Article date: January 1991
By: Chun Guang Li, Michael J. Rand, in Volume 102, Issue 1, pages 91-94
The nitric oxide (NO) synthesis inhibitors NG‐monomethyl l‐arginine (l‐NMMA) and l‐nitroarginine methyl ester (l‐NAME) reduced relaxations of guinea‐pig tracheal smooth muscle elicited by stimulation of intramural non‐adrenergic, non‐cholinergic (NANC) nerves, but d‐NMMA had no effect. l‐NAME was 10–30 times more potent than l‐NMMA. Relaxations produced by sodium nitroprusside and vasoactive intestinal polypeptide (VIP) were not affected by l‐NMMA or l‐NAME.
The inhibitory effect of l‐NMMA on NANC‐mediated relaxations was partially reversed by l‐arginine but was not affected by d‐arginine.
VIP antibody and α‐chymotrypsin abolished or greatly reduced the relaxant action of VIP and reduced relaxations elicited by stimulation of NANC nerves; the residual NANC relaxation was further reduced by l‐NAME.
The results suggest that NO and VIP are mediators of NANC‐induced relaxations of guinea‐pig tracheal smooth muscle. We propose the term ‘nitrergic’ to describe transmission processes which are mediated by NO.
The nitric oxide (NO) synthesis inhibitors NG‐monomethyl l‐arginine (l‐NMMA) and l‐nitroarginine methyl ester (l‐NAME) reduced relaxations of guinea‐pig tracheal smooth muscle elicited by stimulation of intramural non‐adrenergic, non‐cholinergic (NANC) nerves, but d‐NMMA had no effect. l‐NAME was 10–30 times more potent than l‐NMMA. Relaxations produced by sodium nitroprusside and vasoactive intestinal polypeptide (VIP) were not affected by l‐NMMA or l‐NAME.
The inhibitory effect of l‐NMMA on NANC‐mediated relaxations was partially reversed by l‐arginine but was not affected by d‐arginine.
VIP antibody and α‐chymotrypsin abolished or greatly reduced the relaxant action of VIP and reduced relaxations elicited by stimulation of NANC nerves; the residual NANC relaxation was further reduced by l‐NAME.
The results suggest that NO and VIP are mediators of NANC‐induced relaxations of guinea‐pig tracheal smooth muscle. We propose the term ‘nitrergic’ to describe transmission processes which are mediated by NO.
DOI: 10.1111/j.1476-5381.1991.tb12137.x
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