title: Effects of chronic hypoxia on opioid peptide and catecholamine levels and on the release of dopamine in the rabbit carotid body.
abstract: Carotid body catecholamine and opioid levels were measured in rabbits exposed for 8 days to an atmosphere of 11% O2 in N2 (PO2 of approximately 80 mm Hg) and during an identical period of recovery, i.e., after 8 days of returning to the control normoxic atmosphere. Carotid bodies show a decrease in dopamine content at day 2. Thereafter, the levels of this biogenic amine increase progressively to peak at day 10, that is, 2 days after returning to a normoxic atmosphere. Finally, dopamine levels start to decrease and reach prehypoxic control levels at day 16, that is, after 8 days of recovery. In contrast, levels of native opioid peptides remain unchanged during the whole duration of the experiment, except for a decrease at day 2 of the hypoxic exposure. Levels of total opioid peptides are also below control values at day 2 of hypoxia, increase above control values on returning to a normoxic atmosphere (maximal levels at days 10-12), and later decrease to reach prehypoxic levels at day 16. As a result of these changes the ratios of dopamine to opioid levels show a progressive increase from day 0 to day 10 of the experiment and then return to control prehypoxic values. Carotid bodies isolated from animals that have been exposed to hypoxia for 8 days synthesize [3H]dopamine from its natural precursor [3H]tyrosine at a rate of 175 pmol/mg of protein/h, which is about double the rate of synthesis found in the carotid bodies of control animals and those allowed to recover for 8 days.(ABSTRACT TRUNCATED AT 250 WORDS)
authors: Departamento de Bioquímica y Biología Molecular y Fisiologia, Facultad de Medicina, Universidad de Valladolid, Spain.
authors: P R
authors: PR
authors: González-Guerrero
authors: R
authors: R
authors: Rigual
authors: C
authors: C
authors: González
mesh_terms: D000818:Animals; D002344:Carotid Body / Q000378:metabolism*; D002395:Catecholamines / Q000378:metabolism*; D002908:Chronic Disease; D004298:Dopamine / Q000378:metabolism*; D004723:Endorphins / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D010100:Oxygen / Q000494:pharmacology; D011817:Rabbits; D012016:Reference Values
chemical_list: D002395:Catecholamines; D004723:Endorphins; D010100:Oxygen; D004298:Dopamine