Angiotensin II type 1 (AT(1)) receptor blockade enhances the L-NAME-induced vasoconstriction in rat submandibular gland.
The vasoregulatory role of nitric oxide (NO) and angiotensin II type 1 (AT(1)) receptors in the circulation of the submandibular gland (SMG) of rats was studied. The glandular blood flow was determined by means of laser Doppler flowmetry and rubidium isotope technique. The data obtained by these two methods correlated well (r = 0.77; P < 0.01). The AT(1) receptor antagonist candesartan (0.5 mg kg(-1), i.v.) reduced the vascular resistance in the SMG by 37 % (P < 0.05). By contrast, the NO synthase blocker L-NAME (15 mg kg(-1), i.v.) significantly increased vascular resistance in the SMG both in candesartan-treated (P < 0.001) and non-treated (P < 0.001) animals. The increase in resistance was greater (P < 0.05) after previous blockade of AT(1) receptors. These findings suggest that the AT(1) receptors have an important role in the vasoregulation of the SMG in the rat. As a result of AT(1) blockade, NO-dependent tone of glandular vessels may be enhanced significantly.
Vág
J
J
Department of Conservative Dentistry, Semmelweis University, Mikszáth K. tér 5, Budapest 1088, Hungary. vag@konfog.sote.hu
Kerémi
Beáta
B
Hably
Csilla
C
Bartha
J
J
Fazekas
A
A
D057911:Angiotensin Receptor Antagonists; D000818:Animals; D001562:Benzimidazoles / Q000494:pharmacology; D001713:Biphenyl Compounds; D001794:Blood Pressure / Q000187:drug effects; D004791:Enzyme Inhibitors / Q000494:pharmacology*; D006339:Heart Rate / Q000187:drug effects; D017078:Laser-Doppler Flowmetry; D008297:Male; D019331:NG-Nitroarginine Methyl Ester / Q000494:pharmacology*; D019001:Nitric Oxide Synthase / Q000037:antagonists & inhibitors*; D052250:Nitric Oxide Synthase Type III; D051381:Rats; D017208:Rats, Wistar; D044140:Receptor, Angiotensin, Type 1; D012039:Regional Blood Flow / Q000187:drug effects; D012414:Rubidium Radioisotopes; D013363:Submandibular Gland / Q000098:blood supply* / Q000187:drug effects; D013777:Tetrazoles / Q000494:pharmacology; D014661:Vasoconstriction / Q000187:drug effects*
D057911:Angiotensin Receptor Antagonists; D001562:Benzimidazoles; D001713:Biphenyl Compounds; D004791:Enzyme Inhibitors; D044140:Receptor, Angiotensin, Type 1; D012414:Rubidium Radioisotopes; D013777:Tetrazoles; D019001:Nitric Oxide Synthase; D052250:Nitric Oxide Synthase Type III; C496316:Nos3 protein, rat; C081643:candesartan; D019331:NG-Nitroarginine Methyl Ester