Catecholaminergic and angiotensinergic systems are involved in the neural control of blood pressure. The present study analysed the expression of
tyrosine hydroxylase (TH), a key
enzyme for
catecholamine synthesis and of
angiotensinogen (AGT), the precursor of
angiotensin II (Ang II), in areas of the central nervous system (CNS) involved with cardiovascular regulation such as nucleus tractus solitarius (NTS), ventrolateral medulla (VLM), locus coeruleus (LC) and hypothalamic paraventricular nucleus (PVN) 2 h, 3 and 7 days after aortic coarctated hypertensive rats. In situ hybridization, was employed for the analysis of
messenger RNA (
mRNA) expression with anatomical resolution. No changes were seen in TH and AGT
mRNA expression in the analysed areas 2 h and 3 days after
aortic coarctation when compared to the respective
sham group. TH
mRNA expression was increased in the NTS and LC of rats 7 days after coarctation
hypertension when compared to
sham rats. Time course analysis, showed an increase in TH
mRNA expression in the NTS 7 days after
aortic coarctation when compared to 2 h and 3 days groups, as well as an increase in LC 3 days and 7 days following coarctation
hypertension in comparison with the 2 h group. Analysis of AGT
mRNA in the NTS expression revealed a decrease at 3 days, followed by an increase in
mRNA expression 7 days following coarctation
hypertension when compared to the
sham group. Time course analysis, showed an increase in AGT
mRNA expression in the NTS 7 days after coarctation when compared to 2 h and 3 days groups. The results show that TH and AGT
mRNA expression changes during the different phases of experimental
hypertension, suggesting that the
noradrenaline (NOR) and
angiotensin II (Ang II) might participate in the modulation/maintenance of coarctation
hypertension.