Receptor-receptor interactions in central cardiovascular regulation. Focus on neuropeptide/alpha(2)-adrenoreceptor interactions in the nucleus tractus solitarius.

The nucleus tractus solitarii (NTS) is a key nucleus in central cardiovascular control. In this mechanism it is well known the role of the alpha(2)-adrenoreceptors for the modulation of the autonomic pathways. Moreover a number of neuropeptides described in the NTS, including Neuropeptide Y (NPY), Galanin (GAL) and Angiotensin II (Ang II), have different roles in regulating the cardiovascular function within this nucleus. We show in this review several data which help to understand how these neuropeptides (NPY, GAL and Ang II) could modulate the cardiovascular responses mediated through alpha(2)-adrenoreceptors in the NTS. Also we show for the first time the interactions between neuropeptides in the brain, specifically the interactions between NPY, GAL, and Ang II, and its functional relevance for central cardiovascular regulation. These data strength the role of neuropeptides on central autonomic control and provide some evidences to understand the neurochemical mechanisms involved in the cardiovascular responses from the NTS.