title: Angiotensin II pressor response in the L-NAME-induced hypertensive pithed rat: role of the AT1 receptor.
abstract: The blockade of renin-angiotensin system by pharmacological interventions with angiotensin converting-enzyme (ACE) inhibitors or AT1 receptor antagonists in the juvenile critical age may attenuate or even prevent the development of hypertension. In this work, we determined the Ang II type 1 (AT1) receptor role in L-NAME-induced hypertension in pithed rats. Male Wistar rats (250-300 g) were used. Rats were divided into the following groups: Control (tap water) and N(omega)-Nitro-L-arginine methyl ester (L-NAME, 60 mg/kg/day/2 weeks). Dose-response curves to Ang II were constructed in the pithed rat. The results show that Ang II evoked blood pressure increase in pithed rats in a dose-related manner. In L-NAME-treated rats a greater maximal effect was observed, indicating that L-NAME promotes Ang II hypersensitivity. In L-NAME-treated rats, Ang II response was blocked by losartan (1 and 3 mg/kg), a selective AT1 receptor antagonist, indicating that AT1 receptor influence L-NAME hypertensive mechanism. Our results suggest that Ang II hypersensitivity in L-NAME-induced hypertension can be due to increased AT1 receptor expression or sensitivity changes.
authors: Laboratorio de Farmacología, Instituto de Investigaciones Químico Biológicas, Universidad Michoacana de San Nicolás de Hidalgo, México.
authors: Edgar Saúl
authors: ES
authors: Figueroa-Guillén
authors: Patricia
authors: P
authors: Castro-Moreno
authors: Felipe Francisco
authors: FF
authors: Rivera-Jardón
authors: Itzell A
authors: IA
authors: Gallardo-Ortiz
authors: Maximiliano
authors: M
authors: Ibarra-Barajas
authors: Daniel
authors: D
authors: Godínez-Hernández
mesh_terms: D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1 / Q000502:physiology*
chemical_list: D044140:Receptor, Angiotensin, Type 1; D000804:Angiotensin II; D019331:NG-Nitroarginine Methyl Ester