[Nitric oxide and carbon monoxide--a new class of signal molecules].

Recent data concerning the physiological, biochemical and pathological aspects of NO and CO in the brain are reviewed. Among them: biosynthesis, regulation and localization of corresponding enzymes (NOS, GO-2) and also cGMP in discrete populations of neurons; interrelationship between glutamate, NMDA-receptors, NO and CO; the role of NO and CO in different physiological and pathological processes in the nervous system, etc. On the basis of data obtained during the last several years, a conception of NO and CO as a novel class of signal molecules operating as neuromediators and/or retrograde transsynaptic messengers is discussed.