title: Effects of endothelin receptor antagonist on expression of AT1 and AT2 receptors in the heart of SHR-SP.
abstract: It is already well known that alteration of angiotensin II (Ang II) receptors results in cardiac remodeling in different pathological states, and it is believed that Ang II stimulates the release of endothelin-1 (ET-1). The present study aimed at investigating the interaction between ET-1 and different Ang II receptors in the heart of stroke-prone spontaneously hypertensive rats (SHR-SP). These were treated for 3 months with SB209670, an endothelin-A/endothelin-B dual receptor antagonist, or saline (vehicle) starting from the prehypertensive stage (6 weeks of age). Blood pressure, body weight, heart weight and left ventricular weight were sufficiently decreased after treatment of SHR-SP with SB209670. Ang II type 1 receptor was significantly upregulated in the heart of vehicle-treated SHR-SP compared with the age-matched control, Wistar-Kyoto rat. After endothelin antagonism with SB209670, Ang II type 1 receptor in SHR-SP heart was markedly suppressed. On the other hand, Ang II type 2 receptor was approximately 45% downregulated in the heart of vehicle-treated SHR-SP compared with that of the control, and recovered after endothelin antagonism. The present study demonstrates for the first time the effects of endothelin antagonism on the differential expression and regulation of Ang II receptors in the malignant hypertensive model, SHR-SP, and suggests that the endothelin system may be able to function on the upstream of Ang II signaling.
authors.affiliation: Department of Cardiovascular Medicine, Hokkaido University School of Medicine, Sapporo, Japan.
authors.forename: Subrina
authors.initials: S
authors.lastname: Jesmin
authors.forename: Ichiro
authors.initials: I
authors.lastname: Sakuma
authors.forename: Hiroko
authors.initials: H
authors.lastname: Togashi
authors.forename: Mitsuhiro
authors.initials: M
authors.lastname: Yoshioka
authors.forename: Yuichi
authors.initials: Y
authors.lastname: Hattori
authors.forename: Akira
authors.initials: A
authors.lastname: Kitabatake
authors.forename: Takashi
authors.initials: T
authors.lastname: Miyauchi
mesh_terms: D000804:Angiotensin II / Q000378:metabolism; D000818:Animals; D003331:Coronary Vessels / Q000187:drug effects* / Q000378:metabolism; D004195:Disease Models, Animal; D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1 / Q000378:metabolism; D006973:Hypertension / Q000150:complications / Q000188:drug therapy* / Q000378:metabolism; D007189:Indans / Q000494:pharmacology*; D008297:Male; D009206:Myocardium / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism*; D044139:Receptor, Angiotensin, Type 2 / Q000378:metabolism*; D044022:Receptor, Endothelin A / Q000378:metabolism; D044023:Receptor, Endothelin B / Q000378:metabolism; D015398:Signal Transduction / Q000187:drug effects; D020521:Stroke / Q000209:etiology / Q000378:metabolism
chemical_list: D065130:Endothelin A Receptor Antagonists; D065131:Endothelin B Receptor Antagonists; D019332:Endothelin-1; D007189:Indans; D044140:Receptor, Angiotensin, Type 1; D044139:Receptor, Angiotensin, Type 2; D044022:Receptor, Endothelin A; D044023:Receptor, Endothelin B; 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