Change in the expression of NPY receptor subtypes Y1 and Y2 in central and peripheral neurons related to the control of blood pressure in rats following experimental hypertension.

Neuropeptide Y (NPY) is known to participate in central mechanisms of blood pressure control. However, variations on the expression of its receptors in response to a hypertensive challenge are not well defined, specially when considering that Y1 and Y2 often mediate opposite responses. In this study we have employed in situ hybridization to analyze changes in mRNA expression of NPY receptor subtypes Y1 and Y2 in the nucleus tractus solitarii (NTS), paraventricular nucleus of the hypothalamus (PVN) and petrosal and nodose ganglions 2 h, 3 and 7 days after aortic coarctation induced hypertension. Quantification by image analysis showed significant differences between sham-operated and aortic-coarcted hypertensive rats. Y1 receptor mRNA expression was increased (39%) in petrosal ganglion, 3 days after surgery. Y2 receptor mRNA expression was increased (143%) in the NTS of hypertensive compared with sham rats 2 h after surgery. Y2 receptor mRNA was decreased (62%) in the nodose ganglion of hypertensive compared with sham rats 2 h after surgery. No change was seen in Y1 and Y2 mRNA expression in the PVN in any analyzed period. The data suggest that NPY Y1 and Y2 receptors might participate in the mechanisms involved in the establishment/maintenance of hypertension induced by aortic coarctation. Acute changes seem to be involved with the adaptation to the new hypertensive state.