Nitric oxide as an inhibitory non-adrenergic non-cholinergic neurotransmitter

Abstract

Inhibitory non-adrenergic non-cholinergic (NANC) nerves are thought to be important in the autonomic innervation of the gastrointestinal tract and other organ systems. The nature of their neurotransmitter is still debated. Speculation that nitric oxide (NO), formed from L-arginine in neuronal structures and other cells, could act as a neurotransmitter, is not yet supported by demonstration of its release upon nerve stimulation. Using a superfusion bioassay, we report the release of a vasorelaxant factor upon stimulation of the NANC nerves in the canine ileocolonic junction. Several pieces of evidence, including the selectivity of the bioassay tissues, chemical instability, inactivation by superoxide anion and haemoglobin, inhibition by NG-nitro-L-arginine (L-NNA) and potentiation by L-arginine all indicated that NO accounted for the biological activity of this transferable NANC factor.

A novel pathogenesis of megacolon in Ncx/Hox11L.1 deficient mice.

“…Thus, functions of the ganglia were analyzed by examining the production of NADPH diaphorase and substance P in the neuronal cells. NADPH diaphorase is identical to nitric oxide synthase (26)(27)(28)(29) and nitric oxide functions as an inhibitory neurotransmitter to relax smooth muscle (30), while substance P is an excitatory neurotransmitter to contract circular smooth muscles (31,32). NADPH diaphorase positive neuronal cells were dense in the proximal colon of Ncx Ϫ / Ϫ mice with (data not shown) or without megacolon (Fig.…”

Nitric oxide‐dependent relaxation induced by M1 muscarinic receptor activation in the rat small intestine

“…Nitric oxide (NO) has been suggested as a mediator in autonomic neurotransmission (Bult et al, 1990;Gillespie et al, 1989;Li & Rand, 1989). It has now become evident that nitrergic nerves account for a substantial part of inhibitory transmission in the gastrointestinal tract (Sanders & Ward, 1992), in the urogenital tract (Andersson, 1993;Ignarro et al, 1990), in the respiratory tract (Belvisi et al, 1995) and in arteries (Toda & Okamura, 1990).…”

Intracavernous administration of SIN-1+VIP in an in vivo rabbit model for erectile function

“…13 It has been proven that NO is the neurotransmitter responsible for the NANC activity in the peripheral nervous system of various organs. 14 The localisation of NOS in the peripheral autonomic nerves innervating vascular and nonvascular smooth muscle was further confirmation of the NANC activity of NO. 15 Electrical stimulation of human corpus cavernosum tissue with disrupted endothelium and in the presence of muscarinic adrenergic blockade results in NANC neurogenic relaxation.…”