Age-Related Changes of Calbindin D-28k-Immunoreactive Neurons in the Myenteric Plexus of Gerbil Duodenum

Abstract

ABSTRACT. We examined the age-related changes of calbindin D-28k (CB)-immunoreactive neurons and overall populations of neurons in the myenteric plexus of gerbil duodenum using whole mount preparations and immunohistochemistry. The circumference of duodenum increased age-dependently. CB-immunoreactive neurons were observed in all groups, and most of them had the Dogiel type II morphology. The fully developed cobweb-like structures were observed in the myenteric plexus of duodenum at postnatal month (PM) 3 to 24. Although the highest numbers of CB-immunoreactive neurons and overall population were observed in PM 1.5, it is related with significant increase of the size of circumference between PM 1.5 to PM 3. CB-immunoreactive neurons were slightly decreased with age between PM 3 to PM 24. We have also found that whole numbers of myenteric neurons were also significantly decreased in PM 24 group. These results suggest that loss of overall numbers of myenteric neurons and CB-immunoreactive neurons may be related with age-related neurodegeneration and functional loss of duodenum in the gerbil. KEY WORDS: aging, calbindin, duodenum, gerbil, myenteric plexus.J. Vet. Med. Sci. 70(4): 343-348, 2008 The autonomic nervous system is divided into two divisions, e.g. parasympathetic nervous system and sympathetic nervous system. In recent decade, the enteric nervous system (ENS) is the largest division of the autonomic nervous system, because it can perform its function independently from the central nervous system [7,20,44]. It consists of local nerve networks embedded in the gut wall and is subdivided into two ganglionated plexuses, i.e., the submucosal and myenteric plexuses [40,44]. The ENS mediates complex reflex activities involving intestinal motility, mucosal transportation and blood flow [7]. In electrophysiological studies, the majority of the enteric neurons could be placed in one of two classes: synaptic neurons or after-hyperpolarizing (AH) neurons [21,22,26,29,34].The myenteric plexus lies between the longitudinal and circular muscular layers and extends entire length of the gut. It has been known that the myenteric plexus primarily provides motor innervation to the two muscular layers and secremotor innervation to the mucosa [15,44].Calbindin D-28k (CB), one of the calcium binding proteins, plays an important role as an intracellular facilitator of calcium diffusion or as a modulator of neurotransmission [3,4,16,17]. In neurons, action potentials are also carried in part by inward calcium current [22,26,34]. It has been reported that AH neurons were sensory neurons because these neurons lacked fast excitatory synaptic inputs [21,22,26,29,34]. More recently, with the help of the combination of the electrophysiological and immunohistochemical methods, it has been identified that the AH neurons had Dogiel type II morphology [14,18,26].Although the distribution of CB-containing neuronal system has been reported upon the forebrain [11,23,24], comprehensive knowledge about the maturation of CB neurons in myenteri...

Age-Related Changes in the myenteric Plexus of the Gastric Fundus in Albino Rats

“…Thus, it is highly specialized both functionally and structurally [7]. Thus, it is highly specialized both functionally and structurally [7].…”

Reduction of Calbindin D-28k-Immunoreactive Neurons in the Dog Dentate Gyrus

“…Although many studies on age-related changes in CB expression in the nervous system have been conducted in various species [1,3,14,18,19,[23][24][25], few reports have demonstrated the expression of CB in the aged dog brain. Therefore we examined changes in CB immunoreactivity in the dentate gyrus of dogs of various ages in order to elucidate the correlation between age and changes in CB.…”

“…Immunohistochemistry for CB was performed by the method of a previous study [3]. In brief, the sections were incubated with diluted mouse anti-CB (1:2,000, Swant, Bellinzona, Switzerland) and subsequently exposed to biotinylated goat anti-mouse IgG and streptavidin peroxidase complex (1:200, Vector, Burlingame, CA, U.S.A.).…”