Effect ofα,β-methylene ATP on the potentiation of contractions to field stimulation of rat vas deferens by eledoisin

Eledoisin potentiated contractions to field stimulation of rat vas deferens. This effect was antagonized by [D-Pro2, D-Trp7,9]-substance P (0.01 mmol/L), a tachykinin receptor antagonist but not by prazosin (lμmol/L), anα1-adrenoceptor antagonist. Desensitization of P2-purinoceptors in rat vas deferens by α,β- methylene ATP (0.03 mmol/L, 2 min) attenuated the contractile response of the tissue to field stimulation and markedly reduced the potentiating effect of eledoisin. α,β-methylene ATP (0.002-0.2 mmol/L) had no significant effect on 125I-Bolton Hunter reagent conjugate of eledoisin (125I-BHE) binding to NK2 tachykinin receptors in the rat vas deferens. It is concluded that the potentiating effect of eledoisin on the contractions to field stimulation in the rat vas deferens may be the result of an enhancement of purinergic rather than adrenergic neurotransmission.