Development of neuropeptide Y-ergic innervation of the small intestine in rats

Abstract

Neuropeptide Y (NPY) acts as a neurotransmitter in the autonomic nervous system, including in the metasympathetic intramural ganglia of the intestine. In this study, NPY-positive neurons were detected using immunohistochemical methods in intramural ganglia of the duodenum in the following age groups of rats: newborn pups; 10-, 20-, 30-, and 60-day-old; 1- and 2-year-old rats. As a result of the immunohistochemical analysis, the NPY-containing neurons were found in small number in the intramural ganglia of the myenteric plexus from the moment of birth and during other periods of life. In ganglia of the submucosal plexus, NPY-immunoreac­tive neurons were detected in large numbers only starting from day 10 of life. Their proportion did not change until the age of one year and then decreased in the two-year-old rats. The density of Y1R and Y2R receptors increased, while the proportion of Y5R receptors decreased. These changes can be associated with the trophic action of the NPY. It was concluded that neuropeptide Y is a fairly common neuropeptide in various parts of the autonomic nervous system, including sympathetic, parasympathetic, and metasympathetic, and plays an important role in the processes of age-related neuronal development.

Keywords

• neuropeptide y
• receptors
• autonomic nervous system
• rats
• ontogenesis