In vivo presynaptic modulation of serotonergic neurotransmission in the rat hippocampus by diazepam.
The effect of the benzodiazepine agonist, diazepam, on serotonergic (5-HT) neurotransmission was assessed in in vivo electrophysiological experiments. Diazepam enhanced, in a dose-dependent manner (0.05-2 mg/kg i.v.), the effect of electrical stimulation of the ascending 5-HT pathway on the firing activity of dorsal hippocampus pyramidal neurons. This effect was blocked by the benzodiazepine antagonist, flumazenil. Diazepam did not modify the efficacy of microiontophoretic application of 5-HT and GABA. The results indicate that the activation of benzodiazepine receptors facilitates of 5-HT neurotransmission, presumably through a presynaptic modulatory mechanism.
Lista
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McGill University, Department of Psychiatry, Montreal, Quebec, Canada.
Blier
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De Montigny
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D000818:Animals; D003975:Diazepam / Q000494:pharmacology*; D004558:Electric Stimulation; D004594:Electrophysiology; D006624:Hippocampus / Q000187:drug effects*; D007478:Iontophoresis; D008297:Male; D051381:Rats; D011919:Rats, Inbred Strains; D012701:Serotonin / Q000502:physiology*; D013569:Synapses / Q000187:drug effects*; D009435:Synaptic Transmission / Q000187:drug effects*
D012701:Serotonin; D003975:Diazepam