Perspectives in carotid body research

1984.-This review deals with some basic mechanisms that are operative in carotid body chemoreception. It describes the evolution of concepts and different hypotheses or theories developed to explain possible mechanisms responsible for the onset of sensory discharges in the carotid nerve. Unfor-tunately, no single hypothesis has been proved beyond doubt, and this may explain their variety. At present, we do not know why this task has been so difficult, although one may think of several possibilities. 1) Carotid body chemoreceptors are anatomically complex being formed by glomus (type I) and sustentacular (type II) cells. Branches of the carotid (sinus) nerve innervate the glomus cells forming sensory synapses oriented in either or both directions and the junction is enveloped by processes of the susten-tacular cells. 2) Chemoreceptors are polymodal, since they respond to a variety of natural and chemical stimuli. 3) It is possible that various stimuli may act on different elements of the receptor complex. 4) It is also possible that stimuli may act using different mechanisms. In addition, the multitud