Extrusion of calcium from a single isolated neuron of the snail Helix pomatia.
Simultaneous optical measurements of extra- and intracellular Ca2+ concentrations were carried out on isolated snail neurons injected iontophoretically with Ca2+. The fluorescent indicator Fura-2 was used to measure intracellular concentration of free Ca, and the absorbant indicator Antipyrylazo III to measure changes in extracellular calcium concentration in the micro-chamber containing the cell. The velocity of Ca2+ extrusion from a single cell has been shown to be in accordance with the level of free Ca in the neuronal cytoplasm. After an increase in intracellular free Ca by iontophoretic injection from a microeletrode to 0.2-0.5 microM, the velocity of Ca2+ extrusion from the neuron was approximately 0.3-4.6 microM/sec per cell volume. During caffeine-induced calcium-dependent calcium release of Ca2+ from intracellular stores a stimulation of calcium extrusion took place, reaching the velocity of 5.0 microM/sec per cell volume.
Tepikin
A V
AV
Department of General Physiology of Nervous System, A.A. Bogomoletz Institute of Physiology, USSR.
Kostyuk
P G
PG
Snitsarev
V A
VA
Belan
P V
PV
D000818:Animals; D002110:Caffeine / Q000494:pharmacology; D002118:Calcium / Q000032:analysis* / Q000378:metabolism*; D016257:Fura-2 / Q000737:chemistry; D006372:Helix, Snails / Q000378:metabolism; D008564:Membrane Potentials; D009282:Naphthalenesulfonates / Q000737:chemistry; D009474:Neurons / Q000187:drug effects / Q000378:metabolism*
D009282:Naphthalenesulfonates; D002110:Caffeine; C016238:antipyrylazo III; D002118:Calcium; D016257:Fura-2