Fura-2 measurement of cytosolic free calcium in rat brain cortical synaptosomes and the influence of ethanol.
The effects of ethanol on resting and KCl-depolarized cytosolic calcium concentrations ([Ca2+]i) were measured in purified rat cortical synaptosomes using the calcium indicator fura-2. Ethanol (500-700 mM) significantly elevated the resting [Ca2+]i by 13-25% in the presence of 100 microM external calcium. In the absence of external Ca2+, ethanol (50-200 mM) significantly increased [Ca2+]i by 17-23%. Ethanol (200-700 mM) also significantly decreased KCl-induced rise in [Ca2+]i (delta K) by 40-82% in fura-2 loaded preparations incubated in the absence or presence of external calcium. Ethanol did not produce a significant change in delta K at 50 and 100 mM concentrations. These results suggest that ethanol may cause an elevation in [Ca2+]i via mobilization of intracellular calcium stores which may be linked to a calcium-dependent inactivation of voltage-sensitive calcium channels.
Rezazadeh
S M
SM
Division of Pharmacology, College of Pharmacy, University of Texas, Austin 78712.
Woodward
J J
JJ
Leslie
S W
SW
D000818:Animals; D001572:Benzofurans; D002118:Calcium / Q000378:metabolism*; D002540:Cerebral Cortex / Q000378:metabolism* / Q000648:ultrastructure; D003600:Cytosol / Q000378:metabolism*; D004563:Electrochemistry; D000431:Ethanol / Q000494:pharmacology*; D005456:Fluorescent Dyes; D016257:Fura-2 / Q000031:analogs & derivatives*; D009994:Osmolar Concentration; D051381:Rats; D012146:Rest; D013574:Synaptosomes / Q000378:metabolism*
D001572:Benzofurans; D005456:Fluorescent Dyes; C049925:fura-2-am; D000431:Ethanol; D002118:Calcium; D016257:Fura-2