Date of Graduation
Doctor of Philosophy in Kinesiology (PhD)
Health, Human Performance and Recreation
Heidi A. Kluess
Dean R. Gorman
Second Committee Member
David L. Kreider
Third Committee Member
Sean W. Mulvenon
Fourth Committee Member
Charles E. Riggs
Biological sciences; Arterioles; Dipeptidyl peptidase; Estrogens; Neuropeptide Y; Skeletal muscle
The purpose of this study was to determine the effects of chronic estrogen supplementation on NPY neurotransmission in gastrocnemius first-order arterioles (G1A) of adult female rats. Female rats (4 mo; n = 30) were ovariectomized (OVX) with a subset (n = 15) receiving an estrogen pellet (OVE; 17β-estradiol (4μg / day)). Following conclusion of the treatment phase (8 weeks), red G1A were excised, placed in a physiological saline solution (PSS) bath, and cannulated with micropipettes connected to albumin reservoirs. A sampling port was placed immediately below the vessel to assess NPY overflow. The contralateral red G1A was homogenized in PSS for dipeptidyl peptidase IV (DPPIV) assay. NPY-mediated vasoconstriction via a Y1-agonist, [Leu31Pro34]NPY, decreased vessel diameter 44.54 ± 3.95% as compared to baseline; however, there were no group differences in EC50 (OVE: -8.97 ± 0.36; OVX: -8.72 ± 0.20 log M [Leu31Pro34]NPY) or slope (OVE: -1.37 ± 0.38; OVX: -1.64 ± 0.31 % 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). Estrogen status did not affect DPPIV activity. These data suggest that NPY can induce a moderate decrease in vessel diameter in skeletal muscle G1A, and DPPIV is active in mitigating NPY overflow in young adult female rats. Chronic estrogen supplementation did not influence NPY vasoconstriction, overflow, or its enzymatic breakdown in skeletal muscle G1A.
Evanson, Kirk Wendell, "The Effects of Ovariecotomy on Neuropeptide Y Neurotransmission in Skeletal Muscle Arterioles" (2011). Theses and Dissertations. 205.