Patients with Digestive Diseases Gain Hope for Selective Therapies by Targeting Specific Neurotransmitter
Recently, Penn State College of Medicine researchers did some studies regarding neuroscience. They found separate nerve pathways regulate diverse organ functions along the upper gastrointestinal (GI) tract, which is different from what researchers found in past studies. The lead investigator of this study is R. Alberto Travagli, professor, Department of Neural and Behavioral Sciences. Their findings were published on the Journal of Physiology. And this research was founded by NIH.
Brain cells control two distinct functions of the pancreas that one releases digestive enzymes, and the other one releases hormones like insulin and glucagon, while the neurotransmitters send signals to brain, such as vagus nerve regulates both of these pancreatic functions. The vagus nerve detects relative chemical and biological changers that happen along the GI tract. It likes a processing machine, then understand and integrate signals before which are sent back to organs and then brain and organ have corresponding actions.
One of these neurotransmitters is glutamate that acts upon different receptors. For example, it acts upon one major class of these receptors—metabotropic glutamate receptors (mGluRs) I, II or III depending on locations and nerve cell functions.
They focused on investigating the specialized structures that allow a signal to pass from one cell to another cell, and they wondered about whether pancreatic insulin and enzyme secretions are controlled by different types of vagal motoneurons through the vagus nerve.
They found if mGluRs glutamate acts on different subunit, different organ function will be presented, such as group II and III mGluRs can either activate or inhibit vagal nerve cells sending signals to the pancreas. But either group II or group III mGluR, insulin secretion will decrease and only group II mGluR can increase pancreatic enzyme secretion.
Their study results showed mGluRs on brainstem vagal nerve circuits are organized in a very specific manner. This is helpful for people to develop selective therapy or drugs by targeting on specific neruocircuits for patients, especially for diabetes, gastrointestinal reflux disorders, functional dyspepsia, gastroparesis and pancreatic exocrine or endocrine dysfunctions.