Co-release of neuropeptide Y (NPY) and noradrenaline from the sympathetic nerve terminals supplying the rat vas deferens; influence of calcium and the stimulation intensity.
Epididymal (E) and prostatic (P) segments of the rat vas deferens were incubated with tritium-labeled noradrenaline (NA); upon transmural electrical stimulation for 20 or 60 s (70 V, 1 ms, 3-35 Hz), the outflow of immunoreactive neuropeptide Y (ir-NPY) and NA was detected in the superfusion media. Ir-NPY was detected only following trains of 35 Hz for 60 s in both E and P. In contrast, tritium was released in a graded fashion following trains of 3, 15 or 35 Hz stimulation for 60 s in E, whereas in P it reached a plateau at frequencies larger than 15 Hz. The outflow of tritium, under present conditions, was dependent on the duration of the stimuli, while the release of ir-NPY was only evoked with stimuli of 60 s duration. In the absence of external Ca2+, neurotransmission was blocked and co-release of ir-NPY and NA was prevented.
Torres
G
G
Department of Physiology, Faculty of Biological Sciences, P. Catholic University of Chile, Santiago.
Bitran
M
M
Huidobro-Toro
J P
JP
D000818:Animals; D002118:Calcium / Q000494:pharmacology; D004533:Egtazic Acid / Q000494:pharmacology; D004558:Electric Stimulation; D004822:Epididymis; D066298:In Vitro Techniques; D007700:Kinetics; D008297:Male; D009412:Nerve Fibers / Q000187:drug effects / Q000502:physiology*; D009478:Neuropeptide Y / Q000378:metabolism*; D009638:Norepinephrine / Q000378:metabolism*; D011467:Prostate; D051381:Rats; D017207:Rats, Sprague-Dawley; D013564:Sympathetic Nervous System / Q000187:drug effects / Q000502:physiology*; D013997:Time Factors; D014316:Tritium; D014649:Vas Deferens / Q000294:innervation*
D009478:Neuropeptide Y; D014316:Tritium; D004533:Egtazic Acid; D002118:Calcium; D009638:Norepinephrine