Aim: 

White adipocytes possess I_KV that may be essential for the normal proliferation and differentiation of these cells. P2 receptors have been identified in white adipocytes, but their effects on I_KV are not well known. In this work we present the actions of ATP on I_KV and on the proliferation and differentiation of these cells.

Methods: 

Adipocytes were obtained by culturing preadipocytes from rat epididymal tissue and human tissues. Ionic currents were recorded using the whole-cell configuration of the patch-clamp technique. ATP, UTP, and abMeATP (P2, P2Y and P2X agonists respectively) were added to the bath at 100 mM. Cell growth was studied using grid-embossed culture dishes that allow identifying and photographing the same area at 24 h intervals. ATP (100 mM) was added to the culture media after the first day.

Results: 

The results showed that ATP blocked the outward currents in rat and human adipocytes (80 and 48% respectively), and shifted approximately 30 mV the activation threshold of I_KV to more negative values. Similar results were obtained in presence of abMeATP but not with UTP. These results suggest that the effect of ATP on I_KV should be mediated principally by P2X receptors. ATP decreased by a 41% the current density (pA/mm²) and reduced the proliferation (30%) and differentiation (69%) of adipose cells of rats.

Conclusions: 

P2X receptors may modulate voltage-dependent potassium channels, and control the proliferation and differentiation of these cells. Thus, these receptors could have a significant role in the control of obesity.