Neural regulation of in vitro giant contractions in the rat colon

A. Gonzalez, S. K. Sarna

Research output: Contribution to journalArticle

41 Citations (Scopus)

Abstract

The rat middle colon spontaneously generates regularly occurring giant contractions (GCs) in vitro. We investigated the neurohumoral and intracellular regulation of these contractions in a standard muscle bath. cGMP content was measured in strips and single smooth muscle cells. The circular muscle strips generated spontaneous GCs. Their amplitude and frequency were significantly increased by tetrodotoxin (TTX), ω-conotoxin, Nω-nitro-L-arginine (L-NNA), and the dopamine D1 receptor antagonist Sch-23390. The GCs were unaffected by hexamethonium, atropine, and antagonists of serotonergic (5-HT1-4), histaminergic (H1-2), and tachykininergic (NK1-2) receptors but enhanced by NK3 receptor antagonism. The guanylate cyclase inhibitor 1H-[1,2,4]oxidiazolo[4,3-alquinoxalin-1-one (ODQ) also enhanced GCs to the same extent as TTX and L-NNA, and each of the three agents prevented the effects of the others. GCs were abolished by electrical field stimulation, S-nitroso-N-acetyl-penicillamine, and 8-bromo-cGMP. BAY-K-8644 and apamin enhanced the GCs, but they were abolished by D-600. Basal cGMP content in strips was decreased by TTX, L-NNA, or ODQ, but these treatments had no effect on cGMP content of enzymatically dissociated single smooth muscle cells. We conclude that spontaneous contractions in the rat colonic muscle strips are not generated by cholinergic, serotonergic, or histaminergic input. Constitutive release of nitric oxide from enteric neurons sustains cGMP synthesis in the colonic smooth muscle to suppress spontaneous in vitro GCs.

Original languageEnglish
JournalAmerican Journal of Physiology - Gastrointestinal and Liver Physiology
Volume281
Issue number1 44-1
StatePublished - 2001
Externally publishedYes

Fingerprint

Tetrodotoxin
Colon
Muscles
Smooth Muscle Myocytes
Conotoxins
Serotonin 5-HT1 Receptor Antagonists
Gallopamil
Apamin
Dopamine D1 Receptors
Hexamethonium
Penicillamine
Dopamine Antagonists
Guanylate Cyclase
Baths
Atropine
Cholinergic Agents
Electric Stimulation
Smooth Muscle
Arginine
Nitric Oxide

Keywords

  • Apamin
  • Calcium channels
  • Cholinergic
  • Dopamine
  • Enteric neurons
  • Guanosine 3′,5′-cyclic monophosphate
  • Nitric oxide
  • Nonadrenergic
  • Noncholinergic
  • Tachykinins

ASJC Scopus subject areas

  • Gastroenterology
  • Physiology
  • Physiology (medical)

Cite this

Neural regulation of in vitro giant contractions in the rat colon. / Gonzalez, A.; Sarna, S. K.

In: American Journal of Physiology - Gastrointestinal and Liver Physiology, Vol. 281, No. 1 44-1, 2001.

Research output: Contribution to journalArticle

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