Sympathetic innervation of the ileocecal junction in horses

Abstract

The distribution and chemical phenotypes of sympathetic and dorsal root ganglion (DRG) neurons innervating the equine ileocecal junction (ICJ) were studied by combining retrograde tracing and immunohistochemistry. Immunoreactivity (IR) for tyrosine hydroxylase (TH), dopamine beta-hydroxylase (DBH), neuronal nitric oxide synthase (nNOS), calcitonin gene-related peptide (CGRP), substance P (SP), and neuropeptide Y (NPY) was investigated. Sympathetic neurons projecting to the ICJ were distributed within the celiac (CG), cranial mesenteric (CranMG), and caudal mesenteric (CaudMG) ganglia, as well as in the last ganglia of the thoracic sympathetic chain and in the splanchnic ganglia. In the CG and CranMG 91 +/- 8% and 93 +/- 12% of the neurons innervating the ICJ expressed TH- and DBH-IR, respectively. In the CaudMG 90 +/- 15% and 94 +/- 5% of ICJ innervating neurons were TH- and DBH-IR, respectively. Sympathetic (TH-IR) fibers innervated the myenteric and submucosal ganglia, ileal blood vessels, and the muscle layers. They were more concentrated at the ICJ level and were also seen encircling myenteric plexus (MP) and submucosal plexus (SMP) descending neurons that were retrogradely labeled from the ICJ. Among the few retrogradely labeled DRG neurons, nNOS-, CGRP-, and SP-IR nerve cells were observed. Dense networks of CGRP-, nNOS-, and SP-IR varicosities were seen around retrogradely labeled prevertebral ganglia neurons. The CGRP-IR fibers are probably the endings of neurons projecting from the intestine to the prevertebral ganglia. These findings indicate that this crucial region of the intestinal tract is strongly influenced by the sympathetic system and that sensory information of visceral origin influences the sympathetic control of the ICJ.

Localization and neurochemical characteristics of the extrinsic sympathetic neurons projecting to the pylorus in the domestic pig

“…The discrepancy concerning the paravertebral ganglia may result from different lengths of the examined gastrointestinal tract sections in these tracing experiments. Although the neurons of the sympathetic trunk ganglia are considered to control the blood flow within the gastrointestinal tract, a tracing study on the innervation of the ileocecal junction in horses disclosed only solitary perikarya in the last three thoracic sympathetic chain ganglia (Russo et al, 2010). This observation seems to be particularly suggestive in view of the anatomy of the ileocecal junction in horses, which appears as an angio-muscular system with dense submucosal venous plexus (Kotze, 1988(Kotze, , 1990.…”

Expression of high‐molecular‐mass neurofilament protein in horse (Equus caballus) spinal ganglion neurons

“…Specificity of anti-SP and anti-nNOS antibodies as well as the IB4 used in this study, have already been tested earlier (Russo et al, 2010;2011). The anti-NF200 antibody (Sigma-Aldrich, N4142) utilized in this study was tested for its specificity by Western blot (WB) analysis (Fig.…”

Effects of aging on the architecture of the ileocecal junction in rats

“…Previous studies have shown the presence of NOS in the enteric ganglia and muscle fibers under various conditions, such as malnutrition and renutrition [27,28] , ischemia and reperfusion [29][30][31] and obesity [32,33] . The enteric neurons of the ICJ stain positive for NOS, PGP 9.5, and c-kit [3,4,6,8] . Additionally, neuronal nitric oxide synthase (nNOS) is present in the myenteric, the submucosal ganglia and the IJC muscle layers in horse [8] .…”

“…The enteric neurons of the ICJ stain positive for NOS, PGP 9.5, and c-kit [3,4,6,8] . Additionally, neuronal nitric oxide synthase (nNOS) is present in the myenteric, the submucosal ganglia and the IJC muscle layers in horse [8] . In our study, we noticed the presence of NOS in the muscle layers and neurons in the ICJs of both the young and elderly groups, but we did not observe a difference in the intensity of the stain for HuC/D or NOS between groups.…”

“…Morphological differences between species can be related to the type of digestion, either partial or total, in the cecum [5][6][7][8] . The smooth muscle cells of the ICJ maintain a high tone [9] .…”