Structural-functional characteristics of the adenylyl cyclase signaling system regulated by biogenic amines and peptide hormones in muscles of the earthworm Lumbricus terrestris

• Published in: Journal of evolutionary biochemistry and physiology 2008-10, Vol.44 (5), p.552-561
• Main Authors: Shpakov, A. O, Shpakova, E. A, Kuznetsova, L. A, Plesneva, S. A, Pertseva, M. N
• Format: Article
• Language: English
• Subjects: Animal Physiology; Biochemistry; Biomedical and Life Sciences; Biophysics; Comparative and Ontogenic Biochemistry; Evolutionary Biology; Hormones; Life Sciences; Peptides; Proteins; Worms
• ISSN: 0022-0930; 1608-3202
• DOI: 10.1134/S0022093008050034

It has been shown for the first time that biogenic amines (catecholamines and tryptophane derivatives) stimulate dose-dependently activity of adenylyl cyclase (AC) and GTP-binding of G-proteins in muscle of the skin-muscle sac of the earthworm Lumbricus terrestris. By efficiency of their stimulating action on the AC activity, biogenic amines can be arranged in the following sequence: octopamine > tyramine > tryptamine [almost equal to] serotonin > dopamine > isoproterenol [almost equal to] adrenalin. The sequence of efficiency of their action on GTP-binding is somewhat different: serotonin > tryptamine > octopamine > dopamine [almost equal to] tyramine > adrenaline > isoproterenol. Sensitivity of AC and G-proteins in the worm muscle to biogenic amines is similar with that in smooth muscle of the mollusc Anodonta cygnea (invertebrates), but differs markedly by this parameter from the rat myocardium (vertebrates). It has also been revealed that AC in the worm muscle is regulated by peptide hormones, relaxin and somatostatin, whose action is comparable with that in the mollusc muscle, but much weaker that the action of these hormones on the rat myocardium AC activity. Use of Cterminal peptides of α-subunits of G-proteins of the stimulatory (385-394 Gαs) and inhibitory (346-355 Gαi2) types that disrupt selectively the hormonal signal transduction realized via Gsand Giproteins, respectively, allowed establishing that the AC-stimulating effects of relaxin, octopamine, tyramine, and dopamine in the worm muscle are realized via the receptors coupled functionally with Gs-protein; the AC-inhibiting effect of somatostatin is realized via the receptor coupled with Gi-protein, whereas serotonin and tryptamine activate both types of G-proteins.