Adenosine induces mesangial cell contraction by an A1-type receptor

Area of Science:

• Nephrology
• Cell Biology
• Pharmacology

Background:

• Adenosine is known to reduce renal blood flow and glomerular filtration rate.
• The specific effects of adenosine on mesangial cells and the underlying receptor mechanisms remain unclear.

Purpose of the Study:

• To investigate the hypothesis that adenosine induces contractile effects on mesangial cells.
• To identify the specific adenosine receptor subtype (A1 or A2) involved in this response.
• To determine the role of calcium in adenosine-mediated mesangial cell contraction.

Main Methods:

• Cultured rat mesangial cells were treated with varying concentrations of adenosine.
• Cell contraction was quantified by measuring changes in planar cell surface area (PCSA).
• Selective adenosine receptor agonists and antagonists, as well as verapamil and calcium-free conditions, were used to elucidate the mechanism.

Main Results:

• Adenosine induced a time- and dose-dependent reduction in PCSA, indicating mesangial cell contraction.
• The A1 receptor antagonist PD116,948 blocked adenosine-induced contraction, while the A2 antagonist PD115,199 did not.
• The A1 agonist S-PIA decreased PCSA, whereas the A2 agonist NECA did not.
• Verapamil and calcium-free medium prevented adenosine-induced contraction, highlighting the dependence on calcium influx.

Conclusions:

• Adenosine induces specific contraction of cultured rat mesangial cells.
• This contraction is primarily mediated by the adenosine A1 receptor.
• Extracellular calcium influx is essential for adenosine-induced mesangial cell contraction.