Sympathetic nerve-mediated release of ATP from the guinea-pig vas deferens is unaffected by reserpine.
The release of ATP from the guinea-pig vas deferens was measured using the luciferin-luciferase assay. The effects of reserpine, tetrodotoxin, 6-hydroxydopamine and guanethidine on this efflux were investigated. Reserpine, which produced extensive loss of noradrenaline (NA) (about 99%) and eliminated the second phase of the nerve-mediated contraction, failed to impair either ATP release from the vas deferens or the concomitant 'twitch' contraction; in fact both were increased. Therefore the neurotransmitter mediating the twitch cannot be NA, thus excluding the gamma-receptor hypothesis. Furthermore, since the release of ATP is unaffected by reserpine, it is unlikely that ATP is being released from smooth muscle as a consequence of the post-junctional actions of NA. Tetrodotoxin, 6-hydroxydopamine and guanethidine substantially reduced or abolished the release of ATP and both phases of the nerve-mediated response. To conclude, in the guinea-pig vas deferens, ATP co-released with NA from sympathetic nerves, mediates the twitch phase of the contraction and its underlying electrical events.
D000255:Adenosine Triphosphate / Q000378:metabolism*; D000818:Animals; D006145:Guanethidine / Q000494:pharmacology; D006168:Guinea Pigs; D006892:Hydroxydopamines / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D009130:Muscle, Smooth / Q000187:drug effects / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism; D016627:Oxidopamine; D011224:Prazosin / Q000494:pharmacology; D012110:Reserpine / Q000494:pharmacology*; D013563:Sympathectomy, Chemical; D013564:Sympathetic Nervous System / Q000502:physiology*; D013779:Tetrodotoxin / Q000494:pharmacology; D014649:Vas Deferens / Q000187:drug effects / Q000378:metabolism
D006892:Hydroxydopamines; D013779:Tetrodotoxin; D012110:Reserpine; D016627:Oxidopamine; D000255:Adenosine Triphosphate; D009638:Norepinephrine; D011224:Prazosin; D006145:Guanethidine