James J. Galligan, PhD
Neuroscience Program Director
Professor, Pharmacology and Toxicology
Ph.D., 1983, University of Arizona
My research interests are focused on neural control of gastrointestinal motility and blood flow. Gastrointestinal problems are very common and are among the most frequently cited reasons a patient will see their physician in the United States. Although gastrointestinal disorders are an important health issue very little is known about neural control of gut function.
The functions of the gastrointestinal tract are largely controlled by the enteric nervous system, the division of the autonomic nervous system that resides in the gut wall. The enteric nervous system can perform its diverse functions independently of input from the central nervous system.
Our research is focused on identifying the unique mechanisms of neurotransmission that allow the enteric nervous system to control gut function. Electrophysiological methods are the principal techniques that are used to address this research problem. We are using electrophysiological methods to record from single enteric nerves in vitro in acutely isolated preparations of guinea pig small intestine. This preparation is useful as most neural connections present in the intact intestine are preserved and the endogenous neural circuits that control gastrointestinal function can be studied.
We are also using patch clamp methods to record from enteric neurons maintained in primary tissue culture. Using patch clamp methods, we can study in great detail the ionic mechanisms of neurotransmission, the kinetics of neurotransmitter action and the intracellular signal transduction mechanisms mediating neuron to neuron communication. In addition, the behavior of single ion channels in membrane patches of nerves cells using the patch clamp method can be examined.
We are using video-based digital microscopy to study neuronal control of the diameter of small blood vessels in the intestinal wall. These methods allow combined electrophysiological and pharmacological analysis of the nerves and neural mechanisms that regulate gastrointestinal blood flow.
In addition to studying neural control of gut function, there is also a significant research effort directed at understanding changes in neural control of blood vessels in an experimental model of hypertension. Several techniques are used to assess neural control of the diameter of small blood vessels in the intestinal wall and also global nerve activity associated with cardiovascular tissues. These methods include nerve recordings in anesthetized animals, electrophysiological techniques and digital imaging methods to measure nerve stimulation induced changes in blood vessel diameter. These methods allow combined electrophysiological and pharmacological analysis of the nerves and neural mechanisms that blood pressure.
Please feel free to contact me if you have any questions about my research.