Vn. Mutafovayambolieva et Dp. Westfall, ENDOTHELIN-3 CAN BOTH FACILITATE AND INHIBIT TRANSMITTER RELEASE IN THE GUINEA-PIG VAS-DEFERENS, European journal of pharmacology, 285(2), 1995, pp. 213-216
Endothelin-3 (10 nM) produced a significant facilitation of the releas
e of ATP from the in vitro guinea-pig vas deferens. This effect was co
nverted to an inhibition of release by pretreatment with BQ-123, cyclo
-(D-Trp,D-Asp,L-Pro,D-Val,L-Leu), an endothelin ET(A) receptor antagon
ist. Desensitization of endothelin ET(B) receptors by sarafotoxin S6c
antagonized, but did not reverse, the facilitatory effect of endotheli
n-3. The release of noradrenaline was not facilitated by endothelin-3;
however, following pretreatment with BQ-123 the release of noradrenal
ine was reduced by the peptide. These results indicate that there may
be both facilitatory and inhibitory prejunctional endothelin receptors
and further suggest that the release of the sympathetic nerve cotrans
mitters ATP and noradrenaline may be differentially modulated.