The equine enteric nervous system — Neuron characterization and distribution in adults and juveniles

Doxey, D. L.; Pearson, Gemma; Milne, Elspeth; Gilmour, J.S.; Chisholm, H.k.

doi:10.1007/bf01839331

Cited by 15 publications

(14 citation statements)

References 12 publications

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“…Gabella (1971) observed in developing rats that the neuronal density decreased with age. Similar observations have been made in guinea-pigs, sheep, horses, pigs, and chick embryos (Gabella, 1987;Young et al, 1993;Doxey et al, 1995;Zhang et al, 2004;O′Donnell et al, 2006). Decreasing NADPH-dpositive neuron density in the developing pig model has been used to explain why primary intussusception does not occur in adults (Cserni et al, 2007).…”

Section: Discussionsupporting

confidence: 55%

Quantitative changes of nitrergic neurons during postnatal development of chicken myenteric plexus

Yang

Gandahi

Zhang

et al. 2013

J. Zhejiang Univ. Sci. B

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Abstract:Objective: Information regarding the development of the enteric nervous system (ENS) is important for understanding the functional abnormalities of the gut. Because fertilized chicken eggs provide easy access to embryos, chicken models have been widely used to study embryonic development of myenteric plexus; however, no study has been focused on the postnatal period. The aim of this study was to perform a qualitative and quantitative analysis of the nitrergic neurons in the myenteric plexus of developing chickens in the postnatal period. Methods: Whole-mount preparations of the myenteric plexus were made in 7-d, 15-d, and 40-d old (adult) chickens of either sex (n=15). The myenteric plexus was studied after nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) histochemistry using light microscopy, digital photography, and Image-Pro Plus 6.0 software. The numbers of positively stained neurons and ganglia were counted in the duodenum, jejunum, ileum, caecum, and colon in the different age groups. Data were expressed as mean±standard deviation (SD), and statistical analysis was performed using a one-way analysis of variance (ANOVA) test. Results: The positively stained neurons showed various morphologies and staining intensities, and formed bead-shaped and U-shaped arrangements in the myenteric plexus. The densities of neurons and ganglia increased with age. However, the number of positive neurons per ganglion increased. The number of NADPH-d-positive neurons was highest in the colon, followed by the ileum, the jejunum, the duodenum, and the caeca in all age groups. Conclusions: Developmental changes in the myenteric plexus of chickens continue in the postnatal period, indicating that the maturation process of the gastrointestinal function is gradual. In addition, no significant difference is happening among different intestinal segments during postnatal development, suggesting that the function of different intestinal segments had been determined after birth.

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Section: Discussionsupporting

confidence: 55%

Quantitative changes of nitrergic neurons during postnatal development of chicken myenteric plexus

Yang

Gandahi

Zhang

et al. 2013

J. Zhejiang Univ. Sci. B

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“…Neuronal loss in the myenteric plexus, as well as neuromuscular dysfunction, has been demonstrated to occur with human ageing (Hall, 2002;Hanani et al, 2004). In a study involving horses up to 20 years of age, Doxey et al (1995) found no decline in the number of small intestinal enteric neurons with increasing age. Additionally, Schusser and White (1997) found no significant difference in colonic neuronal density in normal horses that were 8 years old or less compared with animals over 8 years old.…”

Section: Discussionmentioning

confidence: 98%

Expression of PGP 9.5 by Enteric Neurons in Horses and Donkeys with and without Intestinal Disease

Hudson

Pearson

Mayhew

et al. 2014

Journal of Comparative Pathology

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SummaryIntestinal motility disorders are an important problem in horses and donkeys and this study was carried out in order to evaluate the enteric neurons in animals with and without intestinal disease. Surplus intestinal tissue samples were collected from 28 horses undergoing exploratory laparotomy for colic. In addition, surplus intestinal samples from 17 control horses were collected immediately following humane destruction for clinical conditions not relating to the intestinal tract. Similar samples were also collected during routine postmortem examinations from 12 aged donkeys; six animals were humanely destroyed for conditions related to the intestinal tract, while the remaining six were humanely destroyed for other reasons including dental and orthopaedic diseases. Tissue samples were fixed in formalin and immunohistochemical labelling was performed targeting the enteric neurons using a polyclonal antibody specific for the neuronal marker PGP 9.5. The distribution and density of neuronal networks were assessed qualitatively and semi-quantitatively. There was strong PGP 9.5 expression in both the horse and donkey samples and labelling was detected throughout the tissue sections. In both species, PGP 9.5-immunoreactive nerve fibres were detected in all layers of the intestinal tract, both in large and small intestinal samples.Networks of enteric neurons were present in the donkey with a similar distribution to that seen in the horse. There was no demonstrable difference in enteric neuronal density and distribution in the groups of animals with intestinal disease compared with those without, apart from two (out of 28) horses with intestinal disease that showed a marked reduction in PGP 9.5 immunoreactivity. Apart from these two animals, this total cohort analysis differs from some previously observed findings in horses with intestinal disease and may therefore reflect the different pathophysiological processes occurring in varying intestinal conditions resulting in colic both in the donkey and horse.

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“…The problem with previous research -in healthy horses -has been the use of 2-D quantitative microscopy methods (membrane preparations) for assessing enteric neurons [Pearson, 1994;Doxey et al, 1995;Freytag et al, 2008]. After perusing the literature, surprisingly, we have not yet found any 3-D design-based stereological data on the enteric nervous system of healthy and ICA horses.…”

Section: Introductionmentioning

confidence: 81%

“…Another study conducted on the ileum of healthy horses by Doxey et al [1995] estimated the number of neuron profiles in the myenteric and submucosal plexuses of horses as 8,808 and 14,352, respectively. Again, our estimates for the horse ileum were 5,264-and 1,144-fold higher, respectively.…”

Section: Discussionmentioning

confidence: 99%

3-D Technology Used to Accurately Understand Equine Ileocolonic Aganglionosis

Muniz

Ladd²,

Ladd³

et al. 2013

Cells Tissues Organs

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Ileocolonic aganglionosis (ICA) is the congenital and hereditary absence of neurons that constitute the enteric nervous system and has been described in various species including humans - Hirschsprung's disease - and horses - overo lethal white syndrome (OLWS). Hirschsprung's disease affects circa 1 in 5,000 live births. At best, this disease means an inability to absorb nutrients from food (humans). At worse, in horses, it always means death. Despite our general understanding of the functional mechanisms underlying ICA, there is a paucity of reliable quantitative information about the structure of myenteric and submucosal neurons in healthy horses and there are no studies on horses with ICA. In light of these uncertainties, we have used design-based stereology to describe the 3-D structure - total number and true size - of myenteric and submucosal neurons in the ileum of ICA horses. Our study has shown that ICA affects all submucosal neurons and 99% of myenteric neurons. The remaining myenteric neurons (0.56%) atrophy immensely, i.e. 63.8%. We believe this study forms the basis for further research, assessing which subpopulation of myenteric neurons are affected by ileocolonic aganglionosis, and we would like to propose a new nomenclature to distinguish between a complete absence of neurons - aganglionosis - and a weaker form of the disease which we suggest naming ‘hypoganglionosis'. Our results are a step forward in understanding this disease structurally.

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The equine enteric nervous system — Neuron characterization and distribution in adults and juveniles

Cited by 15 publications

References 12 publications

Quantitative changes of nitrergic neurons during postnatal development of chicken myenteric plexus

Quantitative changes of nitrergic neurons during postnatal development of chicken myenteric plexus

Expression of PGP 9.5 by Enteric Neurons in Horses and Donkeys with and without Intestinal Disease

3-D Technology Used to Accurately Understand Equine Ileocolonic Aganglionosis

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