Effect of extracellular ATP on contraction, cytosolic calcium activity, membrane voltage and ion currents of rat mesangial cells in primary culture

Br J Pharmacol. 1993 Aug;109(4):953-9. doi: 10.1111/j.1476-5381.1993.tb13713.x.


1. The effects of extracellular ATP on contraction, membrane voltage (Vm), ion currents and intracellular calcium activity [Ca2+]i were studied in rat mesangial cells (MC) in primary culture. 2. Addition of extracellular ATP (10(-5) and 10(-4) M) to MC led to a cell contraction which was independent of extracellular calcium. 3. Membrane voltage (Vm) and ion currents were measured with the nystatin patch clamp technique. ATP induced a concentration-dependent transient depolarization of Vm (ED50: 2 x 10(-6) M). During the transient depolarization ion currents were monitored simultaneously and showed an increase of the inward- and outward current. 4. In a buffer with a reduced extracellular chloride concentration (from 145 to 30 mM) ATP induced a depolarization augmented to -4 +/- 4 mV. 5. ATP-gamma-S and 2-methylthio-ATP depolarized Vm to the same extent as ATP, whereas alpha,beta-methylene-ATP (all 10(-5) M) had no effect on Vm. 6. The Ca2+ ionophore, A23187, depolarized Vm transiently from -51 +/- 2 to -28 +/- 4 mV and caused an increase of the inward current. 7. The intracellular calcium activity [Ca2+]i was measured with the fura-2 technique. ATP stimulated a concentration-dependent increase of [Ca2+]i (ED50: 5 x 10(-6) M). The increase of [Ca2+]i was biphasic with an initial peak followed by a sustained plateau. 8. The [Ca2+]i peak was still present in an extracellular Ca(2+)-free buffer, whereas the plateau was abolished. Verapamil (10(-4) M) did not inhibit the [Ca2+]i increase induced by ATP. 9. The data indicate that extracellular ATP contracts MC and is able to increase [Ca2+]i by the release of Ca2+ from intracellular stores and recruitment from the extracellular space. In addition ATP depolarizes Vm of MC by activating a Cl- conductance. The ATP-induced depolarization is mediated by a P2y receptor.

Publication types

  • Research Support, Non-U.S. Gov't

MeSH terms

  • Adenosine Triphosphate / analogs & derivatives
  • Adenosine Triphosphate / metabolism
  • Adenosine Triphosphate / pharmacology*
  • Animals
  • Calcimycin / pharmacology
  • Calcium / metabolism*
  • Cells, Cultured
  • Chlorides / metabolism
  • Cytosol / drug effects
  • Cytosol / metabolism
  • Extracellular Space / metabolism
  • Glomerular Mesangium / cytology
  • Glomerular Mesangium / drug effects*
  • Glomerular Mesangium / metabolism
  • Ion Channels / drug effects
  • Ion Channels / metabolism*
  • Membrane Potentials / drug effects
  • Muscle Contraction / drug effects
  • Nystatin / pharmacology
  • Rats
  • Receptors, Purinergic / drug effects
  • Verapamil / pharmacology


  • Chlorides
  • Ion Channels
  • Receptors, Purinergic
  • Nystatin
  • Calcimycin
  • Adenosine Triphosphate
  • Verapamil
  • Calcium