Vn. Mutafovayambolieva et Rg. Radomirov, MODULATORY EFFECTS OF ENDOTHELIN-1 ON PURINERGIC AND ADRENERGIC COMPONENTS OF SYMPATHETICALLY-MEDIATED CONTRACTILE ACTIVITY OF RABBIT SAPHENOUS ARTERY, British Journal of Pharmacology, 112(4), 1994, pp. 1109-1117
1 The present study has been performed to evaluate the modulatory effe
cts of endothelin-1 (ET-1) on the purinergic and adrenergic components
of sympathetically-mediated contractile responses of endothelium-free
rabbit saphenous artery preparations. 2 ET-1 increased the smooth mus
cle tone, the pot value being 7.77 +/- 0.05. 3 Postjunctionally, ET-1
enhanced the responses to exogenous adenosine 5'-triphosphate (ATP) an
d did not influence those to exogenous noradrenaline (NA). 4 ET-1 incr
eased the contractile responses to short-lasting and to long-lasting e
lectrical held stimulation at a frequency of 5 or 10 Hz, showing a ten
dency towards decreasing the prazosin-sensitive component and increasi
ng the mATP-sensitive component of the contractile responses. 5 In pra
zosin-treated preparations ET-1 increased the residual mATP-sensitive
responses and this effect was more pronounced after yohimbine. 6 In mA
TP-treated preparations ET-1 increased the residual electrically-induc
ed contractions and this increase was abolished after yohimbine. 7 It
is suggested that ET-1 modulates co-transmission in the rabbit sapheno
us artery by potentiating postjunctionally the purinergic component of
the contractile responses to both exogenous ATP or electrical stimula
tion.