Adenosine A1 receptor distribution in the nucleus tractus solitarii of normotensive and spontaneously hypertensive rats

Adenosine acts at many sites to modulate neuronal activity. The nucleus tractus solitarii (NTS) is a major brain site in cardiovascular control. The present study was undertaken for a detailed analysis of the distribution of A1 adenosine receptor (A1R) in the NTS of spontaneously hypertensive rats (SHR) and Wistar Kyoto (WKY), using in vitro autoradiography with [3H]DPCPX. The density of [3H]DPCPX in the whole NTS decreased according to the rostral-caudal levels. This high level of [3H]DPCPX binding at rostral sites is due to an specific label of the dorsomedial/dorsolateral subnuclei. On the other hand, analysis of subpostremal subnucleus, showed opposite results. The density of [3H]DPCPX binding in the subpostremal NTS increased according to the rostral-caudal levels. Furthermore, it was observed an increased [3H]DPCPX binding in the SHR compared with WKY. The results show a complex pattern of A1R distribution in the NTS, which highlight the powerful modulatory actions mediated by adenosine in the NTS barosensitive neurons.