title: Tachykinins mediate vagal inhibition of gastrin secretion in pigs.
abstract: OBJECTIVE
  Electrical vagal stimulation activates both stimulatory and inhibitory nerve fibers regulating gastrin release in the porcine antrum. The aim of this study was to examine the role of tachykinins in the inhibitory vagal control of gastrin release in the porcine antrum.
  
  
  METHODS
  Tachykinin presence was examined by immunohistochemistry and specific radioimmunoassays. Effects of electrical vagus stimulation and capsaicin infusion on tachykinin, gastrin, and somatostatin release were studied using the isolated perfused porcine antrum with intact vagal innervation. Effects of substance P and neurokinin A on gastrin and somatostatin secretion were investigated using nonpeptide neurokinin 1 and 2 receptor antagonists and somatostatin immunoneutralization.
  
  
  RESULTS
  Porcine antrum contained substance P and neurokinin A and did not contain neurokinin B, with immunoreactive nerves situated close to gastrin- and somatostatin-immunoreactive cells. Vagus stimulation released substance P, neurokinin A, gastrin, and somatostatin, whereas capsaicin stimulated only tachykinin release Tachykinin infusions increased somatostatin and decreased gastrin secretion, the latter being unaffected by somatostatin immunoneutralization and both being blocked by a combination of neurokinin 1 and 2 receptor antagonists, which also increased gastrin output during vagal stimulation.
  
  
  CONCLUSIONS
  Tachykinins strongly inhibit gastrin and stimulate somatostatin secretion in porcine antrum, and tachykininergic nerves mediate inhibitory vagal regulation of gastrin release.
authors.affiliation: Department of Medical Physiology, Panum Institute, Copenhagen, Denmark.
authors.forename: P
authors.initials: P
authors.lastname: Schmidt
authors.forename: S S
authors.initials: SS
authors.lastname: Poulsen
authors.forename: L
authors.initials: L
authors.lastname: Hilsted
authors.forename: T N
authors.initials: TN
authors.lastname: Rasmussen
authors.forename: J J
authors.initials: JJ
authors.lastname: Holst
mesh_terms: D000818:Animals; D005755:Gastrins / Q000378:metabolism*; D007150:Immunohistochemistry; D015288:Neurokinin A / Q000494:pharmacology; D010477:Perfusion; D011706:Pyloric Antrum / Q000294:innervation / Q000378:metabolism; D013004:Somatostatin / Q000378:metabolism; D013552:Swine; D015320:Tachykinins / Q000032:analysis / Q000502:physiology*; D014630:Vagus Nerve / Q000502:physiology*
chemical_list: D005755:Gastrins; D015320:Tachykinins; D013004:Somatostatin; D015288:Neurokinin A