The Role of Nitric Oxide in the Peripheral Nervous System

Abstract

The term “nitrergic”, initially coined by (1992) to describe nerves whose transmission process utilises the L-arginine-nitric oxide (NO) pathway, has now gained acceptance by the International Union of Pharmacology Committee on Nomenclature of the Pharmacology of Nitric Oxide (MONCADA et al. 1997). As was the case when (1933) proposed the terms adrenergic and cholinergic, nitrergic was introduced to facilitate classification and discussion and not to indicate the precise chemical nature of the neurotransmitter involved. Indeed, as will be discussed, intense debate has raged as to whether the nitrergic transmitter is NO per se or a NO-like molecule. Most of the major objections to acceptance of NO, however, now seem to have been largely overcome. The term nitrergic is, however, far from ideal. Although seemingly appropriate in circumstances where a particular transmission process is wholly explained by the L-arginine-NO pathway, it appears less so in situations of co-transmission both in the periphery and central nervous system (CNS), where this pathway is not the sole or even the dominant mechanism for transmission. Nevertheless, in the absence of a more suitable alternative, the term nitrergic is employed here to include any nerve that utilises the L-arginine-NO pathway, irrespective of the co-involvement of additional neurotransmitters.