The medial nucleus of amygdala (MeA) mediate the cardiovascular responses evoked by noradrenaline microinjected into the lateral septal area (LSA) in rats

Abstract

IntroductionWe demonstrated that the microinjection of noradrenaline into the LSA evoked pressor and bradycardic responses mediated by vasopressin release. Moreover, the microinjection of cobalt or selective non‐NMDA antagonist NBQX into the paraventricular nucleus (PVN) blocked the pressor response and bradycardia evoked by NA injected into the LSA, suggesting the PVN as the final structure in this pathway. Anatomical dates demonstrated that no direct connections were observed between the LSA and the PVN or the SON. The MeA is a structure involved in cardiovascular control. Projections from the LS to the MeA have also been described in the literature and MeA sends projections to PVN.ObjectiveTo investigate if MeA acute ablation by the injection of cobalt blocked the cardiovascular responses to NA microinjection into the LSA.Methods and ResultsMale Wistar rats were used. Cannulaes was implanted in the LSA and the ipsilaterally in the MeA using a stereotaxic apparatus A catheter was implanted into the femoral artery for blood pressure and heart rate recording. The microinjection of cobalt into the MeA blocked the pressor and bradycardiac responses evoked by NA microinjection into the LSA.ConclusionOur results suggest that synapses in the MeA are involved in the mediation of the pressor and bradycardiac response to the microinjection of NA into the LSA.Financial SupportCAPES and FAEPA.