Premium
The relationship of KCl‐ and prostaglandin F 2α ‐mediated increases in tension of the porcine coronary artery with changes in intracellular Ca 2+ measured with fura‐2
Author(s) -
Balwierczak Joseph L.
Publication year - 1991
Publication title -
british journal of pharmacology
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 2.432
H-Index - 211
eISSN - 1476-5381
pISSN - 0007-1188
DOI - 10.1111/j.1476-5381.1991.tb12438.x
Subject(s) - cromakalim , chemistry , contraction (grammar) , fura 2 , sodium nitroprusside , muscle contraction , intracellular , medicine , prostaglandin , muscle tension , biophysics , calcium , endocrinology , sodium , biochemistry , biology , nitric oxide , receptor , organic chemistry , cytosol , physical medicine and rehabilitation , enzyme , agonist
1 Changes in intracellular free Ca 2+ concentration ([Ca 2+ ] i ) were measured simultaneously with changes in muscle tension by use of the fluorescent Ca 2+ indicator, fura‐2, in coronary arterial rings of the Pig. 2 Changes in [Ca 2+ ] i were measured by monitoring the ratio of fluorescence due to excitation at 340 nm (F 340 ) to that at 380 nm (F 380 ). 3 Increases in tension of the porcine coronary artery induced by prostaglandin F 2α (PGF 2α ) (2–30 μ m ) and KCl (25–70 m m ) were accompanied by increases in the F 340 /F 380 fluorescence ratio of fura‐2. 4 KCl‐induced increases in muscle tension, equivalent to those produced by PGF 2α , were observed to occur in the presence of a higher [Ca 2+ ] i . 5 Nearly complete relaxation of KCl‐induced contractions by sodium nitroprusside (SNP) was accompanied by only a partial reversal of the increase in [Ca 2+ ] i that occurred during contraction. 6 Complete relaxation of the PGF 2α ‐contracted coronary artery by cromakalim (BRL 34915) was accompanied by a nearly complete reversal of the increase in [Ca 2+ ] i caused by the contractile agent. 7 The contractile state of smooth muscle is not an indicator of [Ca 2+ ] i . The [Ca 2+ ] i tension relationship is dependent upon the type of pharmacological agent that is used to change muscle tension.