Katsura M, Shibasaki M, Hayashida S, Torigoe F, Tsujimura A, Ohkuma S. Increase in Expression of α1 and α2/δ1 Subunits of L-Type High Voltage-Gated Calcium Channels After Sustained Ethanol Exposure in Cerebral Cortical Neurons.
J Pharmacol Sci 2006;
102:221-30. [PMID:
17031067 DOI:
10.1254/jphs.fp0060781]
[Citation(s) in RCA: 16] [Impact Index Per Article: 0.9] [Reference Citation Analysis] [Abstract] [MESH Headings] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 10/24/2022] Open
Abstract
Previous reports revealed up-regulation of L-type high voltage-gated calcium channels (HVCCs) in mouse brains with ethanol physical dependence. We investigated mechanisms of enhancement of L-type HVCC function using mouse cerebrocortical neurons exposed to 50 mM ethanol for 3 days and the brains of mouse physically dependent on ethanol. Ethanol facilitated 30 mM KCl-stimulated (45)Ca(2+) influx in dose- and duration-dependent manners, which was abolished by nifedipine, an inhibitor specific to L-type HVCCs, but not by inhibitors for other types of HVCCs. Increase in [(3)H]PN200-110 binding to the particulate fractions from the ethanol-treated neurons was due to increased B(max) value with no changes in K(d) value. Western blot analysis showed the increased expression of alpha1C, alpha1D, and alpha2/delta1 subunits with decreased beta4 subunit expression and no changes in expressions of alpha1A, alpha1B, alpha1F, and alpha2 subunits. A similar pattern of the changes in the expression of these subunits of L-type HVCCs were observed in the cerebral cortex from mouse with ethanol physical dependence. These results indicate that sustained ethanol exposure to the neurons induces up-regulation of L-type HVCCs, which is due to increased expressions of alpha1C, alpha1D, and alpha2/delta1 subunits, and produces no alterations in P/Q- and N-type HVCC functions.
Collapse