Inhibitory effect of aniracetam on N-type calcium current in acutely isolated rat neuronal cells.
Effects of aniracetam on whole-cell calcium currents were studied in acutely isolated neuronal cells from postnatal rat ventromedial hypothalamus. There were three types of inward calcium currents, one low-threshold transient current and two high-threshold sustained currents. The nicardipine sensitive L-type current was activated at -20 mV or more depolarized potentials, and the omega-conotoxin sensitive N-type current was recorded at more positive potentials than the L-type. Aniracetam inhibited the N-type current in a dose-dependent manner without affecting the other two types of calcium currents. The effect appeared soon after the addition and lasted for several minutes during washing. Since the N-type current is thought to regulate the release of transmitters, the inhibitory effect may contribute to the nootropic property of aniracetam by modifying the neurotransmission.
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
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H
Koike
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H
Saito
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N
Matsuki
D000818:Animals; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D004566:Electrodes; D004594:Electrophysiology; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*; D010455:Peptides / Q000494:pharmacology; D011760:Pyrrolidinones / Q000494:pharmacology*; D051381:Rats; D009435:Synaptic Transmission / Q000187:drug effects; D014697:Ventromedial Hypothalamic Nucleus / Q000166:cytology / Q000187:drug effects / Q000378:metabolism; D020960:omega-Conotoxins
D002121:Calcium Channel Blockers; D010455:Peptides; D011760:Pyrrolidinones; D020960:omega-Conotoxins; C053423:Conus magus toxin; C036466:aniracetam