Endothelin receptor antagonists reduce the pressor effects of angiotensin II into the periaqueductal gray area of rats.
Injection of ANGII (0.01, 0.1 and 1 nmol/rat) into the periaqueductal gray (PAG) area significantly (P<0.01) increased, in a dose-dependent manner, the mean arterial blood pressure (MAP). The increases in blood pressure induced by ANGII (1 nmol; 37 +/- 4 mmHg, n=5) were greatly reduced (>85%) by pre-administration of the ET(A) receptor antagonist FR139317 (5 nmol/rat) to the PAG area, but were unaffected by the ET(B) receptor antagonist BQ-788 (5 nmol/rat). SB209670, non-selective ET(A)/ET(B) receptor antagonist, also reduced the effect induced by ANGII. These results suggest that endogenous endothelin-1, via an action on ET(A) receptors, may contribute to the pressor effects of ANGII within the PAG area of rats.
D'Amico
M
M
Institute of Pharmacology and Toxicology, Faculty of Medicine and Surgery, 2nd University of Naples, Italy.
Di Filippo
C
C
Filippelli
A
A
Rossi
F
F
D000804:Angiotensin II / Q000494:pharmacology*; D000818:Animals; D001381:Azepines / Q000494:pharmacology; D001794:Blood Pressure / Q000187:drug effects*; D004305:Dose-Response Relationship, Drug; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1 / Q000502:physiology; D007189:Indans / Q000494:pharmacology; D007211:Indoles / Q000494:pharmacology; D008297:Male; D009842:Oligopeptides / Q000494:pharmacology; D010487:Periaqueductal Gray / Q000187:drug effects*; D010880:Piperidines / Q000494:pharmacology; D051381:Rats; D017207:Rats, Sprague-Dawley; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin / Q000502:physiology
D001381:Azepines; D065128:Endothelin Receptor Antagonists; D019332:Endothelin-1; D007189:Indans; D007211:Indoles; D009842:Oligopeptides; D010880:Piperidines; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; D017466:Receptors, Endothelin; C087551:1H-Indene-2-carboxylic acid, 1-(1,3-benzodioxol-5-yl)-3-(2- (carboxymethoxy)-4-methoxyphenyl)-2,3-dihydro-5-propoxy-, (1S,2R,3S)-; D000804:Angiotensin II; C079574:FR 139317; C086539:BQ 788