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5-Hydroxytryptamine increases contractile force in porcine right atrium but not in left ventricle.
- Source :
-
Naunyn-Schmiedeberg's archives of pharmacology [Naunyn Schmiedebergs Arch Pharmacol] 1992 Nov; Vol. 346 (5), pp. 486-9. - Publication Year :
- 1992
-
Abstract
- Positive chronotropic as well as inotropic effects of 5-hydroxytryptamine (5-HT) have been observed in pig atrial tissue, but no data are available about the direct effects of 5-HT on ventricular tissue. In the present study we investigated inotropic effects of 5-HT on atrial and ventricular trabeculae obtained from hearts of 3 months old pigs. The baseline isometric contractile force was significantly higher in ventricular (4.14 +/- 1.25 mN) than in atrial tissue (0.47 +/- 0.11 mN). A noradrenaline concentration-response curve (0.01 to 10 mumol/l) was used to check contractile responsiveness of the tissue and all responses were expressed as percentage of the response to 10 mumol/l noradrenaline. Noradrenaline caused a concentration-dependent increase in contractile force in both atrial and ventricular trabeculae. In contrast, though 5-HT (0.01 to 100 mumol/l) did increase force of contraction in atrial tissue (maximum: 72 +/- 20% of the response to noradrenaline 10 mumol/l), the contractility of ventricular trabeculae was not significantly affected (maximum: 12 +/- 6%). The present data show that, in contrast to atrial tissue, contractile force of ventricular tissue could not be significantly affected by 5-HT. To our knowledge, this is the first study to show that an agent which increased force of contraction in the atrium, did not have a corresponding effect on the ventricle. These findings may have important implications for a better understanding of the physiology and pharmacology of cardiac contractility.
Details
- Language :
- English
- ISSN :
- 0028-1298
- Volume :
- 346
- Issue :
- 5
- Database :
- MEDLINE
- Journal :
- Naunyn-Schmiedeberg's archives of pharmacology
- Publication Type :
- Academic Journal
- Accession number :
- 1470219
- Full Text :
- https://doi.org/10.1007/BF00169001