Role of nitric oxide- and vasoactive intestinal polypeptide-containing neurones in human gastric fundus strip relaxations

M. Tonini, R. De Giorgio, F. De Ponti, C. Sternini, V. Spelta, P. Dionigi, G. Barbara, V. Stanghellini, R. Corinaldesi

Research output: Contribution to journalArticle

Abstract

1. The morphological pattern and motor correlates of nitric oxide (NO) and vasoactive intestinal polypeptide (VIP) innervation in the human isolated gastric fundus was explored. 2. By using the nicotinamide adenine dinucleotide phosphate hydrogen (NADPH)-diaphorase and specific rabbit polyclonal NO-synthase (NOS) and VIP antisera, NOS- and VIP-containing varicose nerve fibres were identified throughout the muscle layer or wrapping ganglion cell bodies of the myenteric plexus. NOS-immunoreactive (IR) neural cell bodies were more abundant than these positive for VIP-IR. The majority of myenteric neurones containing VIP coexpressed NADPH-diaphorase. 3. Electrical stimulation of fundus strips caused frequency-dependent NANC relaxations. N(G)-nitro-L-arginine (L-NOARG: 300 μM) enhanced the basal tone, abolished relaxations to 0.3-3 Hz (5 s) and those to 1 Hz (5 min), markedly reduced (~ 50) those elicited by 10-50 Hz, and unmasked or potentiated excitatory cholinergic responses at frequencies ≥ 1 Hz. L-NOARG-resistant relaxations were virtually abolished by VIP (100 nM) desensitization at all frequencies. 4. Relaxations to graded low mechanical distension (≤ l g) were insensitive to tetrodotoxin (TTX: 1 μM) and L-NOARG (300 μM), while those to higher distensions (2 g) were slightly inhibited by both agents to the same extent (~ 25). 5. In the human gastric fundus, NOS- and VIP immunoreactivities are colocalized in the majority of myenteric neurones. NO and VIP mediate electrically evoked relaxations: low frequency stimulation, irrespective of the duration, caused NO release only, whereas shortlasting stimulation at high frequencies induced NO and VIP release. Relaxations to graded mechanical distension were mostly due to passive viscoelastic properties, with a slight NO-mediated neurogenic component at 2 g distension. The difference between NO and VIP release suggests that in human fundus accommodation is initiated by NO.

Original languageEnglish
Pages (from-to)12-20
Number of pages9
JournalBritish Journal of Pharmacology
Volume129
Issue number1
Publication statusPublished - 2000

Keywords

  • Electrically-induced relaxations
  • Human gastric fundus
  • Mechanically-induced relaxations
  • NADPH-diaphorase histochemistry
  • NANC inhibitory nerves
  • VIP and NOS-immunohistochemistry

ASJC Scopus subject areas

  • Pharmacology

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  • Cite this

    Tonini, M., De Giorgio, R., De Ponti, F., Sternini, C., Spelta, V., Dionigi, P., Barbara, G., Stanghellini, V., & Corinaldesi, R. (2000). Role of nitric oxide- and vasoactive intestinal polypeptide-containing neurones in human gastric fundus strip relaxations. British Journal of Pharmacology, 129(1), 12-20.