Gender difference in levels of alpha2-adrenoceptor mRNA in the rat tail artery

To investigate the hypothesis that differing mRNA levels underlie gender differences in the contractile response of the rat tail artery, alpha2-adrenoceptor mRNA was measured using in situ hybridization. Messenger RNA for the alpha2A- and alpha2C-adrenoceptor subtypes was found localized to the smooth muscle layer. There was no detectable mRNA present for the alpha2B-adrenoceptor subtype. Levels of alpha2C-adrenoceptor mRNA were greater in female compared to male tail arteries (417 +/- 35 vs. 263 +/- 38 dpm/mg, P = 0.01), while levels of alpha2A-adrenoceptor mRNA were the same in both sexes. Levels of alpha2-adrenoceptor mRNA may parallel levels of functioning protein present in the rat tail artery.