These tools will no longer be maintained as of December 31, 2024. Archived website can be found here. PubMed4Hh GitHub repository can be found here. Contact NLM Customer Service if you have questions.


Pubmed for Handhelds

PUBMED FOR HANDHELDS

Search MEDLINE/PubMed

  • Title: Potassium and caffeine contractures in fast and slow muscles of the chicken.
    Author: Huerta M, Stefani E.
    Journal: J Physiol; 1981 Sep; 318():181-9. PubMed ID: 7320888.
    Abstract:
    1 K+ contractures, caffeine contractures and electrical properties were studied in slow (posterior latissimus dorsi; p.l.d.) and fast (anterior latissimus dorsi; a.l.d.) chicken muscles. 2. P.l.d. K+ contractures show a transient increase of tension that relaxes spontaneously. Contractures in a.l.d. show an initial component followed by a maintained tension. 3. A.l.d. K+ contractures of similar amplitude and time course were reproduced at 4 min intervals. In p.l.d., the interval needed for full recovery is about 30 min. In Cl-free saline p.l.d. and a.l.d. K+ contractures can be reproduced at 4 min intervals. 4. The time course of repolarization after a short exposure to 160 mM-KCl was much slower in p.l.d. than in a.l.d. In Cl-free saline the time course of repolarization becomes faster in p.l.d. 5. The membrane resistance was not modified in a.l.d. and was increased in p.l.d. by Cl-free saline. The calculated Cl- conductance in p.l.d. was about 70% of the total membrane conductance. 6. In a.l.d., Mn2+, D600 and external Ca2+ reduction greatly diminishes the maintained phase of the K+ contracture leaving the initial phase almost unmodified. Under similar conditions p.l.d. K+ contractures were slightly reduced. 7. P.l.d. caffeine contractures (10-40 mM) were not maintained and they were not modified by Ca-free saline, Cd2+, Co2+, Mn2+ and D600. 8. A.l.d. caffeine contractures (2-15 mM) were maintained and were highly dependent on external Ca2+. In addition they were greatly reduced by Cd2+, Co2+, Mn2 and D600. 9. It is suggested that caffeine contractures of a.l.d. are elicited by a Ca2+ entry into the muscle from the external fluid.
    [Abstract] [Full Text] [Related] [New Search]