Associate Professor

Email: dmkendig@loyola.edu
Phone: 410-617- 5239
Fax: 410-617-5682

Office

Donnelly Science 278
Department of Biology
Loyola University Maryland
4501 North Charles Street
Baltimore, MD 21210-2699

Biography

The gastrointestinal (GI) system is responsible for the digestion of food, absorption of nutrients, and removal of wastes from the body. One of the main ways the GI system accomplishes these tasks is through patterns of muscle contraction and relaxation called GI motility. Nutrients within food can cause or change the motility patterns of the GI system. One of the main goals of the Kendig lab is to understand the mechanisms by which nutrients are able to initiate or modify GI motility. There are multiple motility patterns within the GI tract: including propulsive motility (pushes chyme towards the rectum) and mixing motility patterns (helps with digestion and absorption). Through the use of video recording, computer analysis, and spatiotemporal map generation we can measure the effects of specific nutrients on these natural motility patterns in different regions of the GI tract (specifically the stomach, small intestine, and colon).

Along with measuring the motility patterns of the GI system, the Kendig lab also studies the changes in the ability of GI smooth muscle (which lines the walls of the intestines and stomach) to contract and relax. We also study the intracellular signaling pathways involved in these processes. This allows us to examine the effects of nutrients at both the tissue (muscle contractility) and organ (motility patterns) levels. We hypothesize that nutrients in the lumen of the gut activate receptors in the mucosal layer of the gut wall, which then communicate with the smooth muscle through the enteric nervous system within the intestinal wall. One goal is to determine the receptors activated by specific nutrients (e.g. amino acids or short chain fatty acids) and the chemical mediators used to signal the enteric nervous system downstream of receptor activation. The techniques used to measure muscle contractility and motility patterns can also be applied to other smooth muscle lined organs such as the urinary bladder or blood vessels.

Publications

• Mahavadi S, Nalli AD, Wang H, Kendig DM, Crowe MS, Lyall V, Grider JR, and Murthy KS. Regulation of gastric smooth muscle contraction via Ca2+-dependent and Ca2+-independent actin polymerization. PLoS One. 13(12): e0209359, 2018. PMCID: PMC6301582
• Nalli AD, Bhattacharya S, Wang H, Kendig DM, Grider JR, and Murthy KS. Augmentation of cGMP/PKG pathway and colonic motility by hydrogen sulfide. American Journal of Physiology: Gastrointestinal and Liver Physiology 313(4): G330-341, 2017. PMID: 28705807
  
• Kendig DM, Ets HK, and Moreland RS. Effect of type II diabetes on male rat bladder contractility. Am J Physiol Renal Physiol 310(9): F909-22, 2016. PMID: 26823284
  
• Kendig DM, Hurst N, and Grider JR. Spatiotemporal mapping of motility in ex vivo preparations of the intestines. [online only video article] J Vis Exp (107): 2016. PMID: 26863156
  
• Kendig DM, Grider JR. Serotonin and colonic motility. [Review] Neurogastroenterol Motil 27(7): 899-905, 2015. PMID: 26095115
• Liu M, Shen S, Kendig DM, Mahavadi S, Murthy KS, Grider JR, and Qiao LY. Inhibition of N-methyl-d-aspartate receptor reduces bladder hypertrophy and improves bladder functionality in cyclophosphamide-induced cystitis. J Urol 193(5): 1676-83, 2015. PMID: 25572034
• Anderson CD, Kendig DM, Al-Qudah M, Mahavadi S, Murthy KS, and Grider JR. Role of various kinases in muscarinic M3 receptor-mediated contraction of longitudinal muscle of rat colon. J Smooth Muscle Res 50: 103-119, 2014. PMID: 25891767
  
• Kendig DM, Hurst N, Bradley ZL, Mahavadi S, Kuemmerle JF, Lyall V, DeSimone J, Murthy KS and Grider JR. Activation of the umami taste receptor (T1R1/T1R3) initiates the peristaltic reflex and pellet propulsion in the distal colon. Am J Physiol Gastrointest Liver Physiol 307(11): G1100-7, 2014. PMID: 25324508
• Hurst NR, Kendig DM, Murthy KS, and Grider JR. The short chain fatty acids, butyrate and propionate, have differential effects on the motility of the guinea pig colon. Neurogastroenterol Motil 26(11): 1586-96, 2014. PMID: 25223619

Area of Specialization

• Gastrointestinal Physiology and Nutrition