Distribution of neurokinin-2 receptors in the guinea-pig gastrointestinal tract

Andrea L. Portbury, John B. Furness, Bridget R. Southwell, Helen Wong, John H. Walsh, Nigel W. Bunnett

Research output: Contribution to journalArticlepeer-review


The distribution of neurokinin-2 (NK2) tachykinin receptors was investigated by immunohistochemistry in the guinea-pig oesophagus, stomach, small and large intestine. Receptor immunoreactivity occurred at the surfaces of smooth muscle cells throughout the digestive tract. Nerve fibre varicosities in enteric ganglia were also immunoreactive. In myenteric ganglia, these varicosities were most numerous in the ileum, frequent, but less dense, in the proximal colon and caecum, rare in the distal colon, extremely infrequent in the rectum and duodenum, and absent from the stomach and oesophagus. Reactive varicosities were rare in the submucous ganglia. Reactive nerve fibres in the mucosa were only found in the caecum and proximal colon. Strong NK2 receptor immunoreactivity was also found on the surfaces of enterocytes at the bases of mucosal glands in the proximal colon. Receptors were not detectable on the surfaces of nerve cells or on non-terminal axons. Reactivity did not occur on nerve fibres innervating the muscle. Denervation studies showed that the immunoreactive varicosities in the myenteric plexus of the ileum were the terminals of descending interneurons. Immunoreactivity for nitric oxide synthase was colocalised with NK2 receptor (NK-R) immunoreactivity in about 70% of the myenteric varicosities in the small intestine. Bombesin immunoreactivity occurred in about 30% of NK2-R immunoreactive varicosities in the small intestine.

Original languageEnglish (US)
Pages (from-to)281-292
Number of pages12
JournalCell and Tissue Research
Issue number3
StatePublished - 1996


  • Enteric nervous system
  • Gastrointestinal tract
  • Guinea pig
  • Peptide Receptors
  • Smooth muscle
  • Tachykinins

ASJC Scopus subject areas

  • Pathology and Forensic Medicine
  • Histology
  • Cell Biology


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