MODULATION OF [H-3] NORADRENALINE RELEASE BY ENDOTHELIN-1 IN THE RAT TAIL ARTERY

The effect of endothelin-1 (ET-1) on the increase in perfusion pressure and the release of noradrenaline produced by electrical field stimulation were examined in isolated perfused/superfused rat tail arteries. ET-1 (1-30 nM) increased, in an identical concentration-dependent manner, the basal perfusion pressure and the stimulation-evoked tritum overflow, whereas the basal outflow of noradrenaline was not changed by the peptide. These results show that, besides its postjunctional vasoconstrictor effect, ET-1 exerts in the rat tail artery a prejunctional action which might be involved in the modulation of stimulation-evoked noradrenaline release from postganglionic nerves.