiology; D066298:In Vitro Techniques; D008297:Male; D010868:Pimozide / Q000494:pharmacology; D051381:Rats; D011919:Rats, Inbred Strains; D014268:Trifluoperazine / Q000494:pharmacology
chemical_list: D014150:Antipsychotic Agents; D002147:Calmodulin; D010868:Pimozide; D014268:Trifluoperazine; D002118:Calcium