Fall in density, but not number of myenteric neurons and circular muscle nerve fibres in guinea-pig colon with ageing

C. J. Peck, S. D. Samsuria, A. M. Harrington, S. K. King, J. M. Hutson, B. R. Southwell

Research output: Contribution to journalArticle

27 Citations (Scopus)

Abstract

In guinea-pig ileum, ageing has been associated with a decrease in enteric neurons. This study examined guinea-pig colon and measured changes in gut dimensions, neuron size, density and ganglionic area. Changes in motor nerve fibres in the circular muscle were also measured. Myenteric neurons in whole-mount preparations of mid-colon from 2-week, 6-month, and 2-year-old guinea-pigs were labelled immunohistochemically with the neuronal marker human neuronal protein HuC/HuD, and numbers of neurons mm-2, neuronal size, ganglionic area mm-2, gut length, circumference and muscle thickness were measured. Corrected numbers of neurons mm-2 and ganglionic area mm-2 accounting for growth of the colon were calculated. Additionally, nerve fibres in circular muscle cross-sections were labelled with antibodies against nitric oxide synthase (NOS) and substance P (SP) and the density of nerve fibres in circular muscle was measured. The numbers of neurons mm-2 decreased by 56% (from 2 weeks to 2 years) with no change in neuron size. Total neuron numbers decreased by 19% (P = 0.14) when adjusted for changes in length and circumference with age. The percentage area of NOS- and SP-immunoreactive (IR) nerve fibres in the circular muscle decreased (P < 0.001), but the total area of NOS and SP-IR nerve fibres increased (P < 0.01) due to an age-related increase in muscle thickness. The density of myenteric neurons in guinea-pig mid-colon halved from 2 weeks to 2 years, but when the increase in colon dimensions was considered, the number of neurons decreased by only 19%. The percentage area of motor nerve fibres in the circular muscle decreased with no change in total volume of nerve fibres.

Original languageEnglish
Pages (from-to)1075-e90
JournalNeurogastroenterology and Motility
Volume21
Issue number10
DOIs
Publication statusPublished - 1 Oct 2009
Externally publishedYes

Keywords

  • Ageing
  • Colon
  • Enteric neurons
  • Nitric oxide synthase
  • Substance P

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