[Participation of Na/Ca-exchange and intracellular mobilized Ca2+ in regulating depression of cholino-sensitive Helix lucorum neurons to a cellular analog of habituation].
The role the Na/Ca-exchange and intracellular Ca2+ released from Ca(2+)-depots in the modulatory action of Na,K-pump inhibitor ouabain on cholinosensitivity in the command neurons of Helix lucorum was studied in a cellular analogue of habituation. The integral transmembrane inward currents in LPa2, LPa3, RPa3, and RPa2 neurons were recorded in Helix lucorum ganglia preparation using two-electrode voltage clamp technique. The reduction of cholinosensitivity of a neuron was estimated as a depth of the depression of the acetylcholine-induced inward currents during the rhythmic local acetylcholine applications (with the interstimulus interval of 2-4 min) on a somatic membrane. The inhibitor of the Na/Ca-exchange benzamil (the extracellular action, 15-35 mcM) and two specific inhibitors of Ca-ATPase in the sarcoplasmic and endoplasmic reticulum, cyclopiazonic acid and thapsigargin (intracellular injection by spontaneous diffusion, 0.1 mM) prevented the modification of the depression of acetylcholine-induced current by ouabain (100 mcM) during the rhythmic application of acetylcholine. A conclusion is drawn that the inhibitor of the Na,K-pump ouabain modifies the depression of neuron cholinosensitivity in the cellular analogue of habituation via the Na/Ca-exchange and intracellular Ca2+ released from Ca2+ depots.
Pivovarov
A S
AS
Lomonosov State University, Moscow.
Nistratova
V L
VL
Boguslavskiĭ
D V
DV
D000109:Acetylcholine / Q000008:administration & dosage; D000584:Amiloride / Q000031:analogs & derivatives* / Q000494:pharmacology; D000818:Animals; D002118:Calcium / Q000502:physiology*; D004791:Enzyme Inhibitors / Q000494:pharmacology; D006372:Helix, Snails / Q000502:physiology*; D009474:Neurons / Q000378:metabolism / Q000502:physiology*; D011950:Receptors, Cholinergic / Q000378:metabolism; D019831:Sodium-Calcium Exchanger / Q000502:physiology*; D000254:Sodium-Potassium-Exchanging ATPase / Q000037:antagonists & inhibitors / Q000502:physiology*
D004791:Enzyme Inhibitors; D011950:Receptors, Cholinergic; D019831:Sodium-Calcium Exchanger; C013407:benzamil; D000584:Amiloride; D000254:Sodium-Potassium-Exchanging ATPase; D000109:Acetylcholine; D002118:Calcium