Arteriolar and venular constriction; Iris dilatation; Intestinal relaxation;
Intestinal sphincter contraction; Pilomotor contraction; Bladder sphincter contraction; Contraction of the pregnant uterus; Ejaculation of seminal fluid. Beta: The beta receptor is a G-protein-coupled seven transmembrane span polypeptide.
Beta receptor numbers in tissues may decrease with chronic stimulation leading to desensitisation (down-regulation) or increase with chronic blockade (up-regulation). Beta 1
Cardioacceleration: chronotropic effect
Increased myocardial contractility: positive inotropic effect
The cardiac positive inotropic effects result from increased calcium concentration due to phosphorylation of L-type calcium channels and phosphorylation of sarcolemmal calcium pumps. Beta 2 Vasodilatation Intestinal relaxation Uterine relaxation Bronchodilatation Calorigenesis Bladder wall relaxation
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