The effect of acetylcholine and serotonin on calcium transients and calcium currents in identified Helix pomatia L. neurons.
The results presented demonstrate that in D neurons of the snail Helix pomatia L., acetylcholine (ACh) (10 divided by 100 microM) and serotonin (5-HT) (0.1 divided by 1000 microM) applications reduce both the basal intracellular concentration level ([Ca2+]in) and the amplitudes of calcium transients induced by membrane depolarization. It is likely that the mechanism of [Ca2+]in changes in the suppression of calcium inward currents (ICa). Influences of Ach and 5-HT on ICa were studied. Both effects were dose-dependent (ACh--0.01 divided by 100 microM and 5-HT--0.1 divided by 1000 microM). The half-maximal effects (IC50) were evoked by ACh concentration of 0.15 microM and 5-HT--15 microM. Furthermore we have also shown that in some cells 5-HT could evoke a transient increase in ICa (IC50 = 2 microM). The effects of Ach and 5-HT were nonadditive--the subsequent application of ACh after 5-HT, and vice versa, produced no inhibitory effects. This may indicate that both substances act through a common intermediate (possibly, G-protein).
Belan
P V
PV
Department of General Physiology of Nervous System, A. A. Bogomoletz Institute of Physiology, Ukrainian Academy of Sciences, Kiev.
Kiss
T
T
Snitsarev
V
V
Storozhuk
M V
MV
Osipenko
O N
ON
D000109:Acetylcholine / Q000494:pharmacology*; D000818:Animals; D002118:Calcium / Q000502:physiology*; D002462:Cell Membrane; D004305:Dose-Response Relationship, Drug; D004338:Drug Combinations; D016257:Fura-2; D006372:Helix, Snails; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects / Q000502:physiology*; D012701:Serotonin / Q000494:pharmacology*
D004338:Drug Combinations; D012701:Serotonin; D000109:Acetylcholine; D002118:Calcium; D016257:Fura-2