title: Colony social stress differentially alters blood pressure and resistance-sized mesenteric artery reactivity in SHR/y and WKY male rats.
abstract: Increased sympathetic nervous system (SNS) activity, testosterone, and spontaneously hypertensive rat Y chromosome (SHR Yc) play a role in a genetic model of hypertension. Male rats with the SHR Yc and Wistar-Kyoto (WKY) autosomes (denoted SHR/y) exhibit these characteristics when compared to rats with the WKY Yc and WKY autosomes (denoted WKY). We hypothesized that chronic social stress will increase blood pressure and SNS activity more in SHR/y males compared to WKY males, resulting in increased myogenic reactivity along with decreased vasoconstriction of small mesenteric arteries. SHR/y and WKY males were housed in strain- specific colonies (10 males with 10 females) or as controls (10 males). Systolic blood pressure (SBP) and blood samples were collected prior to termination. Second-order mesenteric arteries were studied using a pressure arteriograph in which myogenic reactivity and phenylephrine (PE) responsiveness were measured. SHR/y colony SBP, and circulating norepinephrine and testosterone concentrations were elevated compared to control and WKY colony males (p < 0.05). Mesenteric artery myogenic reactivity was increased in SHR/y colony males (p < 0.001). Mesenteric arteries from SHR/y colony males exhibited a significant decrease in PE-induced constriction. Colony social stress elevated both SNS activity and testosterone level which may be responsible for the increased mesenteric artery myogenic reactivity, and SBP as noted in SHR/y males.
authors.affiliation: Department of Biology, The University of Akron, Akron, OH 44325-3908, USA.
authors.forename: Jonathan D
authors.initials: JD
authors.lastname: Toot
authors.forename: John J
authors.initials: JJ
authors.lastname: Reho
authors.forename: Jacqueline
authors.initials: J
authors.lastname: Novak
authors.forename: Gail
authors.initials: G
authors.lastname: Dunphy
authors.forename: Daniel L
authors.initials: DL
authors.lastname: Ely
authors.forename: Rolando J
authors.initials: RJ
authors.lastname: Ramirez
mesh_terms: D000818:Animals; D001794:Blood Pressure / Q000187:drug effects*; D003441:Crowding; D006799:Housing, Animal; D008297:Male; D008638:Mesenteric Arteries / Q000502:physiology; D009638:Norepinephrine / Q000097:blood; D010656:Phenylephrine / Q000494:pharmacology; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013315:Stress, Psychological; D013739:Testosterone / Q000097:blood; D014661:Vasoconstriction / Q000187:drug effects*; D014998:Y Chromosome
chemical_list: D010656:Phenylephrine; D013739:Testosterone; D009638:Norepinephrine