Quantitative autoradiography of adrenergic, neuropeptide Y and angiotensinII receptors in the nucleus tractus solitarii and hypothalamus of rats with experimental hypertension
Rs. Almeida et al., Quantitative autoradiography of adrenergic, neuropeptide Y and angiotensinII receptors in the nucleus tractus solitarii and hypothalamus of rats with experimental hypertension, GEN PH-VASC, 34(5), 2000, pp. 343-348
Catecholamines, neuropeptide Y (NPY) and angiotensin II (Ang II) are known
to participate in the central control of blood pressure. However, the modul
ation of these neurotransmitter receptors in response to a hypertensive sti
mulus is not appropriately established. The purpose of the present study wa
s to examine binding parameters of alpha (2)-adrenergic, NPY acid Ang II re
ceptors in the nucleus tractus solitarii (NTS) and paraventricular hypothal
amic nucleus (PVN) following a hypertensive stimulus in the aortic-coarcted
rat by means of quantitative receptor autoradiography. No changes were see
n in binding parameters of alpha (2)-adrenergic and NPY receptors in the NT
S of the hypertensive rat compared to control. However, an increased affini
ty (54%) of noradrenaline competing for H-3-PAC was seen in the PVN. Moreov
er, an increased binding (49%) of I-125-PYY was also observed in the PVN. T
he affinity of Ang II for I-125-Sar(1)IleS-Ang II binding sites was also in
creased (57%) in the NTS of the hypertensive rat. No changes in the binding
parameters of radioactive Ang II were observed in the PVN. The results sug
gest that systems involved with hypertension like Ang II in the NTS and cat
echolamines in the PVN might collaborate in the development/maintenance of
high blood pressure in the aortic-coarcted rat. (C) 2001 Elsevier Science I
nc. All rights reserved.