EXPRESSION OF cfos IN THE MEDULLA OBLONGATA AFTER CAROTID BARORECEPTOR ACTIVATION BYELEVATED INTRASINUS PRESSURE AND ADENOSINE

Expression of cfos protein in the medulla oblongata after baroreceptor activation by elevated intrasinus pressure (ISP) and perfusion of adenosine (Ado) was examined in 14 vascularly isolated carotid sinus perfusion rats. The results showed that Foslike immunoreactive(FLI) neurons were distributed throughout nucleus tractus solitarius, area postrema, rostral ventrolateral medulla and nucleus raphe pallidus, and the number of FLI was increased with the elevation of ISP. Furthermore, perfusing the carotid sinus with Ado at a given ISP markedly increased the FLI in the above regions. From the results obtained, it is concluded that the cfos expression in baroreflex pathway in medulla oblongata may be enhanced by elevated ISP and intrasinus perfusion of Ado, and Ado is capable of facilitating the baroreflex.