Caffeine is the most commonly psychoactive drug, an habitual drink in high altitude sporting, and when acutely taken, it causes profound alterations in carotid body (CB) function and ventilation via adenosine receptors antagonism. In the present work we have investigated the effects of chronic caffeine ingestion in catecholamine (CA) dynamics in the carotid body of control and chronic hypoxic rats. Four groups of animals were used: normoxic (N), caffeine-treated normoxic (1 mg/mL in drinking water 15 days; CafN), chronic hypoxic (CH, 12%O2, 15 days) and chronically hypoxic-caffeine-treated (CafH).. Caffeine intake in controls rats did not modify CA content, synthesizing, and releasing responses, and the expression of tyrosine hydroxylase. CH increased dopamine content, synthesis, and basal and acute hypoxia-induced release; chronic caffeine ingestion augmented CH effects. Findings indicate that chronic caffeine ingestion in normoxic rats did not modify dopamine dynamics at the CB, but increases dopaminergic system during chronic hypoxia.
Catecholamines Carotid body Caffeine Chronic hypoxia
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We want to thank Mª de los Llanos Bravo for technical assistance. The work was supported by BFU2007-61848 (DGICYT), JCyL-GR242, CIBER (FISS-ICiii) and Spanish MEC/Portugal CRUP 2009–0172.
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1.CEDOC, Departamento de Farmacologia, Faculdade de Ciências MédicasUniversidade Nova de LisboaLisbonPortugal
2.Departamento de Bioquímica y Biología Molecular y Fisiología, Universidad de Valladolid, Facultad de Medicina, Instituto de Biología y Genética MolecularCSIC. Ciber de Enfermedades Respiratorias, CIBERES, Instituto de Salud Carlos IIIValladolidSpain