Which sympathoadrenal abnormalities of adult spontaneously hypertensive rats can be traced to a prehypertensive stage?

0507549 - FGÚ 2020 RIV JP eng J - Journal Article
Vavřínová, Anna - Behuliak, Michal - Bencze, Michal - Vaněčková, Ivana - Zicha, Josef
Which sympathoadrenal abnormalities of adult spontaneously hypertensive rats can be traced to a prehypertensive stage?
Hypertension Research. Roč. 42, č. 7 (2019), s. 949-959. ISSN 0916-9636. E-ISSN 1348-4214
R&D Projects: GA ČR(CZ) GJ16-10349Y
Institutional support: RVO:67985823
Keywords : sympathoneural * autonomic nervous system * hypertension * SHR * catecholamines
OECD category: Cardiac and Cardiovascular systems
Impact factor: 2.941, year: 2019
Method of publishing: Limited access
https://www.nature.com/articles/s41440-018-0198-y

Alterations of sympathoadrenal and sympathoneural systems have been suggested to be involved in the pathogenesis of hypertension in spontaneously hypertensive rats (SHR). To evaluate the ontogenetic changes of these systems, mRNA and protein expressions of catecholaminergic system genes were measured in adrenal glands and sympathetic ganglia, and the catecholamine levels were determined in adrenal glands, sympathetic ganglia and plasma of prehypertensive (4-week-old) and hypertensive (24-week-old) SHR. Vascular sympathetic innervation was visualized in the femoral artery by glyoxylic acid. In the adrenal glands of prehypertensive SHR, the expression of catecholamine biosynthetic enzymes Ddc, Dbh and Pnmt was lower than in aged-matched Wistar-Kyoto rats. In contrast, the adrenal content of dopamine, noradrenaline and adrenaline was higher in prehypertensive SHR (141%, 123% and 120% of Wistar-Kyoto rats, respectively, p < 0.01). In the adrenal glands of adult SHR, the expression of catecholamine biosynthetic enzymes Th, Ddc, Dbh and Pnmt was decreased along the amounts of dopamine and noradrenaline (50% and 38%, respectively, p < 0.001). The expression levels of Ddc and Dbh enzymes were also downregulated in the sympathetic ganglia of both prehypertensive and adult SHR. At both ages, the density of sympathetic innervation was twofold higher in SHR compared to Wistar-Kyoto rats (p < 0.001). In conclusion, adrenal catecholamine content was increased in prehypertensive SHR, whereas it was reduced in SHR with established hypertension. Surprisingly, downregulation of catecholamine biosynthetic enzymes was observed in both the adrenal medulla and sympathetic ganglia of SHR at both ages. Thus, this downregulation might be a compensatory mechanism that counteracts the vascular sympathetic hyperinnervation seen in SHR of both ages.
Permanent Link: http://hdl.handle.net/11104/0298526