[Activation of cardiac contractivity of the edible snail H. pomatia under effect of thrombin. Study of role of cAMP].
Thrombin acts on mammalian cells through specific, the so-called protease-activated receptors (PARs). The thrombin action is mediated via three out of four known types of these receptors PAR(1, 3, 4). Mammalian thrombin receptors, apart from performance of other functions, control cardiac and vascular contractility. It is not known whether receptors of such kind exist in invertebrate animals. In the present work we have showed for the first time that thrombin in the concentration range of 0.01-1 units/ml increases amplitude of contractions of the isolated heart ventricle of the edible snail Helix pomatia. Its effect is reproduced by peptide ligands of receptors PAR1 and PAR4 that have sequences Ser-Phe-Leu-Leu-Arg-Asn (SFLLRN) and Glu-Tyr-Pro-Gly-Lys-Phe (QYPGKF), respectively. A potent activati of cardiac contractivity of H. pomatia is serotonin. A comparative study of mechanisms of action of serotonin and thrombin on the edible snail heart was carried out. cAMP participates in transduction of signal from serotonin receptors. On the membrane preparation from the H. pomatia heart, it was shown that thrombin and peptide ligands PAR(1, 4), unlike serotonin, did not increase adenylyl cyclase activity. Thus, mechanism of activation of cardiac contractivity of H. pomatia by thrombin differs from the action mechanism of serotonin. It is suggested that molluscs have receptors homologous to protease activated mammalian receptors.
Solomonova
V G
VG
Avdonin
P P
PP
Vinichenko
E S
ES
Sukhanova
I F
IF
Avdonin
P V
PV
D000818:Animals; D006339:Heart Rate / Q000187:drug effects / Q000502:physiology; D006372:Helix, Snails / Q000502:physiology*; D006490:Hemostatics / Q000494:pharmacology; D009200:Myocardial Contraction / Q000187:drug effects / Q000502:physiology; D013917:Thrombin / Q000494:pharmacology
D006490:Hemostatics; D013917:Thrombin