A long-lasting inward current induced by intracellular injection of calcium ions in identified neurons of Helix pomatia.
Intracellular Ca2+ is known to activate an early unspecific inward and a potassium outward current in various vertebrate and invertebrate preparations. In the identified neurons B1, B2 and B3 of the buccal ganglia of Helix pomatia an intracellular application of Ca2+ induced a late long-lasting inward current besides the currents mentioned. Ca2+ was injected by ionophoresis or pressure pulses. The long-lasting inward current was reversed at membrane potentials of between -30 and -40 mV, whereas the equilibrium potential of the unspecific inward and potassium outward current was in the range of -20 to +10 mV and -50 to -70 mV, respectively. The late inward current was accompanied by an increase of the membrane conductance and suppressed by the Cl- channel blocker 9-anthracencarbonic acid. The equilibrium potential shifted with changes in the extracellular Cl- concentration. The long-lasting inward current is suggested to be activated by intracellular Ca2+ and to be carried by Cl-.
D000818:Animals; D002118:Calcium / Q000494:pharmacology*; D002462:Cell Membrane / Q000187:drug effects; D002712:Chlorides / Q000378:metabolism*; D004553:Electric Conductivity; D005724:Ganglia / Q000187:drug effects*; D006372:Helix, Snails; D066298:In Vitro Techniques; D007473:Ion Channels / Q000187:drug effects*; D008564:Membrane Potentials
D002712:Chlorides; D007473:Ion Channels; D002118:Calcium