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Effect of Chronic Ethanol Treatment on Ca 2+ ‐Inhibited Adenylyl Cyclase in Mouse Striatum
Author(s) -
Ikeda Hiroshi,
Hatta Shinichi,
Ozawa Hiroki,
Ohshika Hideyo,
Saito Toshikazu
Publication year - 1999
Publication title -
alcoholism: clinical and experimental research
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.267
H-Index - 153
eISSN - 1530-0277
pISSN - 0145-6008
DOI - 10.1111/j.1530-0277.1999.tb04524.x
Subject(s) - adenylyl cyclase , forskolin , endocrinology , medicine , striatum , ethanol , g protein , chemistry , biology , receptor , stimulation , biochemistry , dopamine
In the present study, to investigate the possibility that chronic ethanol treatment might alter Ca 2+ ‐inhibited type 5 adenylyl cyclase (AC) activity, we examined the effect of chronic ethanol treatment on striatal dopaminergic signal transduction, especially the AC system, in mice. We fed male C57BL/6 mice for 7 days with a 5% ethanol‐containing or control liquid diet. Basal and forskolin‐stimulated AC activities were reduced in striatal membranes of ethanol‐treated mice. 5′‐guanylylimidodiphosphate‐stimulated AC activity was also decreased in ethanol‐treated mice. But no significant differences were observed in the levels of the guanine nucleotide binding protein subunits Gsα and Gi 1&2α determined by immunoblotting, between ethanol‐treated and control mice. These results indicated that the function of the catalytic subunit of AC was decreased in the straitum of chronically ethanol‐treated mice. We further examined the inhibitory regulation of AC activity in the context of a change of type 5 AC. Inhibition of forskolin‐stimulated AC activity by 10 μM free Ca 2+ was smaller in ethanol‐treated mice than in control mice. However, the protein level of type 5 AC in the striatum, determined by immunoblotting, was not significantly different between ethanol‐treated and control mice. These findings suggest that Ca 2+ ‐inhibited, presumably type 5, AC activity is reduced in mouse striatum by chronic ethanol treatment, and that this reduction is not due to a decrease in type 5 AC expression.