Expression of P2X 2 and P2X 3 receptors in the rat carotid sinus, aortic arch, vena cava, and heart, as well as petrosal and nodose ganglia

Abstract

With single-and double-labeling immunofluorescence techniques, the distribution patterns and morphological characteristics of P2X 2-and P2X 3-immunoreactive nerve fiber terminals and neuronal bodies have been studied in the main circulatory system baroreceptors and the nodose and petrosal ganglia of rats. A high density of P2X 2-and P2X 3-immunoreactive nerve fiber terminals was detected in the carotid sinus. P2X 2-and P2X 3-immunoreactive nerve fiber terminals were also distributed widely in the aortic arch, atrium, vena cava, and ventricles. Almost all the P2X 2-immunoreactive nerve fiber terminals were immunoreactive for P2X 3 receptors. P2X 2-and P2X 3-immunoreactive neuronal bodies were also detected in the nodose and petrosal ganglia, which are the sources of the P2X 2-and P2X 3-immunoreactive nerve terminals. P2X 2 and P2X 3 receptors were expressed in the same ganglionic neurons. These data indicate that extracellular ATP, via the homomeric P2X 2 and P2X 3 receptors, and heteromeric P2X 2/3 receptor in the sensory receptors of carotid sinus, aortic arch, atrium, and vena cava, may be involved in the regulation of systematic circulation blood pressure. © 2011 Springer Science+Business Media B.V.