Carnosine (.beta.-Ala-L-His) is localized within the receptor neurons of the primary olfactory system. Carnosine synthetase, the enzyme responsible for its synthesis, is found in the primary olfactory pathway of the mouse at activities higher than that found in other body tissues and brain regions. Carnosinase, the degradative enzyme, was present at high activities, only in the olfactory epithelial portion of this pathway. Peripheral deafferentation or central denervation caused a selective decrease in the activity of carnosine synthetase in the reciprocal portion of the primary olfactory system implying specific localization within the receptor neurons. Carnosine may have a role in olfactory neural transmission.
