The present work has analyzed the consequences of chronic intermittent high-altitude hypoxia for functioning of the G protein-mediated adenylyl cyclase (AC) signaling system in the right (RV) and left ventricular (LV) myocardium in rats. Adaptation to hypoxia did not appreciably affect the number of beta-adrenoceptors and the content of predominantly membrane-bound alpha-subunit (G(s)alpha) of the stimulatory G protein, but it raised the amount of cytosolic G(s)alpha in RV. The levels of myocardial inhibitory Galpha protein were not altered. Activity of AC stimulated by GTP, fluoride, forskolin, or isoprotertenol was reduced by approximately 50% in RV from chronically hypoxic rats, and a weaker depression was also found in LV. In addition, hypoxia significantly diminished a functional activity of membrane-bound G(s)alpha in both RV and LV. The RV baseline contractile function was markedly increased in chronically hypoxic animals, and its sensitivity to beta-adrenergic stimulation was decreased. Animals recovering from hypoxia for 5 wk still exhibited markedly elevated levels of cytosolic G(s)alpha and significantly lower activity of AC in RV than did age-matched controls, but contractile responsiveness to beta-agonists was normal.
- MeSH
- adenylátcyklasy metabolismus MeSH
- atmosférický tlak MeSH
- beta-adrenergní receptory metabolismus MeSH
- chronická nemoc MeSH
- funkce pravé komory srdeční MeSH
- hypoxie metabolismus patologie MeSH
- isoprenalin farmakologie MeSH
- kardiotonika farmakologie MeSH
- kontrakce myokardu MeSH
- krysa rodu Rattus MeSH
- myokard metabolismus patologie MeSH
- potkani Wistar MeSH
- protein - isoformy metabolismus MeSH
- proteiny vázající GTP - alfa-podjednotky Gs metabolismus MeSH
- signální transdukce * MeSH
- tělesná hmotnost MeSH
- velikost orgánu MeSH
- zvířata MeSH
- Check Tag
- krysa rodu Rattus MeSH
- mužské pohlaví MeSH
- zvířata MeSH
- Publikační typ
- časopisecké články MeSH
- práce podpořená grantem MeSH
- Názvy látek
- adenylátcyklasy MeSH
- beta-adrenergní receptory MeSH
- isoprenalin MeSH
- kardiotonika MeSH
- protein - isoformy MeSH
- proteiny vázající GTP - alfa-podjednotky Gs MeSH
