MITOCHONDRIAL ATP-SENSITIVE K+ CHANNELS (KATP) INFLUENCE FORCE DEVELOPMENT AND ANOXIC CONTRACTILITY IN A FLATFISH, YELLOWTAIL FLOUNDER (Limanda ferruginea), BUT NOT ATLANTIC COD (Gadus morhua) HEART.
Flatfishes often inhabit hypoxic waters and are known to exhibit substantial tolerance to cardiac acidosis and hypoxia. Studies on flounder suggest that flatfish have an atypical cardiovascular response to hypoxia. Winter flounder subjected to hypoxia exhibit increased cardiac output with no bradyca...
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| Format: | Text |
| Language: | English |
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| Online Access: | http://citeseerx.ist.psu.edu/viewdoc/summary?doi=10.1.1.535.394 http://www-heb.pac.dfo-mpo.gc.ca/congress/2002/Cardiovasc/MacCormack2.pdf |
| Summary: | Flatfishes often inhabit hypoxic waters and are known to exhibit substantial tolerance to cardiac acidosis and hypoxia. Studies on flounder suggest that flatfish have an atypical cardiovascular response to hypoxia. Winter flounder subjected to hypoxia exhibit increased cardiac output with no bradycardia (Cech et al., 1977). In isolated ventricular muscle from the European flounder, cardiac force development is initially potentiated following exposure to acidosis, before slowly declining over time (Gesser and Poupa, 1979). Gesser and Poupa have proposed that intracellular acidosis may trigger a release of stored mitochondrial Ca2+, subsequently enhancing force production. Adenosine 5’-triphosphate sensitive potassium (KATP) channels have been identified in goldfish hearts (Ganim et al., 1998). KATP channels are activated by a decline in energy status and are most likely to affect cardiac function throughout periods of impaired ATP production, such as hypoxia. In mammalian heart KATP channels exist on the sarcolemmal membrane (sKATP) and inner 91 |
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