Nitric oxide as a neurotransmitter in peripheral nerves : nature of transmitter and mechanism of transmission

We coined the adjectival term nitrergic to describe the mode of transmission that involves nitric oxide (NO) and, by extension, the transmitter and the nerves from which it originates (100, 135, 136). This term is noncommittal about the exact nature of the transmitter, as was the case when Dale coined the tenns cholinergic and adrenergic (42). It is advisable at the outset to alert the reader to our opinion that NO as such is not likely to be the substance that mediates transmission, that is, conveys a message from nerve terminals across the neuroeffector junction to the responding smooth muscle cells. Instead, the mediator appears to be a NO donor that acts as a carrier for NO from its site of formation to its site of action. The evidence for this assertion is presented below. We have used the term nitrergic when our appraisal of the balance of the evidence indicates that it is justified.