Nitric oxide is involved in the non-adrenergic, non-cholinergic inhibitory neurotransmission of the pig intravesical ureter.
NADPH-diaphorase histochemical staining and electrical field stimulation (EFS) were performed in vitro to investigate whether nitric oxide (NO) is involved in non-adrenergic non-cholinergic (NANC) inhibitory neurotransmission of pig intravesical ureter. NADPH-diaphorase activity was expressed in nerve trunks and thin nerve fibres around arteries and muscular bundles in the intravesical ureter. Relaxations to EFS were tetrodotoxin (10(-6) M)-sensitive which indicates their neurogenic origin. Addition of the NO-synthase inhibitor, L-NG-nitroarginine (L-NOARG, 3 x 10(-5) M), abolished the electrically induced relaxations, which were significantly reversed by L-arginine (3 x 10(-3) M). Addition of acidified sodium nitrite (NaNO2, 10(-5)-10(-3) M) evoked concentration-dependent relaxations of ureteral strips which were unaffected by L-NOARG. It is concluded that NO synthase is present in nerve fibres and NO seems to mediate the inhibitory neurotransmission of the porcine intravesical ureter.
Hernández
M
M
Departamento de Fisiología, Facultad de Veterinaria, Universidad Complutense, Madrid, Spain.
Prieto
D
D
Orensanz
L M
LM
Barahona
M V
MV
García-Sacristán
A
A
Simonsen
U
U
D000818:Animals; D001120:Arginine / Q000031:analogs & derivatives / Q000494:pharmacology; D001341:Autonomic Nervous System / Q000502:physiology*; D004558:Electric Stimulation; D005260:Female; D006651:Histocytochemistry; D066298:In Vitro Techniques; D008297:Male; D009126:Muscle Relaxation / Q000502:physiology; D009130:Muscle, Smooth / Q000294:innervation / Q000502:physiology*; D009252:NADPH Dehydrogenase / Q000378:metabolism; D009569:Nitric Oxide / Q000037:antagonists & inhibitors / Q000502:physiology*; D019335:Nitroarginine; D013552:Swine; D009435:Synaptic Transmission / Q000502:physiology*; D016707:Tissue Fixation; D014513:Ureter / Q000294:innervation / Q000502:physiology*
D019335:Nitroarginine; D009569:Nitric Oxide; D001120:Arginine; D009252:NADPH Dehydrogenase