Profiles for ATP and Adenosine Release at the Carotid Body in Response to O2 Concentrations
Excitatory effects on carotid body (CB) chemotransduction have been described for both adenosine and ATP. Adenosine when applied exogenously increases carotid sinus nerve (CSN) discharges in the cat, in vivo (McQueen and Ribeiro, 1983) and in vivo (Runold et al., 1990). Administration of adenosine and drugs that increase its endogenous levels stimulate ventilation in rats, an effect abolished by the section of CSN and mediated by A2 receptors (Monteiro and Ribeiro, 1987, 1989; Ribeiro and Monteiro, 1991). In humans, the intravenous infusion of adenosine causes hyperventilation and dyspnoea, an effect attributed to the activation of CB (Watt and Routledge, 1985, Watt et al., 1987; Maxwell et al., 1986; 1987, Uematsu et al., 2000). The excitatory effect of ATP at the CB described by Zhang et al. (2000) in co-cultures of type I cells with petrosal neurons was further supported by the finding that mice deficient in P2X2 showed a markedly attenuated ventilatory response to hypoxia (Rong et al., 2003) and by the detection of hypoxia- evoked ATP release from chemoreceptor cells of the rat carotid body (Buttigieg and Nurse, 2004).
KeywordsCarotid Body Extracellular Calcium Ventilatory Response Superior Cervical Ganglion Arterial Tissue
Unable to display preview. Download preview PDF.
- Maxwell D. L., Fuller R. W., Conradson T-B., Dixon C. M. S., Aber V., Hughes M. B. and Barnes P. J. (1987) Contrasting effects of two xanthines, theophyline and enprofylline, on the cardio-respiratory stimulation of infused adenosine in man. Acta Physiol. Scand. 131: 459–465.PubMedCrossRefGoogle Scholar
- Ribeiro, J.A. and Monteiro, E.C., 1991. On the adenosine receptor involved in the excitatory action of adenosine on respiration: antagonist profile. Nucleosides Nucleotides, 10: 945–953.Google Scholar