Vasostatins exert negative inotropism in the working heart of the frog.
An in vitro isolated working frog heart (Rana esculenta) was used to study the effects of exogenous CGA(1-76) (vasostatin 1), CGA(1-113) (vasostatin 2), and the synthetic CGA(7-57) on cardiac performance. Under basal cardiac conditions, the dose-response curves of the three peptides from 10(-8) to 10(-7) M showed a significant calcium-dependent negative inotropism that involved neither the endocardial endothelium nor the adrenergic and muscarinic receptors. In addition, the CgA fragments clearly counteracted the typical positive inotropism of isoprenaline (10(-<9) M). Taken together, these results provide the first evidence for a cardio-suppressive role for the vasostatins.
Corti
A
A
Department of Pathology and Molecular Medicine, DIBIT-San Raffaele H Scientific Institute, 20132 Milan, Italy.
Mannarino
C
C
Mazza
R
R
Colombo
B
B
Longhi
R
R
Tota
B
B
D000818:Animals; D002118:Calcium / Q000378:metabolism; D002135:Calcium-Binding Proteins / Q000494:pharmacology*; D037282:Calreticulin; D004305:Dose-Response Relationship, Drug; D004699:Endocardium / Q000166:cytology; D005260:Female; D006321:Heart / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D010446:Peptide Fragments / Q000494:pharmacology*; D010455:Peptides / Q000737:chemistry; D010477:Perfusion; D011893:Rana esculenta; D012261:Ribonucleoproteins / Q000494:pharmacology*
D002135:Calcium-Binding Proteins; D037282:Calreticulin; D010446:Peptide Fragments; D010455:Peptides; D012261:Ribonucleoproteins; C121986:vasostatin; D007545:Isoproterenol; D002118:Calcium