On the origin of a sustained increase in cytosolic Ca2+ concentration after a toxic glutamate treatment of the nerve cell culture.
A sustained increase of cytosolic Ca2+ concentration, [Ca2+]i, (Ca2+ plateau) was induced by a 15-min treatment with 50 microM glutamate of cultured cerebellar granule cells and hippocampal neurons in a Mg(2+)-free solution. Plateau proved to be insensitive to inhibition of Na+o/Ca2+i exchange caused by removal external Na+ in the post-glutamate period. A approximately 10(5)-fold reduction of [Ca2+]o (from 1.5 mM to 20 nM) in the post-glutamate period caused in most cells only a slow and small decrease in [Ca2+]i, although the same low-Ca2+ trial before glutamate treatment caused in hippocampal cells very quick blockade of spontaneous [Ca2+]i oscillation and a decrease in the basal [Ca2+]i. The results suggest that the Ca2+ plateau is due to a suppression of the Ca2+ extrusion from the cell (in particular via Na+/Ca2+ exchange) rather than from a persistent increase in Ca2+ permeability of neuronal membrane.
Khodorov
B
B
Institute of General Pathology and Pathophysiology, Russian Academy of Medical Sciences, Moscow.
Pinelis
V
V
Golovina
V
V
Fajuk
D
D
Andreeva
N
N
Uvarova
T
T
Khaspekov
L
L
Victorov
I
I
D000818:Animals; D017920:Antiporters / Q000378:metabolism; D002118:Calcium / Q000378:metabolism*; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology; D003600:Cytosol / Q000378:metabolism; D005971:Glutamates / Q000633:toxicity*; D006624:Hippocampus / Q000166:cytology; D066298:In Vitro Techniques; D009474:Neurons / Q000187:drug effects*; D051381:Rats; D017208:Rats, Wistar; D012964:Sodium / Q000502:physiology; D019831:Sodium-Calcium Exchanger
D017920:Antiporters; D005971:Glutamates; D019831:Sodium-Calcium Exchanger; D012964:Sodium; D002118:Calcium