Description of Research Expertise

The unit structure in carotid and aortic bodies consists of several epithelioid cells often innervated by a single nerve fiber and surrounded by a few supporting cells. Low oxygen and high carbon dioxide pressures increase discharge frequency of the nerve fiber, and the effect of one stimulus is augmented by another. The physiological function of this cellular response is to monitor oxygen and carbon dioxide pressures in the arterial blood and generate appropriate systemic reflexes. The focus of laboratory research is on the mechanisms by which oxygen and carbon dioxide elicit the cellular response and to identify the cellular components responsible for the response. A working hypothesis is that oxygen sensor is located within the glomus cell, and the sensing mechanism involves oxygen metabolism which controls release of the neurotransmitter. Carbon dioxide detection is mediated by a separate but closely related mechanism. A link between oxygen and carbon dioxide chemoreception presumably exists at the level of a protein receptor near the synaptic junction between the glomus cells and the nerve. The identification of the mechanisms will be aided by the fact that oxygen sensitive mechanism will show adaptive structural and functional responses to chronic stimuli of low and high oxygen pressures. The study uses biochemical, biophysical and cytological techniques.