Distribution of adrenoceptor subtypes type tissue action Most vascular smooth muscle Contraction pupillary dilator muscle Contraction(dilates pupil) al Pilomotor smooth muscle Erects hair Prostate contraction heart Increase force of contraction Postsynaptic CNS adrenoceptors Probably multiple platelet aggregation a2 Adrenergic and cholinergic nerve terminal Inhibition of transmitter release Some vascular smooth muscle contraction Fat cells Inhibition of lipolysis B1 heart Increase force and rate of contraction Respiratory,uterine and vascular smooth muscle Promote smooth muscle relaxation B2 Skeletal muscle Promote potassium uptake Human liver Activates glycogenolysis B3 Fat cells Activates lipolysis D1 Smooth muscle Dilates renal blood vessels D2 Nerve endings Modulates transmitter releasetype tissue action α1 Most vascular smooth muscle Contraction pupillary dilator muscle Contraction (dilates pupil) Pilomotor smooth muscle Erects hair Prostate contraction heart Increase force of contraction α2 Postsynaptic CNS adrenoceptors Probably multiple platelet aggregation Adrenergic and cholinergic nerve terminal Inhibition of transmitter release Some vascular smooth muscle contraction Fat cells Inhibition of lipolysis β1 heart Increase force and rate of contraction β2 Respiratory, uterine and vascular smooth muscle Promote smooth muscle relaxation Skeletal muscle Promote potassium uptake Human liver Activates glycogenolysis β3 Fat cells Activates lipolysis D1 Smooth muscle Dilates renal blood vessels D2 Nerve endings Modulates transmitter release Distribution of adrenoceptor subtypes