title: Angiotensin II and vasopressin are involved in the defense system against anaphylactic hypotension in anesthetized rats.
abstract: Anaphylactic shock is sometimes life-threatening, but the defense system against this circulatory failure was not fully understood. Ameliorating roles of angiotensin (ANG) II and vasopressin in anaphylactic hypotension were investigated in anesthetized ovalbumin-sensitized Sprague-Dawley rats. The sensitized rats were randomly allocated to the following pretreatment groups (n=7/group): (1) control (non-pretreatment), (2) ANG II synthesis inhibitor captopril, (3) ANG II receptor antagonist losartan, and (4) V1a vasopressin receptor antagonist. Anaphylactic shock was induced by an intravenous injection of the antigen. The systemic arterial pressure (SAP), central venous pressure (CVP), portal venous pressure (PVP) and portal venous blood flow (PBF) were measured, and splanchnic vascular resistance (Rspl: (SAP-PVP)/PBF) was determined. In the control group, SAP markedly decreased, followed by a gradual recovery toward baseline. Rspl transiently decreased immediately after antigen, and then increased 1.5-fold at 15 min and thereafter. The pretreatment with either losartan, captopril or V1a receptor antagonist augmented the initial fall of SAP and attenuated the SAP recovery along with augmentation of the late increase in Rspl. The 2-h survival rate was significantly smaller in either pretreatment group than in the control group (100%). Plasma levels of ANG II and vasopressin increased to 3.8- and 9.8-fold, respectively, at 30 min after antigen in the control group, whereas captopril pretreatment inhibited the increase in ANG II. In conclusion, inhibition of ANG II or vasopressin exacerbates anaphylaxis-induced hypotension in anesthetized rats.
authors.affiliation: Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan; Department of Colorectal Surgery, The Fourth Affiliated Hospital of China Medical University, Shenyang 110032, China.
authors.forename: Mofei
authors.initials: M
authors.lastname: Wang
authors.affiliation: Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan. Electronic address: shibamo@kanazawa-med.ac.jp.
authors.forename: Toshishige
authors.initials: T
authors.lastname: Shibamoto
authors.affiliation: Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan.
authors.forename: Yuhichi
authors.initials: Y
authors.lastname: Kuda
authors.affiliation: Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan; Department of Hematology, The Fourth Affiliated Hospital of China Medical University, Shenyang 110032, China.
authors.forename: Lingling
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan.
authors.forename: Mamoru
authors.initials: M
authors.lastname: Tanida
authors.affiliation: Department of Physiology II, Kanazawa Medical University, Uchinada 920-0293, Japan.
authors.forename: Yasutaka
authors.initials: Y
authors.lastname: Kurata
mesh_terms: D000707:Anaphylaxis / Q000097:blood* / Q000503:physiopathology*; D000758:Anesthesia; D000804:Angiotensin II / Q000097:blood*; D000818:Animals; D001794:Blood Pressure / Q000187:drug effects; D002216:Captopril / Q000494:pharmacology; D006439:Hemodynamics / Q000187:drug effects; D008297:Male; D051381:Rats; D017207:Rats, Sprague-Dawley; D014667:Vasopressins / Q000037:antagonists & inhibitors / Q000097:blood*
chemical_list: D014667:Vasopressins; D000804:Angiotensin II; D002216:Captopril
keywords: ANG II; Anaphylactic shock; Captopril; Losartan; Ovalbumin-sensitized rats; Splanchnic vascular resistance