the action of e and ne on the alpha 1 and es alpha 2 receptors initiates the compensatory vasoconstriction , whereas action of these catecholamines on the ps alpha 2 located on the presynaptic membrane inhibits further release of ne from peripheral nerve terminals , thereby reducing the effect of the innervated alpha 1 receptors .
C0007412
catecholamines
C0028351
ne