Jacobowitz D M, Helke C J
Brain Res Bull. 1980 Mar-Apr;5(2):195-7. doi: 10.1016/0361-9230(80)90192-6.
Immunofluorescent histochemical observation of the rat carotid body revealed the presence of substance P immunoreactive fibers. This supports the hypothesis that substance P is a neurotransmitter of chemoreceptor afferent nerves.