Distributed chemoreceptor neuron

Johnson E.W., Eller P. and Jafek B. (1995). Distribution of OMP, PGP 9.5- and CaBP-like immunoreactive chemoreceptor neurons in the developing human olfactory epithelium. Anat Embryol 191, 311-317. 

Crustaceans perceive chemical signals with olfactory receptors - limited to the aesthetasc hairs that only contain chemoreceptor neurons and are located on the antennae - or with other chemoreceptors situated in setae that are distributed over the body surface ( distributed chemoreceptors including contact chemoreceptors, Schmidt and Mellon, Chap. 7 Hallberg and Skog, Chap. 6). Contact chemoreceptors contain both chemoreceptor neurons and mechanoreceptive neurons (Schmidt and Mellon, Chap. 7). 

In conclusion, the distribution of NOS immunoreactivity and the pharmacological and physiological evidence analyzed and discussed here support the proposal that CB endogenous NO exerts a tonic inhibitory effect on CB chemoreception. Clearly, NO in low concentration is a broad inhibitory modulator of the chemoreception process in the CB. NO may modulate chemoreception by regulating the CB vascular tone, the oxygen delivery to the chemoreceptor cells, and the excitability of glomus cells and petrosal sensory neurons. 

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