Prostaglandins and tetrodotoxin-insensitive relaxation of opossum lower esophageal sphincter

E. E. Daniel, J. Crankshaw, S. Sarna

Research output: Contribution to journalArticle

Abstract

Field stimulation with pulses of 0.5 or 5 ms relaxed isolated strips of lower esophageal sphincter (LES) of the opossum; only responses to 0.5-ms pulses were inhibited by tetrodotoxin. Black widow spider venom prevented relaxation to both stimuli; thus both stimuli may release nonadrenergic inhibitory mediator. Isoproterenol, but not PGEs or ATP, was a consistent relaxant of LES. PGF(2α) (~1 μg/ml) and stable endoperoxides (~10 ng/ml) stimulated LES muscle. Doses of indomethacin (IDM) or 5,8,11,14-eicosatetraynoic acid (ETA), which inhibited contractions to arachidonic acid increased then abolished LES tone, inhibited relaxations to 5-ms pulses and less effectively to 0.5-ms pulses. Inhibition of relaxation preceded loss of tone. Tone could be restored by carbachol, PGEs, or PGF(2α) and relaxation after IDM but not ETA was also restored. Prostaglandins may participate in functioning of nonadrenergic inhibitory nerves and in maintaining sphincter tone. Cells that did not appear to be smooth muscle were in gap junction contact with smooth muscles and closely apposed to nerves with small agranular vesicles. A role for these structures, which are postulated to be interstitial cells, in tetrodotoxin-insensitive prostaglandin-related release of nonadrenergic inhibitory mediator was proposed.

Original languageEnglish (US)
JournalAmerican Journal of Physiology Endocrinology Metabolism and Gastrointestinal Physiology
Volume5
Issue number2
StatePublished - 1979
Externally publishedYes

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Opossums
Lower Esophageal Sphincter
Tetrodotoxin
Prostaglandins
5,8,11,14-Eicosatetraynoic Acid
Prostaglandins F
Prostaglandins E
Indomethacin
Smooth Muscle
Gap Junctions
Carbachol
Isoproterenol
Arachidonic Acid
Adenosine Triphosphate
Muscles

ASJC Scopus subject areas

  • Medicine(all)

Cite this

Prostaglandins and tetrodotoxin-insensitive relaxation of opossum lower esophageal sphincter. / Daniel, E. E.; Crankshaw, J.; Sarna, S.

In: American Journal of Physiology Endocrinology Metabolism and Gastrointestinal Physiology, Vol. 5, No. 2, 1979.

Research output: Contribution to journalArticle

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