Blocking effect of La3+ ions on transmembrane ionic current evoked by intracellular cyclic AMP injection in identified Helix pomatia neurons.
Using the fluorescent probe fura-2 for measurements of the cytoplasmic concentration of free Ca2+ ions [( Ca]in) in combination with conventional current- or voltage-clamp methods, we studied the effects of La3+ ions on the cellular responses evoked by intracellular cAMP (adenosine 3',5'-cyclic monophosphate) injections into isolated Helix pomatia neurons. La3+ ions in submillimolar concentrations decreased cAMP-evoked [Ca]in transients. Transmembrane ionic currents evoked by cAMP injections were completely blocked by La3+ ions (1.0 mM) in all neurons under investigation. La(3+)-induced effects essentially differ from each other in RPa1 (right parietal 1) and LPa3 (left parietal 3) neurons. La3+ ions in milli- and submillimolar concentrations strongly affect different subcellular systems, especially, those which regulate an intracellular calcium concentration.
Belan
P V
PV
Department of General Physiology of Nervous System, Ukrainian Academy of Sciences, Kiev, U.S.S.R.
Osipenko
O
O
D000818:Animals; D002104:Cadmium / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D015220:Calcium Channels / Q000187:drug effects*; D000252:Calcium-Transporting ATPases / Q000378:metabolism; D000242:Cyclic AMP / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D006372:Helix, Snails; D015640:Ion Channel Gating / Q000187:drug effects*; D007811:Lanthanum / Q000494:pharmacology*; D008564:Membrane Potentials / Q000187:drug effects; D009474:Neurons / Q000187:drug effects* / Q000502:physiology; D015221:Potassium Channels / Q000187:drug effects
D015220:Calcium Channels; D015221:Potassium Channels; D002104:Cadmium; D007811:Lanthanum; D000242:Cyclic AMP; D000252:Calcium-Transporting ATPases; D002118:Calcium