Sustained norepinephrine contraction in the rat portal vein is lost when Ca(2+) is replaced with Sr(2+).

• Agonist-induced activation of smooth muscle involves a rise in intracellular Ca(2+) concentration and sensitization of myosin light chain phosphorylation to Ca(2+). Sr(2+) can enter through Ca(2+) channels, be sequestered and released from sarcoplasmic reticulum, and replace Ca(2+) in activation of myosin light chain phosphorylation. Sr(2+) cannot replace Ca(2+) in facilitation of agonist-activated Ca(2+)-dependent nonselective cation channels. It is not known whether Sr(2+) can replace Ca(2+) in small G protein-mediated sensitization of phosphorylation. To explore mechanisms involved in alpha-receptor-activated contractions in smooth muscle, effects of replacing Ca(2+) with Sr(2+) were examined in rat portal vein. Norepinephrine (NE) at

Subject headings

MEDICIN OCH HÄLSOVETENSKAP  -- Medicinska och farmaceutiska grundvetenskaper (hsv//swe)

MEDICAL AND HEALTH SCIENCES  -- Basic Medicine (hsv//eng)

Keyword

Smooth

Guanosine 5'-O-(3-Thiotriphosphate)/pharmacology

Muscle

Vascular/metabolism

Norepinephrine/*pharmacology

Portal Vein/*metabolism

Potassium/pharmacology

Rats

Sprague-Dawley

Support

Strontium/*pharmacokinetics

Non-U.S. Gov't

Vasoconstrictor Agents/*pharmacology

Vasoconstriction/drug effects/physiology

Female

Calcium/*pharmacokinetics

Animal

Publication and Content Type

art (subject category)

ref (subject category)