Effects of organic Ca2+-antagonists on membrane characteristics of nodose ganglion cells in the rabbit.
The effects of Ca2+-antagonists, diltiazem, verapamil and nifedipine on excised and superfused nodose ganglia of the rabbit were investigated with intracellular recording techniques. In a Na-free solution, somata of nodose ganglion C-cells were capable of eliciting Ca-spikes which were maintained by a Ca-influx when stimulated by passing currents. At a concentration of 10(-5) M, spike amplitude was inhibited to 24% of control by diltiazem, to 16% by verapamil, and to 13% by nifedipine. In a normal physiological solution, diltiazem at 10(-6) M, verapamil at 10(-6) M, and nifedipine at 10(-7) M reduced the maximal rate of rise and at 10(-7) M produced a reduction of the maximal rate of fall of the action potentials accompanied with a prolonged duration, although the resting membrane potential and the amplitude of the action potentials were not altered. The results reveal membrane characteristics of ganglion cells and suggest that Ca2+-antagonists depress not only Ca-influx but also Na-influx and K-efflux.
D000200:Action Potentials / Q000187:drug effects; D000818:Animals; D001692:Biological Transport / Q000187:drug effects; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology*; D002462:Cell Membrane / Q000502:physiology / Q000648:ultrastructure; D004110:Diltiazem / Q000494:pharmacology; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects; D009543:Nifedipine / Q000494:pharmacology; D009620:Nodose Ganglion / Q000166:cytology / Q000187:drug effects* / Q000502:physiology; D011188:Potassium / Q000378:metabolism; D011817:Rabbits; D014630:Vagus Nerve / Q000187:drug effects*; D014700:Verapamil / Q000494:pharmacology
D002121:Calcium Channel Blockers; D014700:Verapamil; D004110:Diltiazem; D009543:Nifedipine; D011188:Potassium; D002118:Calcium