title: A reduction in the amount and anti-contractile effect of periadventitial mesenteric adipose tissue precedes hypertension development in spontaneously hypertensive rats.
abstract: The aim of this study was to determine whether alterations in periadventitial adipose tissue and its anti-contractile effect precede hypertension development. We used 4-week-old male Wistar Kyoto (WKY) and spontaneously hypertensive rats (SHR), which were pre-hypertensive. Vascular function was studied in the perfused mesenteric bed (MB, 1.5 mL/min). MB weight was lower in SHR (8.0 +/- 0.3 mg/g body weight) than in WKY (9.0 +/- 0.3 mg/g body weight) rats. Concentration-response curves to KCI (6 to 75 mmol/L) and to acetylcholine (10(-9) to 10(-5) mol/L) were similar between groups. Contractile responses to serotonin (10(-9) to 10(-5) mol/L) were significantly higher in SHR compared to WKY. 4-Aminopyridine (4-AP, 2 mmol/L), a blocker of Kv channels, induced a similar increase in perfusion pressure in both strains. However, 4-AP (2 mmol/L) significantly increased the contractile response to serotonin (10(-9) to 10(-5) mol/L) only in WKY. The anti-contractile effect of fat was confirmed by a comparison of (+) fat and (-) fat mesenteric arteries, which revealed that 4-AP significantly enhanced contractions only in (+) fat rings from WKY. These results show that alterations in visceral periadventitial fat mass and function in SHR precede hypertension, suggesting a constitutive mechanism independent of age and the hypertensive state.
authors.affiliation: Pluridisciplinary Institute, Complutense University, Madrid, Spain.
authors.forename: Beatriz
authors.initials: B
authors.lastname: Gálvez-Prieto
authors.forename: Galyna
authors.initials: G
authors.lastname: Dubrovska
authors.forename: M Victoria
authors.initials: MV
authors.lastname: Cano
authors.forename: Mercedes
authors.initials: M
authors.lastname: Delgado
authors.forename: Isabel
authors.initials: I
authors.lastname: Aranguez
authors.forename: M Carmen
authors.initials: MC
authors.lastname: González
authors.forename: Mariano
authors.initials: M
authors.lastname: Ruiz-Gayo
authors.forename: Maik
authors.initials: M
authors.lastname: Gollasch
authors.forename: Maria S
authors.initials: MS
authors.lastname: Fernández-Alfonso
mesh_terms: D015761:4-Aminopyridine / Q000494:pharmacology; D000273:Adipose Tissue / Q000503:physiopathology*; D000818:Animals; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D008638:Mesenteric Arteries / Q000503:physiopathology*; D009569:Nitric Oxide / Q000502:physiology; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011918:Rats, Inbred SHR; D011921:Rats, Inbred WKY; D013152:Splanchnic Circulation; D014661:Vasoconstriction / Q000502:physiology*
chemical_list: D009569:Nitric Oxide; D015761:4-Aminopyridine; D009638:Norepinephrine