THE INOTROPIC INFLUENCE OF ANGIOTENSIN II ON THE WORKING HEART OF THE EEL (Anguilla anguilla): PARACRINE ASPECTS AND SUBCELLULAR MECHANISMS
Angiotensin II (Ang II) not only is a pluripotential hormone but is also an autocrine-paracrine cardiac factor modulating short- (i.e. inotropism) and long-term (i.e. hypertrophy) adaptations of the heart. While a wide range of species-dependent variations is apparent in the inotropic effects of Ang...
| Main Authors: | , , , |
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.629.9203 http://www-heb.pac.dfo-mpo.gc.ca/congress/2002/Cardiovasc/Imbrogno.pdf |
| Summary: | Angiotensin II (Ang II) not only is a pluripotential hormone but is also an autocrine-paracrine cardiac factor modulating short- (i.e. inotropism) and long-term (i.e. hypertrophy) adaptations of the heart. While a wide range of species-dependent variations is apparent in the inotropic effects of Ang II in mammalian myocardia, there is a lack of information regarding the direct influence of this hormone on the mechanical performance of the fish heart. Therefore, experiments were carried out in fresh water eels (Anguilla anguilla) using an isolated working heart preparation, previously set up in our lab (Imbrogno et al., 2001), to explore whether Ang II exerted direct inotropic effects and to clarify the underlying mechanisms. Ang II (10 –11 ÷ 10-7 M) elicited negative chronotropic influence and caused on the electrically paced preparations a cardio-suppressive action, decreasing stroke volume (SV) and 56 stroke work (SW). This negative inotropic effect was abrogated by a selective AT1 subtype antagonist, CV 11974 (10-7 M), specific for non mammalian |
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