title: Tachykinin NK1 and NK2 receptors mediate inhibitory vs excitatory motor responses in human isolated corpus cavernosum and spongiosum.
abstract: Motor effects produced by tachykinins were studied in human isolated corpus spongiosum and cavernosum. In quiescent preparations neurokinin A caused potent contractions (pD(2)=8.3 - 7.9 respectively) prevented by the NK(2) receptor-selective antagonist nepadutant, whereas [Sar(9)]SP sulfone and senktide (NK(1) and NK(3) receptor-selective agonists) produced no effect or spare contractions. In KCl-precontracted corpus spongiosum septide (pD(2)=7.1) and [Sar(9)]SP sulfone (pD(2)=7.7) produced tetrodotoxin-resistant relaxations, abolished by the tachykinin NK(1) receptor-selective antagonist SR 140333. [Sar(9)]SP sulfone (1 microM) produced similar relaxations in precontracted corpus cavernosum. Electrical field stimulation (EFS) elicited tetrodotoxin-sensitive relaxations, which were additive to those produced by [Sar(9)]SP sulfone. N(omega)-nitro-L-arginine (L-NOARG) totally prevented both [Sar(9)]SP sulfone- and EFS-induced relaxations. These results show that tachykinin NK(1) and NK(2) receptors mediate opposite motor effects in human penile tissues, suggesting a possible modulatory role of tachykinins on smooth muscle tone in these organs.
authors.affiliation: Department of Pharmacology, Menarini Ricerche S.p.A., Via Rismondo 12/A, 50131 Florence, Italy. chimfarm@menarini-richerche.it
authors.forename: Riccardo
authors.initials: R
authors.lastname: Patacchini
authors.forename: Guido
authors.initials: G
authors.lastname: Barbagli
authors.forename: Enzo
authors.initials: E
authors.lastname: Palminteri
authors.forename: Massimo
authors.initials: M
authors.lastname: Lazzeri
authors.forename: Damiano
authors.initials: D
authors.lastname: Turini
authors.forename: Carlo Alberto
authors.initials: CA
authors.lastname: Maggi
mesh_terms: D000328:Adult; D004558:Electric Stimulation / Q000379:methods; D006801:Humans; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009043:Motor Activity / Q000502:physiology*; D009119:Muscle Contraction / Q000187:drug effects / Q000502:physiology*; D009126:Muscle Relaxation / Q000187:drug effects / Q000502:physiology*; D009130:Muscle, Smooth / Q000187:drug effects / Q000502:physiology*; D064729:Neurokinin-1 Receptor Antagonists; D010413:Penis / Q000187:drug effects / Q000502:physiology*; D018040:Receptors, Neurokinin-1 / Q000819:agonists / Q000502:physiology*; D018041:Receptors, Neurokinin-2 / Q000819:agonists / Q000037:antagonists & inhibitors / Q000502:physiology*; D015320:Tachykinins / Q000502:physiology; D014521:Urethra / Q000187:drug effects / Q000502:physiology
chemical_list: D064729:Neurokinin-1 Receptor Antagonists; D018040:Receptors, Neurokinin-1; D018041:Receptors, Neurokinin-2; D015320:Tachykinins