Fate of the catecholamine stores in the rabbit carotid body superfused in vitro.

In rabbit carotid bodies (CBs) superfused during 1-5 h, with an air-equilibrated medium containing no tyrosine (TYR), the dopamine (DA) content decreased by approximately 60% after 1 h and remained constant afterwards. TYR and 3,4-dihydroxyphenylacetic acid (DOPAC) decreased with the same time course. Noradrenaline (NA) content exhibited a biphasic decrease of lesser magnitude than that of DA.

Comparison of the monoamine and catabolite content in the cat and rabbit carotid bodies.

The monoamine and catabolite contents of a large number of rabbit (n = 95) and cat (n = 32) carotid bodies (CBs) have been measured by high performance liquid chromatography with electrochemical detection (HPLC-ED). The dopamine (DA) content as well as that of its precursors tyrosine (TYR), dihydroxyphenylalanine (DOPA) and catabolites dihydroxyphenylacetic acid (DOPAC), homovanilic acid (HVA) were approximately equal in both species. The noradrenaline (NA) content was 10 times larger in the cat than in the rabbit CBs.

Rate of dopamine metabolism in the rabbit carotid body in vivo.

In the rabbit carotid body (CB) in vivo, the rate of dopamine metabolism was estimated to 44.4 +/- 3.9 (SD) pmol/CB/h from the decrease in dihydroxyphenylacetic acid content after pargyline inhibition of monoamine oxidase.

Monoamines and their catabolites in the rabbit carotid body. Effects of reserpine, sympathectomy and carotid sinus nerve section.

Monoamines and their metabolites have been measured by high performance liquid chromatography with electrochemical detection, in control rabbit carotid bodies and under several experimental conditions: 1) at different times (3 h, 6 h, 24 h, 48 h) after intravenous injection of reserpine (5 mg/kg); 2) 14 days after sympathectomy; 3) 14 days after section of the carotid sinus nerve. The results were analyzed with probability plotting methods. Dopamine was the most important monoamine in the carotid body (CB) and its variations were very large.