Receptors of Biogenic Amines in Muscle Membranes of Molluscs

In a number of molluscs belonging to different groups, serotonin and β-adrenergic agonists have a stimulatory effect on the sarcolemmal adenylyl cyclase (AC) activity, which is potentiated by guanine nucleotides. Catecholamines (isoprotenerol > adrenaline > noradrenaline) inhibit AC activity in Anodonta cygnea sarcolemma. In muscle membranes of Anodonta, Mizuhopecten and Spisula, a serotonin receptor (5-HTR) and a β-adrenoreceptor (β-AR) were identified. Guanine nucleotides lowered the affinities of 5-HTR and β-AR to agonists.