Date Approved

4-27-2017

Graduate Degree Type

Thesis

Degree Name

Biomedical Sciences (M.H.S.)

Degree Program

Biomedical Sciences

First Advisor

Frank Sylvester

Second Advisor

Debra Burg

Third Advisor

Douglas Graham

Academic Year

2016/2017

Abstract

β-methylphenylethylamine (BMPEA) was first synthesized in the 1930’s as a potential stimulant and amphetamine replacement. It was expected to act as an indirect sympathomimetic agent that binds to peripheral α- and β- adrenergic receptors to control vascular responses in peripheral sites. The effects of BMPEA were never studied in humans, but due to its structural similarity to amphetamines as well as the effects noticed in animal studies in the 1920’s and 1930’s, BMPEA was assumed to work as a vasoconstrictor. In the current study, porcine mesenteric arteries were used as a model following confirmation of arterial viability with the known constrictor, KCl, and the known dilator, nitroprusside. Using an isolated vascular ring protocol, arteries were exposed to increasing concentrations (1x10-7M to 1x10-3M) of BMPEA to determine changes in vascular reactivity. The results were compared to constriction in response to the known α-adrenergic agonist phenylephrine (1x10-7M to 1x10-4M), and to dilation in response to the known β- adrenergic agonist isoproterenol (1x10-7M to 1x10-4M). No significant change in arterial tension was noted when BMPEA was added as a potential constrictor, or when it was added as a potential dilator after pre-constriction with KCl. Phenylephrine induced a significant increase in tension, serving as a positive control for α-adrenergic-mediated vasoconstriction. However, isoproterenol did not show a decrease in tension with administration of increasing concentrations as expected. The presence of an α-adrenergic receptor-mediated response in the tested porcine vasculature was confirmed by incubation with 1x10-5M of the α-adrenergic antagonist phentolamine. This was effective in blocking the phenylephrine-induced constriction. BMPEA caused no change in tension when administered following phentolamine incubation. Propranolol (1x10-5M) was used to block β-adrenergic receptors with the addition of BMPEA and isoproterenol. BMPEA showed no change in arterial tension for any of these experiments, and it was concluded that it does not act as a vasoactive agent to constrict or dilate arteries in porcine mesenteric vasculature. Further studies are needed to determine whether BMPEA elicits a vascular response in other organ systems, or if it indeed demonstrates no vascular effect in this species.

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