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.
Koike
H
H
Department of Chemical Pharmacology, Faculty of Pharmaceutical Sciences, University of Tokyo, Japan.
Saito
H
H
Matsuki
N
N
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