The Role of a Ryanodine-Sensitive Ca2+-Store in the Regulation of Smooth Muscle Tone of the Cat Gastric Fundus

Georgi Petkov, K. K. Boev

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

The smooth muscle of the gastric fundus maintains spontaneous tone, but the mechanism underlying this activity is not fully understood. The aim of the present study was to examine whether Ca2+ release from the sarcoplasmic reticulum (SR) could play a role in the maintenance of the spontaneous smooth muscle tone of the cat gastric fundus. The effects on the contractile activity of SR Ca2+ release activators ryanodine and caffeine and of the inhibitor ruthenium red were studied. The contractile activity of isolated muscle strips was recorded under isometric conditions using organ baths. Ryanodine concentration-dependently (10-7-3.10-5 mol/1) increased the tone of the fundus strips. In the presence of nifedipine (10-5 mol/1), ryanodine induced a nifedipine-resistant tonic contraction. The tonic contraction induced after inhibition of the SR Ca2+-pump by cyclopiazonic acid was potentiated by ryanodine (10-5 mol/1). In strips precontracted with supramaximal concentration of acetyl-choline (10-5 mol/1), ryanodine (3.10-5 mol/1) further potentiated the tone. Caffeine (10-4-10-2 mol/1) decreased and even completely inhibited the tone, suggesting some other effects of caffeine. Ruthenium red concentration-dependently (10-6-10-4 mol/1) decreased the tone. The present data provide evidence for the role of Ca2+ release from a SR ryanodine-sensitive Ca2+ store in the maintenance of the muscle tone of the cat gastric fundus.

Original languageEnglish (US)
Pages (from-to)225-237
Number of pages13
JournalGeneral Physiology and Biophysics
Volume17
Issue number3
StatePublished - Sep 1 1998
Externally publishedYes

Fingerprint

Gastric Fundus
Ryanodine
Smooth Muscle
Cats
Sarcoplasmic Reticulum
Caffeine
Ruthenium Red
Nifedipine
Maintenance
Muscles
Choline
Baths

All Science Journal Classification (ASJC) codes

  • Biophysics
  • Medicine(all)
  • Physiology

Cite this

The Role of a Ryanodine-Sensitive Ca2+-Store in the Regulation of Smooth Muscle Tone of the Cat Gastric Fundus. / Petkov, Georgi; Boev, K. K.

In: General Physiology and Biophysics, Vol. 17, No. 3, 01.09.1998, p. 225-237.

Research output: Contribution to journalArticle

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