Adenosine-Acetylcholine Interactions at the Rat Carotid Body
Excitatory effects on carotid body (CB) chemotransduction have been described for adenosine and acetylcholine (ACh). The importance of the excitatory effects of exogenous (Monteiro and Ribeiro, 1987) and endogenous adenosine (Monteiro and Ribeiro, 1989) observed in vivo in the rat is supported by the increase in adenosine concentrations during hypoxia (Conde and Monteiro, 2001). In response to hypoxia, the CB also releases ACh (Fitzgerald et al. 1999) that activates nicotinic receptors (Shirahata et ai 1997). ACh and nicotine increase [Ca2+] in type I cells via activation of nicotinic receptors (Dasso et al 1997) and induce the release of several neurotransmitters at the CB, e.g. catecholamines (Obeso et ai 1997). In the present work we tested the hypothesis that ACh can induce the release of adenosine from rat carotid body by a mechanism that involves the activation of nicotinic receptors.
KeywordsNicotinic Receptor Carotid Body Nicotinic Agonist Adenosine Concentration Nicotinic Antagonist
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