Graduation Year

2016

Document Type

Thesis

Degree

M.S.B.E.

Degree Name

MS in Biomedical Engineering (M.S.B.E.)

Degree Granting Department

Chemical Engineering

Major Professor

Joseph P. Walton, Ph.D.

Co-Major Professor

Venkat R. Bhethanabotla, Ph.D.

Committee Member

Robert D. Frisina, Ph.D.

Keywords

Bumetanide, Ion Channels, K+ Currents, Micropipette, Patch Clamp

Abstract

Ion channels play a critical role in maintaining homeostasis by moving various ions in and out of cells. The Na+-K+-2Cl- or NKCC1 ion channel is involved in the regulation of Na+, K+, and Cl- across cell membranes, and plays a key role in many forms of cellular physiology. In the cochlea, NKCC1 is involved in endolymph production and maintenance of the endocochlear potential. Our hypothesis is that blocking NKCC1 channels should directly impact auditory sensitivity causing hearing loss. Our lab has also shown that the hormone aldosterone (ALD) can upregulate NKCC1 protein expression in vitro and in vivo. In the present investigation, we use electrophysiology and molecular biology techniques to study the biophysical mechanisms underlying the action of ALD in vitro on NKCC1 in the SH-SY5Y cell line. Our initial protein expression studies using RT-PCR found that proteins specific to NKCC1channels were present in SH-SY5Y neuronal cells. Whole cell currents measured using patch clamp methodology, were used to analyze the effects of various compounds on NKCC1 in the SH-SY5Y cell line. Control data were collected under perfusion of extracellular solution (ECS), then ECS containing 10µM bumetanide was applied, and, finally a washout condition completed the experiment. Similar experiments were conducted using ALD, and we observed an increase in K+ currents when bumetanide as well as when ALD was applied. This is the first report that indicates that ALD can directly regulate K+ channels in SH-SY5Y cells.

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