ILEOCECAL SPHINCTER REFLEX AND SPHINCTERIC PROPERTIES

Project: Research project

Project Details

Description

The long-term goal of this project is to define the physiologic response of
the ileocecal sphincter (ICS) to feeding and to determine the contribution
of various components of the anatomic ICS to these physiologic responses.
These studies will contribute towards an understanding of the integrative
role, if any, of the ICS between ileal and colonic function. The project
will consist of in vivo studies on the anesthetized cat in which
intraluminal pressures and serosal myoelectric activity are recorded
simultaneously and in vitro muscle strip studies which will also allow the
simultaneous recording of extracellular electrical activity and contractile
activity. Discrepancy exists between in vivo responses seen at the ICS to
transmural stimulation and to intravenous neurohumoral agents and the in
vitro response of ICS muscle strips to these same stimuli. Experiments
will be designed to determine the reason for such discrepancy; to determine
which specific parts of the anatomic ileo-cecal-colonic apparatus
contributes to the physiologic and in vivo ICS responses; and to determine
whether in vivo responses depend on an integrated response of the ileum,
ICS and colon. The pathway and neurotransmitters mediating the ICS reflex
responses to ileal and colonic balloon distension will be investigated
using neurotoxin, myomectomy techniques and pharmacologic antagonists of
classical neurotransmitters. In addition, the mediator of the stimulus
relaxation in vitro to transmural electrical stimulation will be
investigated. Those agents already demonstrated to induce ICS relaxation
will be studied in addition to VIP, the major candidate for the
neurotransmitter in non-cholinergic, non-adrenergic nerves. This will be
examined by means of tachyphylaxis. Peptides which are putative
neurotransmitters will be investigated in vivo an in vitro for their action
at the ICS and for their possible role in mediating the gastro-ileocolonic
response.
StatusFinished
Effective start/end date1/1/901/1/90

Funding

  • NATIONAL INSTITUTE OF DIABETES AND DIGESTIVE AND KIDNEY DISEASES