| Autor: |
Orallo, Francisco, Verde, Ignacio, Loza, Ma Isabel, Alzueta, Alejandro F, Campos, Manuel, Freire-Garabal, Manuel |
| Zdroj: |
Journal of Pharmacy and Pharmacology; April 1992, Vol. 44 Issue: 4 p344-348, 5p |
| Abstrakt: |
In order to clarify the mechanism of hypotensive activity of platelet activating factor (PAF), the effects of this drug on blood pressure in anaesthetized normotensive rats, on KCl- and noradrenaline-induced 45Ca uptake and contractile responses in rat aorta rings with and without endothelium were studied. PAF (3 μg kg−1, i.v.) showed long-lasting hypotensive effects in anaesthetized normotensive rats accompanied by a significant increase in heart rate. PAF (0·1–10 μm) did not relax the contractions induced by noradrenaline (10 μm) or K+(60 Mm) in rubbed or intact rat aorta. PAF did not affect the basal uptake of 45Ca2+nor that induced by the two vasoconstrictor agents. In experiments in a calcium free medium, PAF (10 μm) had no effect on the noradrenaline- (10 μm) induced contractions. These results suggest that the hypotensive activity of PAF in normotensive anaesthetized rats is not due to a direct effect on rubbed and intact rat aorta rings (acting within the cell or blocking Ca2+influx through l-type transmembrane calcium channels). |
| Databáze: |
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