Evidence for a lower oesophageal sphincter in the guinea-pig

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Abstract

1. In vitro balloon pull-through experiments have been used to identify the guinea-pig lower oesophageal sphincter (LOS).

2 Histologically, the LOS forms a 1–2 mm ring of smooth muscle at the distal termination of the oesophagus, immediately adjacent to the gastric sling muscle.

3. Tetrodotoxin (10−6M) sensitive, guanethidine (10−6M) insensitive “on” relaxation of circular LOS muscle strips was evoked by electrical field stimulation (ES).

4. ES evoked atropine (10−6 M) sensitive “on” contractions of gastric sling and fundus smooth muscle strips.

5. Following cessation of ES a partially atropine-sensitive “off” contraction was observed in all the smooth muscle strips.

6. The predominant response of the LOS to ES was relaxation.

References (35)

  • C.S. Beck et al.

    Membrane activity in guineapig gastric sling muscle: a nerve dependent phenomenon

    Am. J. Physiol.

    (1971)
  • M.R. Bennett et al.

    An electrophysiological analysis of the storage of acetylcholine in preganglionic nerve terminals

    J. Physiol., (Lond.)

    (1972)
  • R.I. Burks et al.

    Acetylcholine metabolism of a sympathetic ganglion

    Can. J. Biochem. Physiol.

    (1961)
  • R.A.R. Bywater et al.

    Atropine-resistant depolarization in the guinea-pig small intestine

    J. Physiol., (Lond.)

    (1981)
  • J. Christensen

    Motor functions of the pharynx and oesophagus

  • J. Christensen et al.

    Physiological specialization at the oesophagogastric junction in three species

    Am. J. Physiol.

    (1973)
  • B. Costall et al.

    Field stimulation-induced responses of circular smooth muscle from guinea-pig stomach: characterization of the receptor mechanisms involved

    N.S. Arch. Pharm.

    (1983)
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