Article date: July 1994
By: Katrina A. Marsh, Stephen J. Hill, in Volume 112, Issue 3, pages 934-938
Dynamic video imaging was used to measure the des‐Arg9‐bradykinin‐induced changes in the intracellular free calcium ion concentration ([Ca2+]i) of single bovine tracheal smooth muscle (BTSM) cells.
In the presence of extracellular calcium ions, des‐Arg9‐bradykinin (1 nm–10 μm) produced a concentration‐dependent increase in the [Ca2+]i over basal levels yielding an EC50 value of 316 nm. The percentage of cells responding to each concentration of des‐Arg9‐bradykinin also increased in a concentration‐dependent manner (from 9% to 100%).
The bradykinin B2 receptor antagonist, d‐Arg[Hyp3,Thi5,8,d‐Phe7]‐bradykinin (10 μm), was without effect on the calcium response of the cells when added 2 min prior to des‐Arg9‐bradykinin (100 nm). However, the B1 receptor antagonist, des‐Arg9Leu8‐bradykinin (10 μm), completely abolished the des‐Arg9‐bradykinin‐induced response.
Under calcium‐free conditions, des‐Arg9‐bradykinin induced an increase in [Ca2+]i at concentrations of 1 μm and 10 μm. The response to 10 μm des‐Arg9‐bradykinin was reduced by preincubation of either d‐Arg[Hyp3,Thi5,8,d‐Phe7]‐bradykinin (10 μm) or des‐Arg9Leu8‐bradykinin (10 μm).
We conclude that bradykinin B1 receptors are expressed by cultured BTSM cells and mediate the des‐Arg9‐bradykinin‐induced influx of calcium ions at low agonist concentrations (< 1 μm). At higher concentrations, des‐Arg9‐bradykinin (1 μm and 10 μm) can stimulate both B1 and B2 receptors to effect intracellular calcium release under calcium‐free conditions.
Dynamic video imaging was used to measure the des‐Arg9‐bradykinin‐induced changes in the intracellular free calcium ion concentration ([Ca2+]i) of single bovine tracheal smooth muscle (BTSM) cells.
In the presence of extracellular calcium ions, des‐Arg9‐bradykinin (1 nm–10 μm) produced a concentration‐dependent increase in the [Ca2+]i over basal levels yielding an EC50 value of 316 nm. The percentage of cells responding to each concentration of des‐Arg9‐bradykinin also increased in a concentration‐dependent manner (from 9% to 100%).
The bradykinin B2 receptor antagonist, d‐Arg[Hyp3,Thi5,8,d‐Phe7]‐bradykinin (10 μm), was without effect on the calcium response of the cells when added 2 min prior to des‐Arg9‐bradykinin (100 nm). However, the B1 receptor antagonist, des‐Arg9Leu8‐bradykinin (10 μm), completely abolished the des‐Arg9‐bradykinin‐induced response.
Under calcium‐free conditions, des‐Arg9‐bradykinin induced an increase in [Ca2+]i at concentrations of 1 μm and 10 μm. The response to 10 μm des‐Arg9‐bradykinin was reduced by preincubation of either d‐Arg[Hyp3,Thi5,8,d‐Phe7]‐bradykinin (10 μm) or des‐Arg9Leu8‐bradykinin (10 μm).
We conclude that bradykinin B1 receptors are expressed by cultured BTSM cells and mediate the des‐Arg9‐bradykinin‐induced influx of calcium ions at low agonist concentrations (< 1 μm). At higher concentrations, des‐Arg9‐bradykinin (1 μm and 10 μm) can stimulate both B1 and B2 receptors to effect intracellular calcium release under calcium‐free conditions.
DOI: 10.1111/j.1476-5381.1994.tb13170.x
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