Blood pressure reduction induced by chronic intracerebroventricular or peroral clonidine administration in rats with salt-dependent or angiotensin II-dependent hypertension

Title:

Blood pressure reduction induced by chronic intracerebroventricular or peroral clonidine administration in rats with salt-dependent or angiotensin II-dependent hypertension

Creator:

Zicha, Josef, Řezáčová, Lenka, Behuliak, Michal, and Vaněčková, Ivana

Identifier:

https://cdk.lib.cas.cz/client/handle/uuid:ff559a62-2846-4eb0-9e23-daad50433527
uuid:ff559a62-2846-4eb0-9e23-daad50433527
doi:10.33549/physiolres.935041

Subject:

central α2-adrenergic receptors, sympathetic tone, Dahl saltsensitive rats, Ren-2 transgenic rats, vasoactive systems, renin-angiotensin system, sympathetic nervous system, and nitric oxide

Type:

model:article and TEXT

Format:

počítač and online zdroj

Description:

The agonists of α2-adrenergic receptors such as clonidine, rilmenidine or monoxidine are known to lower blood pressure (BP) through a reduction of brain sympathetic outflow but their chronic antihypertensive effects in rats with low-renin or highrenin forms of experimental hypertension were not studied yet. Moreover, there is no comparison of mechanisms underlying BP reduction elicited by chronic peroral (po) or intracerebroventricular (icv) clonidine treatment. Male salt-sensitive Dahl rats fed a high-salt (4% NaCl) diet and Ren-2 transgenic rats were treated with clonidine administered either in the drinking fluid (0.5 mg/kg/day po) or as the infusion into lateral brain ventricle (0.1 mg/kg/day icv) for 4 weeks. Basal BP and the contributions of renin-angiotensin system (captopril 10 mg/kg iv) or sympathetic nervous system (pentolinium 5 mg/kg iv) to BP maintenance were determined in conscious cannulated rats at the end of the study. Both peroral and intracerebroventricular clonidine treatment lowered BP to the same extent in either rat model. However, in both models chronic clonidine treatment reduced sympathetic BP component only in rats treated intracerebroventricularly but not in perorally treated animals. In contrast, peroral clonidine treatment reduced angiotensin IIdependent vasoconstriction in Ren-2 transgenic rats, whereas it lowered residual blood pressure in Dahl rats. In conclusions, our results indicate different mechanisms of antihypertensive action of clonidine when administered centrally or systemically.

Language:

English

Rights:

http://creativecommons.org/licenses/by-nc-sa/4.0/
policy:public

Coverage:

763-770

Source:

Physiological research | 2022 Volume:71 | Number:6

Harvested from:

CDK

Metadata only:

false