Effects of nociceptin and endomorphin 1 on the electrically stimulated human vas deferens.
OBJECTIVE
To examine the effects of nociceptin (NC) and endomorphin 1 (EM1) on electrical field stimulation (EFS)-induced contractions of the human vas deferens (hVD).


METHODS
Concentration-response curves to NC and EM1 were constructed in the absence and in presence of peptidase inhibitors (PI). In some experiments a NC receptor antagonist, [Phe1psi(CH2-NH)Gly2]NC(1-13)NH2 [F/G], 10 microM) or naloxone (1 microM) were included.


RESULTS
All data are mean(95%CI). In the presence of PI, NC inhibited twitches (Emax = 67(44,90)%; pEC50 = 7.28(6.95,7.61)). NC inhibition was sensitive to [F/G]. EM1 also inhibited twitches both in the absence (Emax = 82(73,91)% pEC50 = 7.07(6.92,7.22)) and presence (Emax = 83(76,90)%; pEC50 = 7.00(6.91, 7.09)) of PI. EM1 inhibition was sensitive to naloxone.


CONCLUSIONS
These data suggest that hVD express NC and opioid receptors that inhibit neurogenic contractions.
Bigoni
R
R
Department of Experimental and Clinical Medicine, Section of Pharmacology, University of Ferrara, Italy.
Calo
G
G
Guerrini
R
R
Strupish
J W
JW
Rowbotham
D J
DJ
Lambert
D G
DG
D000701:Analgesics, Opioid / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004558:Electric Stimulation; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D009270:Naloxone / Q000494:pharmacology; D009292:Narcotic Antagonists / Q000494:pharmacology; D009842:Oligopeptides / Q000494:pharmacology*; D018847:Opioid Peptides / Q000494:pharmacology*; D011480:Protease Inhibitors / Q000494:pharmacology; D011957:Receptors, Opioid / Q000819:agonists / Q000378:metabolism*; D014649:Vas Deferens / Q000187:drug effects* / Q000378:metabolism / Q000502:physiology; D014665:Vasodilator Agents / Q000494:pharmacology; D000094942:Nociceptin Receptor; D000097629:Nociceptin
D000701:Analgesics, Opioid; D009270:Naloxone; D009292:Narcotic Antagonists; D009842:Oligopeptides; D018847:Opioid Peptides; D011480:Protease Inhibitors; D011957:Receptors, Opioid; D014665:Vasodilator Agents; D000094942:Nociceptin Receptor; D000097629:Nociceptin; C105293:endomorphin 1; C000722283:OPRL1 protein, human