| Autor: |
Alexey S, Averin, Ludmila A, Andreeva, Svetlana S, Popova, Leonid S, Kosarsky, Andrey I, Anufriev, Miroslav N, Nenov, Olga V, Nakipova |
| Rok vydání: |
2020 |
| Zdroj: |
Journal of comparative physiology. B, Biochemical, systemic, and environmental physiology. |
| ISSN: |
1432-136X |
| Popis: |
The effect of phenylephrine (PE) on right ventricle papillary muscle (PM) and aortic segment (AS) contractile activity was studied in long-tailed ground squirrels Urocitellus undulatus during summer activity, torpor and interbout active (IBA) periods in comparison to rat. We found that PE (10 μM) exerts positive inotropic effect on ground squirrel PM that was blocked by α1-AR inhibitor-prazosin. PE differently affected frequency dependence of PM contraction in ground squirrels and rats. PE significantly increased the force of PM contraction in summer and hibernating ground squirrels including both torpor and IBA predominantly at the range of low stimulation frequencies (0.003-0.1 Hz), while in rat PM it was evident only at high stimulation frequency range (0.2-1.0 Hz). Further, it was found that PE vasoconstrictor effect on AS contractility is significantly higher in ground squirrels of torpid state compared to IBA and summer periods. Overall vasoconstrictor effect of PE was significantly higher in AS of ground squirrels of all periods compared to rats. Positive inotropic effect of PE on PM along with its vasoconstrictor effect on AS of ground squirrels was not affected by pretreatment with inhibitors of L-type Ca |
| Databáze: |
OpenAIRE |
| Externí odkaz: |
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