Classification of beta-adrenoceptors in the microcirculation of skeletal muscle.

Nervous and humoral beta-adrenergic, postjunctional effects on microvascular resistance, on precapillary sphincter tone, and on transcapillary fluid exchange in cat skeletal muscle (Lundvall & Järhult 1974, 1976 a, Lundvall & Hillman 1978 a, b) were evaluated with regard to the beta 1- or beta 2-specificity of the adrenoceptors. Marked beta 2-dilator responses but no significant beta 1-effects were observed. The conclusion was therefore reached that neurogenic as well as humoral beta-adrenergic control of the microcirculation in skeletal muscle is exerted via activation of beta 2-adrenoceptors.