Activity-dependent enhancement of miniature excitatory postsynaptic current amplitude and its modulation by protein kinase C in cultured rat sympathetic neurons.
A high K+ solution increased the frequency of miniature excitatory postsynaptic currents (MEPSCs) and intracellular Ca2+ concentration ([Ca2+]i) in cultured rat sympathetic neurons. Repetition or continuation of high K+ treatment increased MEPSC amplitude, acetylcholine-induced currents and the averaged rise in [Ca2+]i per single MEPSC. The enhancement of MEPSCs lasted over 30 min and was inhibited by intracellular BAPTA and phorbol ester, but not by atropine. The results suggest that repeated Ca2+ entry through the channel pore of nicotinic acetylcholine receptor enhances the efficacy of its opening and the activation of protein kinase C inhibits the enhancement.
Liu
C
C
Department of Physiology, Saga Medical School, Japan.
Shirasaki
T
T
Tanaka
S
S
Kuba
K
K
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D002118:Calcium / Q000378:metabolism; D002478:Cells, Cultured; D004533:Egtazic Acid / Q000031:analogs & derivatives / Q000494:pharmacology; D019706:Excitatory Postsynaptic Potentials / Q000187:drug effects; D007700:Kinetics; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D015240:Phorbol 12,13-Dibutyrate / Q000494:pharmacology; D010703:Phorbol Esters / Q000494:pharmacology; D011188:Potassium / Q000494:pharmacology; D011493:Protein Kinase C / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar; D017783:Superior Cervical Ganglion / Q000166:cytology / Q000502:physiology*; D013569:Synapses / Q000187:drug effects / Q000502:physiology*
D010703:Phorbol Esters; C008876:phorbol-12,13-didecanoate; D015240:Phorbol 12,13-Dibutyrate; D004533:Egtazic Acid; D011493:Protein Kinase C; C025603:1,2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid; D000109:Acetylcholine; D011188:Potassium; D002118:Calcium