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Vasoconstrictor activity of arginine vasopressin in rat small mesenteric arteries after hindlimb suspension
Author(s) -
Trandafir Cristina Corina,
Kaufman Susan
Publication year - 2007
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.21.6.a950-b
Subject(s) - vasopressin , medicine , vasoconstriction , endocrinology , vascular resistance , hindlimb , mesenteric arteries , myograph , arginine , vasodilation , blood pressure , chemistry , artery , biochemistry , amino acid
One of the factors responsible for orthostatic hypotension after spaceflight is an inability to adequately maintain cardiac afterload. Arginine vasopressin (AVP) increases arterial blood pressure by controlling both blood volume (antidiuresis) and total peripheral resistance (vasoconstriction). Plasma levels of AVP have been recently reported to increase after simulated microgravity. The present study aimed to investigate the vasoconstrictor activity of AVP on peripheral resistance vessels (small mesenteric arteries) in a hindlimb‐unloaded (HU) rat model. Male Long Evans rats were tail‐suspended at 35 degrees for 14 days. Small mesenteric arteries (2 nd order) were isolated and pressurized at 70 mmHg in a pressure myograph. Sensitivity and maximal responses to AVP (10 −12 to 3x10 −8 M) were assessed. There was no difference between HU and Control groups with regard to either EC 50 (HU: 6.8±1.2 x 10 −10 M, n = 8; Control: 7.9±1.7 x 10 −10 M, n = 6) or maximal response to AVP. Contrary to a previous report of hyporesponsiveness to AVP in rat aorta after hindlimb suspension, the activity of this hormone in resistance‐sized mesenteric vessels of male rats is not changed by exposure to simulated microgravity. This research was supported by The Canadian Space Agency.