Evidence for an inhibitory effect of nitric oxides on neuropeptide secretion from isolated neural lobe of the rat pituitary gland.
The present study aims at investigating the effect of pharmacological manipulation of nitric oxides (NOs) formation in the rat neurohypophysis on the secretion of vasopressin (AVP). We found that the NO synthase antagonist L-NAME and free-ferrous hemoglobin (an NO inactivator) produced a transient and significant enhancement of basal secretion of AVP from incubated glands. Conversely, the NO precursor L-arginine (but not its inactive counterpart D-arginine) antagonized the stimulatory influence of L-NAME on both AVP and oxytocin (OT) output. Elevation of NOs formation triggered by means of the NO donor SIN-1 likewise dampened spontaneous, as well as stimulated, AVP release. It is concluded that NOs molecules show up as potent regulators of neuropeptide secretion at the level of nerve terminals in the neurohypophysis.
Lutz-Bucher
B
B
Institut de Physiologie, CNRS URA 1446, Université Louis Pasteur, Strasbourg, France.
Koch
B
B
D000594:Amino Acid Oxidoreductases / Q000037:antagonists & inhibitors; D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000037:antagonists & inhibitors / Q000494:pharmacology; D001127:Arginine Vasopressin / Q000378:metabolism; D006454:Hemoglobins / Q000494:pharmacology; D066298:In Vitro Techniques; D008297:Male; D008981:Molsidomine / Q000031:analogs & derivatives / Q000494:pharmacology; D019331:NG-Nitroarginine Methyl Ester; D009479:Neuropeptides / Q000378:metabolism*; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000494:pharmacology*; D019001:Nitric Oxide Synthase; D010121:Oxytocin / Q000378:metabolism; D010904:Pituitary Gland, Posterior / Q000187:drug effects / Q000378:metabolism*; D051381:Rats; D017208:Rats, Wistar
D006454:Hemoglobins; D009479:Neuropeptides; D001127:Arginine Vasopressin; D009569:Nitric Oxide; D010121:Oxytocin; C002385:linsidomine; D001120:Arginine; D008981:Molsidomine; D019001:Nitric Oxide Synthase; D000594:Amino Acid Oxidoreductases; D019331:NG-Nitroarginine Methyl Ester