Dopamine Metabolism in the Rabbit Carotid Body in Vitro: Effect of Hypoxia and Hypercapnia
Dopamine (DA) and noradrenaline (NA) were measured in the rabbit carotid body (CB) in vitro by HPLC-ED under the following experimental conditions: 1 h superfusion in normoxic, hypoxic (10% O2 in N2) or hypercapnic (8% CO2, 20% O2, 72% N2) medium, 5h superfusion in normoxia or hypoxia. The contents of DA and NA were decreased by hypoxia and hypercapnia after 1 h and 5h indicating a possible DA and NA secretion. Under the same experimental conditions synthesis of DA and NA and catabolism of DA were studied with enzymatic inhibition of tyrosine hydroxylase and monoamine oxidase (MAO) respectively. In hypoxia (1 h and 5h) the rate constant of DA synthesis was the same as in normoxia; however NA synthesis was decreased after 1 h hypoxia. On the contrary, hypercapnia, appeared to be a very effective stimulus of DA and NA synthesis.
KeywordsTyrosine Hydroxylase Carotid Body Catecholamine Synthesis Carotid Sinus Nerve Catecholamine Metabolism
Unable to display preview. Download preview PDF.
- Fidone S., Gonzalez C., 1982a, Catecholamines synthesis in rabbit carotid body in vitro. J. Physiol. (London), 333: 69.Google Scholar
- Fidone S.,Gonzalez C.,Yoshizaki K., 1982b, Effects of hypoxia on catecholamine synthesis in rabbit carotid body in vitro. J. Physiol. (London), 333 81.Google Scholar
- Fidone S.J., Gonzalez C., 1986, Initiation and control of chemoreceptor activity in the carotid body;In, Handbook of Physiology, Section 3: The Respiratory system, Vol. 11. Control of Breathing, Part I, pp 247, AP. Fishman ed. Am. Physiol. Soc. Bethesda. Md.Google Scholar
- Hanbauer I., Hellstrom S., 1978, The regulation of dopamine and noradrenaline in the rat carotid body and its modification by denervation and by hypoxia. J. Physiol. (London), 282: 21.Google Scholar
- Kuno T.,Marukawa A.,Fujiwara H.,Tanaka C.,1981. Dopamine accumulation in the mouse brain during hypoxia. Japan. J. Pharmacol.. 31: 503.Google Scholar
- Miwa S., Fujiwara M., Inoue M., Fujiwara M., 1986, Effects of hypoxia on the activities of noradrenergic and dopaminergic neurons in the rat brain. J. Neurochem., 47: 63.Google Scholar
- Roumy M.,Armengaud C.,Ruckebusch M.,Sutra J.F.,Leitner L.-M.,1988, Fate of the catecholamine stores in the rabbit carotid body superfused in vitro. Pfliigers Arch., 411–436.Google Scholar