GASEOUS 2ND-MESSENGERS IN VERTEBRATE OLFACTION

Gaseous monoxides such as nitric oxide (NO) and carbon monoxide (GO) a re now recognized as important messengers in the nervous system, The e nzymes generating these compounds are highly expressed in the olfactor y system, including the epithelium and the main and accessory bulbs, A lthough the physiological roles of these molecules is still not entire ly clear, some important new data has recently emerged, Alternate path ways for NO action, possible interactions between NO, CO, and intermed iate proteins, and evidence suggestive of important roles for these mo lecules in development and regeneration are reviewed here, Of particul ar interest is the possible modulatory role of NO or CO in the transdu ction process, an area in which there has been an explosive growth in new data, Although it is clear that NO and CO are integral to the func tioning of the olfactory system, it is equally obvious that many of th e potential roles have yet to be clearly defined. (C) 1996 John Wiley & Sons, Inc.