title: Influence of estradiol supplementation on neuropeptide Y neurotransmission in skeletal muscle arterioles of F344 rats.
abstract: The effects of estradiol on neuropeptide Y (NPY) neurotransmission in skeletal muscle resistance vessels have not been described. The purpose of this study was to determine the effects of long-term estradiol supplementation on NPY overflow, degradation, and vasoconstriction in gastrocnemius first-order arterioles of adult female rats. Female rats (4 mo; n = 34) were ovariectomized (OVX) with a subset (n = 17) receiving an estradiol pellet (OVE; 17β-estradiol, 4 μg/day). After conclusion of the treatment phase (8 wk), arterioles were excised, placed in a physiological saline solution (PSS) bath, and cannulated with micropipettes connected to albumin reservoirs. NPY-mediated vasoconstriction via a Y(1)-agonist [Leu31Pro34]NPY decreased vessel diameter 44.54 ± 3.95% compared with baseline; however, there were no group differences in EC(50) (OVE: -8.75 ± 0.18; OVX: -8.63 ± 0.10 log M [Leu31Pro34]NPY) or slope (OVE: -1.11 ± 0.25; OVX: -1.65 ± 0.34% baseline/log M [Leu31Pro34]NPY). NPY did not potentiate norepinephrine-mediated vasoconstriction. NPY overflow experienced a slight increase following field stimulation and significantly increased (P < 0.05) over control conditions in the presence of a DPPIV inhibitor (diprotin A). Estradiol status did not affect DPPIV activity. These data suggest that NPY can induce a moderate decrease in vessel diameter in skeletal muscle first-order arterioles, and DPPIV is active in mitigating NPY overflow in young adult female rats. Long-term estradiol supplementation did not influence NPY vasoconstriction, overflow, or its enzymatic breakdown in skeletal muscle first-order arterioles.
authors: Department of Health, Human Performance and Recreation, University of Arkansas, Fayetteville, USA.
authors: Kirk W
authors: KW
authors: Evanson
authors: Audrey J
authors: AJ
authors: Stone
authors: Enoch
authors: E
authors: Samraj
authors: Tyler
authors: T
authors: Benson
authors: Rhonda
authors: R
authors: Prisby
authors: Heidi A
authors: HA
authors: Kluess
mesh_terms: D000818:Animals; D001160:Arterioles / Q000294:innervation* / Q000502:physiology*; D004343:Drug Implants; D004958:Estradiol / Q000008:administration & dosage / Q000494:pharmacology*; D005260:Female; D005786:Gene Expression Regulation / Q000187:drug effects / Q000502:physiology; D018482:Muscle, Skeletal / Q000098:blood supply*; D009478:Neuropeptide Y / Q000235:genetics / Q000378:metabolism*; D010052:Ovariectomy; D051381:Rats; D009435:Synaptic Transmission / Q000187:drug effects*
chemical_list: D004343:Drug Implants; D009478:Neuropeptide Y; D004958:Estradiol