DIFFERENCES IN ALPHA(2)-ADRENOCEPTOR MODULATION OF CALCIUM CHANNELS IN VASCULAR SMOOTH-MUSCLE CELLS OF MALE AND FEMALE RATS

Effects of the alpha(2)-adrenergic agonist clonidine on current throug h Ca2+ channels was recorded from vascular smooth muscle cells isolate d from tail arteries and aortae of male and female rats. The average B a2+ current in control was not significantly different between males a nd females; however, clonidine (1 mu M) enhanced Ba2+ current through Ca2+ channels in cells from females, but not from males. The greater s ensitivity of vascular smooth muscle cells to clonidine may underlie d ifferent contractile responses to alpha(2)-adrenergic agonists between males and females.