Journal of physiology and pharmacology : an official journal of the Polish Physiological Society
-
J. Physiol. Pharmacol. · Oct 2011
5-HT7 receptors modulate GABAergic transmission in rat hippocampal CA1 area.
The effects of the activation of serotonin-7 (5-HT(7)) receptors were investigated in the CA1 area pyramidal cells and stratum radiatum fast spiking GABAergic interneurons of rat hippocampal slices. To activate 5-HT(7) receptors, 5-carboxamidotryptamine (5-CT), a nonselective 5-HT(1A)/5-HT(7) agonist, was applied in the presence of N-[2-[4-(2-methoxyphenyl)-1piperazinyl]ethyl]-N-2-pyridinylcyclohexanecarboxamide (WAY 100635), a selective 5-HT(1A) receptor antagonist. The activation of 5-HT(7) receptors resulted in a dose-dependent increase in the mean frequency of spontaneous inhibitory postsynaptic currents (sIPSCs) recorded from pyramidal neurons while the mean amplitude of sIPSCs remained unaltered. ⋯ These data suggest that the activation of 5-HT(7) receptors results in an enhancement of the GABAergic transmission in the hippocampal CA1 area via two mechanisms. The first one involves an enhancement of excitatory glutamatergic input to GABAergic interneurons and is likely to be mediated by presynaptic 5-HT(7) receptors. The second effect, most likely related to the activation of 5-HT(7) receptors located on interneurons, results in an enhancement of the release of GABA.