Chronic but not acute treatment with hydralazine reverses the decreased endothelium-dependent responses in spontaneously hypertensive rats.
The relaxant response to acetylcholine (ACh) an endothelium dependent vasodilator agent and sodium nitroprusside (SNP), an endothelium independent vasodilator agent, of precontracted isolated aortae and mesenteric arterioles in vivo-in situ were studied in spontaneously hypertensive rats (SHR) and normotensive Wistar rats treated with hydralazine in acute (24 h) and chronic (15 d) administration. The impaired responses to ACh observed in SHR vessels were restored by chronic but not by acute treatment, whereas the SNP-induced responses were not affected. It is suggested that: 1) The acute decrease of blood pressure level per se is not sufficient to restore the impaired response to ACh; 2) The alteration of vascular response is not an irreversible phenomenon; 3) Hydralazine did not interfere with the relaxant responses to SNP.
Nigro
D
D
Department of Pharmacology, University of São Paulo, Brazil.
Fortes
Z B
ZB
Carvalho
M H
MH
Scivoletto
R
R
D000109:Acetylcholine / Q000494:pharmacology; D000818:Animals; D001160:Arterioles / Q000187:drug effects / Q000503:physiopathology; D001794:Blood Pressure / Q000187:drug effects; D004730:Endothelium, Vascular / Q000187:drug effects / Q000503:physiopathology*; D005260:Female; D006830:Hydralazine / Q000494:pharmacology / Q000627:therapeutic use*; D006973:Hypertension / Q000188:drug therapy* / Q000503:physiopathology; D009599:Nitroprusside / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011919:Rats, Inbred Strains
D009599:Nitroprusside; D006830:Hydralazine; D000109:Acetylcholine