Carnosine-like immunoreactivity in human olfactory mucosa.

By means of immunohistochemical techniques it is demonstrated for the first time ever that carnosine (beta-alanyl-L-histidine)-like immunoreactivity (LI) is localized in the olfactory receptor neuron in human olfactory mucosa. Carnosine-LI was found in all regions of the receptor cells, i.e. in dendrites, olfactory vesicles, soma and axons. Supporting cells and basal cells were not immunoreactive. The present results suggest that carnosine play a major role in the human olfactory neuron and supports the concept that this peptide is a putative neurotransmitter in vertebrate olfactory systems.