Background: Serotonin plays a pivotal role in regulating gut motility, visceral sensitivity, and fluid secretion via specific receptors. Among these receptors, 5-HT4 exerts a prominent control on gut motor function. Although the prokinetic effect exerted by 5-HT4 agonists is well known, the cellular sites of 5-HT4 expression remain poorly understood in large mammals, e.g., horses. In this study, we evaluated the distribution of 5-HT4 in the horse intestine and in foals with enteric aganglionosis, reminiscent of human Hirschsprung's disease. Methods: The intestine and spinal ganglia were obtained from three healthy horses and two foals with hereditary ileocolonic aganglionosis. Tissues were processed for immunohistochemistry using a specific antibody to 5-HT4 and a variety of neuronal markers. Myenteric and submucosal plexus 5-HT4-immunoreactive (IR) neurons were quantified as relative percentage (mean±SD) to the total number of neurons counted. Furthermore, the density of 5-HT4-IR nerve fibers was evaluated in the mucosa and tunica muscularis. Key Results: The 5-HT4 immunoreactivity was localized to large percentages of myenteric neurons ranging from 28±9% (descending colon) to 63±19% (ileum), and submucosal neurons ranging from 54±6% (ileum) to 68±14% (duodenum). The 5-HT4-immunoreactivity was co-expressed by some substance P-IR (SP-IR) spinal ganglion neurons and extrinsic sensory fibers of aganglionic foals. Conclusions & Inferences: The presence of 5-HT4 in many enteric and extrinsic sensory neurons and nerve fibers provides solid morphological evidence of the cellular sites of 5-HT4 expression in horses. The evidence of SP-IR sensory neurons positive for 5-HT4 suggests its role in visceral sensitivity.

Giancola, F., Rambaldi, A.M., Bianco, F., Iusco, S., Romagnoli, N., Tagliavia, C., et al. (2017). Localization of the 5-hydroxytryptamine 4 receptor in equine enteric neurons and extrinsic sensory fibers. NEUROGASTROENTEROLOGY AND MOTILITY, 29(7), 1-12 [10.1111/nmo.13045].

Localization of the 5-hydroxytryptamine 4 receptor in equine enteric neurons and extrinsic sensory fibers

GIANCOLA, FIORELLA;RAMBALDI, ANNA MARIA;BIANCO, FRANCESCA;IUSCO, SIMONA;ROMAGNOLI, NOEMI;TAGLIAVIA, CLAUDIO;BOMBARDI, CRISTIANO;CLAVENZANI, PAOLO;DE GIORGIO, ROBERTO;CHIOCCHETTI, ROBERTO
2017

Abstract

Background: Serotonin plays a pivotal role in regulating gut motility, visceral sensitivity, and fluid secretion via specific receptors. Among these receptors, 5-HT4 exerts a prominent control on gut motor function. Although the prokinetic effect exerted by 5-HT4 agonists is well known, the cellular sites of 5-HT4 expression remain poorly understood in large mammals, e.g., horses. In this study, we evaluated the distribution of 5-HT4 in the horse intestine and in foals with enteric aganglionosis, reminiscent of human Hirschsprung's disease. Methods: The intestine and spinal ganglia were obtained from three healthy horses and two foals with hereditary ileocolonic aganglionosis. Tissues were processed for immunohistochemistry using a specific antibody to 5-HT4 and a variety of neuronal markers. Myenteric and submucosal plexus 5-HT4-immunoreactive (IR) neurons were quantified as relative percentage (mean±SD) to the total number of neurons counted. Furthermore, the density of 5-HT4-IR nerve fibers was evaluated in the mucosa and tunica muscularis. Key Results: The 5-HT4 immunoreactivity was localized to large percentages of myenteric neurons ranging from 28±9% (descending colon) to 63±19% (ileum), and submucosal neurons ranging from 54±6% (ileum) to 68±14% (duodenum). The 5-HT4-immunoreactivity was co-expressed by some substance P-IR (SP-IR) spinal ganglion neurons and extrinsic sensory fibers of aganglionic foals. Conclusions & Inferences: The presence of 5-HT4 in many enteric and extrinsic sensory neurons and nerve fibers provides solid morphological evidence of the cellular sites of 5-HT4 expression in horses. The evidence of SP-IR sensory neurons positive for 5-HT4 suggests its role in visceral sensitivity.
2017
Giancola, F., Rambaldi, A.M., Bianco, F., Iusco, S., Romagnoli, N., Tagliavia, C., et al. (2017). Localization of the 5-hydroxytryptamine 4 receptor in equine enteric neurons and extrinsic sensory fibers. NEUROGASTROENTEROLOGY AND MOTILITY, 29(7), 1-12 [10.1111/nmo.13045].
Giancola, Fiorella; Rambaldi, ANNA MARIA; Bianco, Francesca; Iusco, Simona; Romagnoli, Noemi; Tagliavia, Claudio; Bombardi, Cristiano; Clavenzani, Pao...espandi
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Utilizza questo identificativo per citare o creare un link a questo documento: https://hdl.handle.net/11585/615914
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