The long term goals of this work are to understand the function of submucous plexus neurons throughout the gastrointestinal (GI) tract. All submucous plexus neurons project to the intestinal mucosa or to each other; thus they may play a major role in controlling or modulating fluid and electrolyte transport in the intestine. Intracellular recordings of membrane voltage and membrane current, using single-electrode voltage clamp techniques, will be obtained from submucous neurons of the guinea-pig small intestine to elucidate the mechanisms of actions of neuropeptides and other putative transmitter substances on the postsynaptic membrane. Patterns of neuronal circuitry will be investigated by selective disruption of pathways to the submucous plexus by carrying our extrinsic denervations, myectomies, and myotomies in combination with electrophysiological studies of the alterations in synaptic input to the lesioned plexus preparation. Mechanisms of synaptic transmission in submucous neurons of the descending colon will be studied in order to investigate the role these neurons may play in the region of the GI tract which is the major site of net fluid and electrolyte absorption. Dysfunction of the neurons of the submucous plexus may be involved with several pathophysiological states, such as as carcinoid syndrome, dumping syndrome and diabetic diarrhea. Knowledge of the functions of these neurons should provide insight into mechanisms underlying these disease states and, potentially, insight into therapeutic means of their control.

Agency
National Institute of Health (NIH)
Institute
National Institute of Neurological Disorders and Stroke (NINDS)
Type
Research Project (R01)
Project #
1R01NS025996-01
Application #
3411591
Study Section
General Medicine A Subcommittee 2 (GMA)
Project Start
1988-04-01
Project End
1991-03-31
Budget Start
1988-04-01
Budget End
1989-03-31
Support Year
1
Fiscal Year
1988
Total Cost
Indirect Cost
Name
Oregon Health and Science University
Department
Type
Overall Medical
DUNS #
009584210
City
Portland
State
OR
Country
United States
Zip Code
97239
Vanner, S; Evans, R J; Matsumoto, S G et al. (1993) Potassium currents and their modulation by muscarine and substance P in neuronal cultures from adult guinea pig celiac ganglia. J Neurophysiol 69:1632-44
Evans, R J; Surprenant, A (1993) Effects of phospholipase A2 inhibitors on coupling of alpha 2-adrenoceptors to inwardly rectifying potassium currents in guinea-pig submucosal neurones. Br J Pharmacol 110:591-6
Shen, K Z; Surprenant, A (1993) Somatostatin-mediated inhibitory postsynaptic potential in sympathetically denervated guinea-pig submucosal neurones. J Physiol 470:619-35
Vanner, S; Jiang, M M; Surprenant, A (1993) Mucosal stimulation evokes vasodilation in submucosal arterioles by neuronal and nonneuronal mechanisms. Am J Physiol 264:G202-12
Shen, K Z; Surprenant, A (1993) Common ionic mechanisms of excitation by substance P and other transmitters in guinea-pig submucosal neurones. J Physiol 462:483-501
Jiang, M M; Kirchgessner, A; Gershon, M D et al. (1993) Cholera toxin-sensitive neurons in guinea pig submucosal plexus. Am J Physiol 264:G86-94
Shen, K Z; North, R A; Surprenant, A (1992) Potassium channels opened by noradrenaline and other transmitters in excised membrane patches of guinea-pig submucosal neurones. J Physiol 445:581-99
Evans, R J; Surprenant, A (1992) Vasoconstriction of guinea-pig submucosal arterioles following sympathetic nerve stimulation is mediated by the release of ATP. Br J Pharmacol 106:242-9
Stack, J; Surprenant, A (1991) Dopamine actions on calcium currents, potassium currents and hormone release in rat melanotrophs. J Physiol 439:37-58
Barajas-Lopez, C; Surprenant, A; North, R A (1991) Adenosine A1 and A2 receptors mediate presynaptic inhibition and postsynaptic excitation in guinea pig submucosal neurons. J Pharmacol Exp Ther 258:490-5

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