text: << Carvedilol >> produced significant inhibition of the [[ alpha 1 adrenoceptor ]] mediated pressor response to cirazoline in the pithed rat, but had no effect on the alpha 2 adrenoceptor mediated pressor response to B-HT 933, suggesting that carvedilol is also an alpha 1 adrenoceptor antagonist at antihypertensive doses.