Research
Interests
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.
Selected
Publications
Search all publications in the NCBI Journal Database
Xu H, Fink GD, Galligan JJ. Increased sympathetic venoconstriction and reactivity to norepinephrine in mesenteric veins in anesthetized DOCA-salt hypertensive rats. Am J Physiol 293: H160-168, 2007.
Park J, Galligan JJ, Fink GD, Swain GM. Differences in sympathetic neuroeffector transmission to mesenteric arteries and veins as probed by in vitro continuous amperometry and video imaging. J Physiol 584: 819-834, 2007.
Ren J, Galligan JJ. A calcium-activated potassium conductance is coupled to P2X receptors in myenteric neurons of guinea pig ileum. Neurogastroentrol Motil 19: 912-22, 2007.
|
James
J. Galligan 