Sang Don Koh, Ph.D.

Title:  Professor

Contact Information

Mail Stop: 352
Phone: 775-784-1924
e-mail: skoh@medicine.nevada.edu

Research Interests

I achieved my Ph.D. under Prof. Kee Soon Kim at Hanyang University, Korea. I started patch clamp experiments on gastrointestinal smooth muscle cells at Kyushu University, Japan, under the supervision of Prof. Kuriyama. I have always had a lot of interest in the spontaneous electrical rhythmicity of the gastrointestinal tract. I met Dr. Kenton M. Sanders in 1991. I then moved to Dr. Sanders lab at the University of Nevada, Reno in 1992.

The research in our laboratory is aimed at investigating the electrical activity of colonic myocytes and ICC. In the laboratory the patch clamp and Ca2+ imaging techniques are utilized to study cultured or freshly dispersed ICC? or gastrointestinal myocytes.

The main aims of the study are to understand: 1) the mechanisms of spontaneous rhythmicity in ICC, 2) the intracellular signaling pathways by enteric neurotransmitters, and 3) the physiological meaning of intracellular Ca2+ puff and it regulation.

I have worked mainly on the research of the properties on the delayed rectifier K+ channels, KATP, Ca2+-activted small conductance K+ channels, A-type channels and inwardly rectifying K+ channels and their regulations in colonic myocytes with the collaboration of Dr. James L. Kenyon. Dr. Burton Horowitz has also cloned and expressed many potassium channels in oocytes and mammalian cell line in order to compare expressed and native channel characteristics. Recently I have been studying the role of Ca2+/calmodulin kinase and K+ channel regulation with Dr. Brian A. Perrino.

In 1996 Dr. Sean M. Ward developed an ICC culturing technique and I recorded spontaneous electrical activity from cultured ICC?. This will give us a better insight into the pacemaker role of ICC. ICC can also be controlled by enteric neuronal stimulation and therefore it will be a very important tool in solving the gastrointestinal response to this stimulation.

I always believe that God must create the unique channels in gastrointestinal tract that are not even found in brain. I am always trying to find God's creations.

Search For Dr. Koh's Publications In PubMed

Selected Publications

Beckett EA, McCloskey C, O'Kane N, Sanders KM, Koh SD. Effects of female steroid hormones on A-type K+ currents in murine colon. J Physiol 573:453-468 (2006)

Sanders KM, Koh SD, Ward SM. Interstitial cells of cajal as pacemakers in the gastrointestinal tract. Annu Rev Physiol 68:307-343 (2006)

Sanders KM, Koh SD. Two-pore-domain potassium channels in smooth muscles: new components of myogenic regulation. J Physiol.570:37-43 (2006)

Cho SY, Beckett EA, Baker SA, Han I, Park KJ, Monaghan K, Ward SM, Sanders KM, Koh SD. A pH-sensitive potassium conductance (TASK) and its function in the murine gastrointestinal tract. J Physiol 565:243-59 (2005)

Park KJ, Baker SA, Cho SY, Sanders KM, Koh SD. Sulfur-containing amino acids block stretch-dependent K+ channels and nitrergic responses in the murine colon. Br J Pharmacol 144:1126-1137 (2005)

Takeda Y, Ward SM, Sanders KM, Koh SD. Effects of the gap junction blocker glycyrrhetinic acid on gastrointestinal smooth muscle cells. Am J Physiol Gastrointest Liver Physiol 288(4):G832-841 (2005)

Sergeant GP, Ohya S, Reihill JA, Perrino BA, Amberg GC, Imaizumi Y,
Horowitz B, Sanders KM, Koh SD. Regulation of Kv4.3 currents by Ca2+/calmodulin-dependent protein kinase II. Am J Physiol Cell Physiol. 288:C304-313 (2005)

Callaghan B, Koh SD, Keef KD. Muscarinic M2 receptor stimulation of Cav1.2b requires phosphatidylinositol 3-kinase, protein kinase C, and c-Src. Circ Res 94:626-633 (2004)

Koh SD, Ward SM, Ordog T, Sanders KM, Horowitz B. Conductances responsible for slow wave generation and propagation in interstitial cells of Cajal. Curr Opin Pharmacol 3:579-582 (2003)

Baker SA, Mutafova-Yambolieva V, Monaghan K, Horowitz B, Sanders KM, Koh SD. Mechanism of active repolarization of inhibitory junction potential in murine colon. Am J Physiol Gastrointest Liver Physiol 285:G813-821 (2003)

Koh SD, Jun JY, Kim TW, Sanders KM. A Ca(2+)-inhibited non-selective cation conductance contributes to pacemaker currents in mouse interstitial cell of Cajal. J Physiol 540:803-814 (2002)

Koh SD, Monaghan K, Sergeant GP, Ro S, Walker RL, Sanders KM, Horowitz B. TREK-1 regulation by nitric oxide and cGMP-dependent protein kinase. An
essential role in smooth muscle inhibitory neurotransmission. J Biol Chem. 2001 Nov 23;276(47):44338-46 (2001)

Kong ID, Koh SD, Bayguinov O and Sanders KM: Small conductance Ca2+-activated K+ channels are regulated by Ca2+-calmodulin-dependent protein kinase II in murine colonic myocytes. J. Physiol. (London) 524:331-337, 2000

Kong, I.D., Koh, S.D. and Sanders,K.M. Purinergic activation of spontaneous outward currents in guinea-pig taenia colonic myocytes. Am. J. Physiol (cell) 278: C352-C362, 2000.

Koh, S.D., Perrino, B.A., Hatton, W.J., Kenyon, J.L. and Sanders, K.M. Novel regulation of the A-type current in murine proximal colon by calcium/calmodulin-dependent protein kinase II. J. Physiol. (London) 517:75-84, 1999.

Koh, S.D., K.M. Sanders, and S.M. Ward. Spontaneous electrical rhythmicity in cultured interstitial cells of Cajal from the murine small intestine. J.Physiol.(Lond.) 513: 203-213, 1998.

Koh, S.D., K.K. Bradley, M.G. Rae, K.D. Keef, B. Horowitz, and K.M. Sanders. Basal activation of ATP-sensitive potassium channels in murine colonic smooth muscle cell. Biophys.J. 75: 1793-1800, 1998.

S.D. Koh, G.M. Dick, and K.M. Sanders. Small conductance Ca2+-activated K+-channels activated by ATP in murine colonic smooth muscle. Am. J. Physiol. (Cell) 273: C2010-C2021, 1997.