Research in my laboratory concerns neurotransmitter and hormone-mediated anion (Cl- and HCO3-) secretion in the gastrointestinal system and airway, especially by the epithelium of the intestine and airway and by liver and pancreatic ducts. Of special interest are K+ channels in the basolateral cell membrane of these secretory cells that play a critical role in secretion by maintaining membrane potential as a driving force for anion exit across the apical cell membrane. We use electrophysiological techniques, like transepithelial voltage-clamp and whole-cell and single channel patch-clamp techniques, to characterize membrane ion channels. We also use intracellular fluorescence techniques (e.g., Fura-2) to determine the mechanisms by which neurotransmitters and hormones regulate ion channels via signal transduction pathways. Results of our studies will lead to understanding of normal anion secretion and will help develop remedies for defects in secretion, especially in diseases like secretory diarrhea and cystic fibrosis.

I am also collaborating with Dr. Mark Parker to understand the role of a membrane transport protein encoded by SLC4A11 in endothelial cells of the cornea of the eye. Corneal endothelial cells pump fluid out of the stroma into the aqueous humor to maintain critical corneal transparency. We believe that the SLC4A11 protein is an H+ channel and are using electrophysiological techniques to characterize its properties.