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: Contraction of the sheep middle cerebral, pulmonary and coronary arteries initiated by release of intracellular calcium.
    Author: Drummond RM, Wadsworth RM.
    Journal: J Auton Pharmacol; 1994 Apr; 14(2):109-21. PubMed ID: 8051197.
    Abstract:
    The aim of the study was to compare contraction initiated by intracellular Ca2+ release in the middle cerebral, coronary and pulmonary arteries of the sheep. With all three arteries from the sheep, incubation in Ca(2+)-free physiological salt solution (PSS) reduced agonist-induced contraction much more than occurred with the rabbit aorta. The intracellular Ca2+ store appeared to be of limited capacity, since contraction was transient in Ca(2+)-free conditions with most agonists. In the middle cerebral artery, contraction in Ca(2+)-free conditions was much reduced if a previous contraction had been obtained (for 5-hydroxytryptamine, 5-HT, from 11 +/- 4 to 1 +/- 0.5% of control contraction in 2.5 mM Ca2+), suggesting that the previous contraction had partly discharged the intracellular Ca2+ store. Contraction was less affected in the pulmonary artery and almost unaffected in the coronary artery (for 5-HT, from 15 +/- 1 to 11 +/- 1%) by a previous contraction in Ca(2+)-free conditions. Rings prepared from small branches of the pulmonary and coronary arteries were affected by Ca2+ deprivation in a similar manner to large diameter pulmonary and coronary artery rings. In Ca(2+)-free PSS, contraction induced by prostaglandin E2 was almost eliminated (3 +/- 1% of control contraction in 2.5 mM Ca2+), contractions induced by 5-HT and noradrenaline were reduced, and contraction induced by the thromboxane mimetic U46619 was least affected (up to 73 +/- 8%). Increasing agonist concentration from EC50 to the maximally effective concentration raised the percentage contraction remaining in the middle cerebral artery (for noradrenaline from 7 +/- 2% to 12 +/- 3%) but not in the pulmonary artery (for noradrenaline from 22 +/- 2% to 24 +/- 6%). The present study has revealed notable differences, in coupling to intracellular Ca2+ release between the three vascular territories studied.
    [Abstract] [Full Text] [Related] [New Search]