Effects of extracellular calcium on canine tracheal smooth muscle

Susan Gunst, J. M. Pisoni

Research output: Contribution to journalArticle

4 Citations (Scopus)

Abstract

Strips of canine tracheal smooth muscle were studied in vitro to determine the effects of changes in the extracellular calcium (Ca(o)) concentration on tonic contractions induced by acetylcholine and 5-hdyroxytryptamine. Strips were contracted with graded concentrations of the above agents in 2.4 mM Ca, after which CaCl2 was administered to achieve final concentrations of 5.0, 10.0, and 20.0 mM. Increases in Ca(o) to 5 mM or above caused significant relaxation of muscles contracted with 5-hydroxytryptamine but did not significantly relax muscles contracted with acetylcholine. Increases in Ca(o) also caused significant relaxation of muscles contracted with low concentrations of K+ (20 or 30 mM). However, in 60 or 120 mM K+, increases in Ca(o), resulted predominantly in muscle contraction. Inhibition of the Na+-K+-ATPase by ouabain (10-5 M) or K+ depletion reversed the effects of Ca(o) from relaxation to contraction in tissues contracted with 5-hydroxytryptamine. Increases in Ca(o) also caused contraction rather than relaxation in the presence of verapamil (10-6 M). We conclude that calcium has both excitatory and inhibitory effects on the contractile responses of canine tracheal smooth muscle. The inhibitory effects of Ca2+ appear to be linked to the activity of the membrane N+-K+-ATPase.

Original languageEnglish (US)
Pages (from-to)706-711
Number of pages6
JournalJournal of Applied Physiology
Volume61
Issue number2
StatePublished - 1986
Externally publishedYes

Fingerprint

Muscle Relaxation
Acetylcholine
Smooth Muscle
Canidae
Serotonin
Calcium
Ouabain
Muscle Contraction
Verapamil
Adenosine Triphosphatases
Muscles
Membranes
In Vitro Techniques
sodium-translocating ATPase

ASJC Scopus subject areas

  • Endocrinology
  • Physiology
  • Orthopedics and Sports Medicine
  • Physical Therapy, Sports Therapy and Rehabilitation

Cite this

Effects of extracellular calcium on canine tracheal smooth muscle. / Gunst, Susan; Pisoni, J. M.

In: Journal of Applied Physiology, Vol. 61, No. 2, 1986, p. 706-711.

Research output: Contribution to journalArticle

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