抄録
Androgen receptor (AR) activation by testosterone regulates the expression of many kinds of proteins and, thereby, castration, which significantly decreases serum testosterone level, prevents the maturation of mail organs. We previously reported that the functional expression of large conductance Ca2+-activated K+ (BK) channels is markedly diminished in smooth muscle from reproductive organ of castrated-rat (CAST). The decrease in BK channel expression was limited in organs, where ARs are extensively expressed. BK channels are ubiquitously expressed and possess obligatory roles in the regulation of membrane excitability in many types of cells including CNS neurons. We examine the possibility that BK channel expression in some regions of brain may possibly regulated by plasma testosterone level. Firstly, BK channel mRNA expression was examined in four regions of brain; amygdala hypothalamus, pituitary, hippocampus. Amygdala region, in which substantial expression of AR has been reported, had relative abundant expression of BK channel mRNA. Secondly, we investigated changes in BK channels expression in amygdale region in sham-operated -rats and CAST. Western blot analyses also demonstrated marked decrease in the amount of BKα protein in amygdala from CAST. The measurement of BK channel currents in isolated neurons from amygdala region was also performed by patch-clamp techniques. Taken together, the regulation of BK channel function in amygdala by testosterone and by gender difference can be suggested. [J Physiol Sci. 2008;58 Suppl:S76]
