ATP-sensitive K+ channel activators suppress the GABAergic inhibitory transmission by acting on both presynaptic and postsynaptic sites in rat cultured hippocampal neurons.
Effects of ATP-sensitive K+ (KATP) channel activators on the inhibitory transmission were explored by applying the patch-clamp technique to both presynaptic and postsynaptic hippocampal neurons prepared from neonatal rats. Diazoxide (0.5 mM) and cromakalim (0.5 mM) reduced GABAergic synaptic currents to 57 and 81% of control, respectively, and reduced the currents induced by exogenously applied GABA (10 microM) to 74 and 95% of control, respectively. These results suggest that KATP channel activators suppress the GABAergic transmission partly by reducing the GABA release and partly by affecting the postsynaptic GABA response.
Ohno-Shosaku
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Department of Physiology, Faculty of Medicine, Kanazawa University, Ishikawa, Japan.
Sawada
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Yamamoto
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D000200:Action Potentials / Q000187:drug effects; D000255:Adenosine Triphosphate / Q000494:pharmacology*; D000818:Animals; D000831:Animals, Newborn; D001578:Benzopyrans / Q000494:pharmacology; D002478:Cells, Cultured; D019806:Cromakalim; D003981:Diazoxide / Q000494:pharmacology; D006624:Hippocampus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D009474:Neurons / Q000187:drug effects / Q000378:metabolism; D015221:Potassium Channels / Q000187:drug effects / Q000378:metabolism*; D011758:Pyrroles / Q000494:pharmacology; D051381:Rats; D017661:Receptors, Presynaptic / Q000187:drug effects*; D013569:Synapses / Q000187:drug effects; D009435:Synaptic Transmission / Q000187:drug effects*; D005680:gamma-Aminobutyric Acid / Q000502:physiology*
D001578:Benzopyrans; D015221:Potassium Channels; D011758:Pyrroles; D017661:Receptors, Presynaptic; D019806:Cromakalim; D005680:gamma-Aminobutyric Acid; D000255:Adenosine Triphosphate; D003981:Diazoxide