β‐agonist‐induced inhibitory‐guanine‐nucleotide‐binding regulatory protein coupling to adenylate cyclase in mollusc Anodonta cygnea foot muscle sarcolemma

• Published in: European journal of biochemistry Vol. 210; no. 1; pp. 279 - 286
• Main Authors: PERTSEVA, Marianna N., KUZNETZOVA, Ludmila A., PLESNEVA, Svetlana A., GRISHIN, Alexander V., PANCHENKO, Mikhail P.
• Format: Journal Article
• Language: English
• Published: Oxford, UK Blackwell Publishing Ltd 15.11.1992
• Subjects: Adenylyl Cyclase Inhibitors; Adenylyl Cyclases - metabolism; Amino Acid Sequence; Animals; Anodonta cygnea; Binding Sites; Blotting, Western; coupling; Cyclic AMP - metabolism; Dihydroalprenolol - metabolism; Electrophoresis, Polyacrylamide Gel; enzymatic activity; GTP-Binding Proteins - metabolism; guanine nucleotide-binding protein; hormones; inhibition; isoproterenol; Isoproterenol - pharmacology; Marine; Molecular Sequence Data; Mollusca - enzymology; muscles; Muscles - enzymology; neurosecretory system; Receptors, Adrenergic, beta - drug effects; Receptors, Adrenergic, beta - metabolism; Sarcolemma - enzymology
• ISSN: 0014-2956; 1432-1033
• DOI: 10.1111/j.1432-1033.1992.tb17418.x

In the sarcolemma fraction of foot muscles of a fresh‐water bivalve mollusc, Anodonta cygnea, a direct inhibitory, rather than stimulatory, effect of the β‐adrenergic agonist isoproterenol, at micromolar concentration, on cAMP level and adenylate cyclase activity, was revealed. It was blocked by β‐ but not α‐adrenergic antagonists. A single class of [3H]dihydroalprenolol‐binding sites with binding properties of β‐adrenergic receptor was detected in mollusc sarcolemma. Potentiation of the inhibitory effect of isoproterenol on mollusc adenylate cyclase activity by GTP or guanosine 5′‐[β,γ‐imido]triphosphate at micromolar concentrations, and its elimination in the presence of guanosine 5′‐[β‐thio]diphosphate, were shown. The pertussis‐toxin‐induced ADP‐ribosylation of sarcolemma 40‐kDa protein [immunochemically related in the C‐terminal part to pertussis‐toxin‐sensitive guanine‐nucleotide‐binding regulatory protein (G‐protein) α subunits of vertebrates], as well as the treatment of mollusc sarcolemma with antisera responsive to the C‐terminus of vertebrate inhibitory G‐protein (Gi) α subunit led to elimination of the inhibitory effect of isoproterenol on adenylate cyclase activity. The results obtained suggest that β‐agonist‐induced inhibition of adenylate cyclase in A. cygnea foot muscle may be realized via the β‐adrenoreceptor/Gi signalling pathway.