MONOAMINES IN THE CAROTID BODY CELLS OF THE CAT

The presence of monoamines in the carotid body cells of the cat was investigated using histochemical methods, microspectrofluorometry and chemical analyses. Large amounts of norepinephrine (31 to 51 ng/carotid body), dopamine (122 to 131 ng/carotid body) and DOPA (86 to 150 ng/carotid body) were found in pooled tissues analyzed with specific chemical techniques. The majority of the glomus cells exhibited an intense fluorescence after formaldehyde treatment, having a spectrum characteristic of catecholamines. Some, but not all, of these cells gave a fluorescence reaction with the trihydroxyindole histochemical method. It is concluded that most of the glomus cells contain norepinephrine or DOPA or a combination of these two compounds while some cells contain only dopamine. A few yellow fluorescent cells were also found after formaldehyde treatment which probably contain 5-hydroxytryptamine.