Contribution of Dopamine D2 Receptors for the cAMP Levels at the Carotid Body
There is a general consensus that the effects of dopamine at the carotid body (CB) are mediated by activation of both D1and D2 receptor subtypes (Gonzalez et ai. 1994). D1- and D2-like receptors have been defined traditionally by their opposing effects on the enzyme adenylate cyclase (AC), with D1-like (D1 and D5) receptors positively coupled to this enzyme, whereas D2-like (D2 D3 and D4) are either negatively coupled or uncoupled to this effector (Missale et al. 1998). Excitatory effects of exogenous dopamine (1 and 10 μM) on cyclic adenosine 3’,5’-monophosphate (cAMP) production have been described at the rabbit CB equilibrated with hyperoxia and attributed to the activation of D1 receptors (Pérez-Garcia et al. 1990; Almaraz et al. 1991). The present work was undertaken to investigate the contribution of D2 receptors to cAMP production at the rat CB in hyperoxia, normoxia and hypoxia.
KeywordsAdenylate Cyclase Carotid Body Excitatory Effect cAMP Production cAMP Content
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- Almaraz. L., Pérez-García, M.T. and González, C., 1991. Presence of D1 receptors in the rabbit carotid body. Neuroscience Letters 132:259–262.Google Scholar
- Delpiano. M.A. e Acker, H., 1984. O2 chemoreception of the cat carotid body in vitro. In: Oxygen Transport to Tissue (D.W. Lubbers et al, eds), Plenum Publishing Corporation, pp 705–717.Google Scholar
- Monteiro. E.C. and Ribeiro, J.A., 2000. Adenosine-dopamine interaction and ventilation mediated through carotid body chemoreceptors. In: Oxygen Sensing: Molecule to Man. (S. Lahiri et al., eds), Kluwer Academic/Plenum Publishers, pp 671–684.Google Scholar
- Wang. W.J., Cheng, G.F., Dinger, B.G. and Fidone, S.J., 1989. Effects of hypoxia on cyclic nucleotide formation in rabbit carotid body in vitro. Neuroscience Letters 105:164–168.Google Scholar
- Zapata P., 1997. Chemosensory activity in the carotid nerve: effects of pharmacological agents. In: The Carotid Body Chemoreceptors (C. Gonzalez, ed), Springer-Verlag, pp 119–146.Google Scholar