Title: Effects of the alpha 1-adrenoceptor agonist phenylephrine in pig heart. Study of the direct action on contractile proteins.
Abstract:The effects of the alpha 1-adrenoceptor agonist phenylephrine (CAS 59-42-7) on Ca++ sensitivity of the contractile proteins and on force of contraction of the heart were studied in right ventricular p...The effects of the alpha 1-adrenoceptor agonist phenylephrine (CAS 59-42-7) on Ca++ sensitivity of the contractile proteins and on force of contraction of the heart were studied in right ventricular preparations isolated from pigs. In contracting trabeculae phenylephrine (3-100 mumol/l) increased force of contraction in the presence of propranolol maximally by 91.8 +/- 36.2% (n = 5). The effect of phenylephrine was antagonized by prazosin, indicating an alpha-adrenoceptor-mediated positive inotropic effect. Glycerol- and Lubrol WX-extracted trabeculae ("chemically skinned") were activated by Ca(++)-concentrations between 0.01 and 47.7 mumol/l. Phenylephrine (0.1-100 mumol/l) did not affect the Ca++ activated force in these preparations. A direct intracellular action of phenylephrine on contractile proteins is thus rather unlikely to contribute to the positive inotropic effect of phenylephrine.Read More
Publication Year: 1993
Publication Date: 1993-04-01
Language: en
Type: article
Indexed In: ['pubmed']
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