Figure 11.

Acute applications of antidepressants had little effect on ATP-evoked responses recorded from activated C8-B4 cells. (A) Representative traces and summary data for the effect of “test drugs” (antidepressants or IVM) on responses to ATP recorded from C8-B4 cells. The test drugs were applied at the indicated concentrations for the duration shown by the gray bar after the peak of the ATP response. None of the antidepressants produced significant block of ATP-evoked responses, whereas IVM potentiated the currents when applied with the same protocol (see Data analysis in Materials and methods for how the percent block and potentiation were calculated). (B) Experiments from activated C8-B4 cells when test drugs (antidepressants or IVM at the concentrations shown) were applied in between 100-µM ATP applications after gathering two control responses. Using this protocol, we found that IVM caused a large potentiation of the ATP-evoked currents, but the antidepressants failed to cause substantial block of the responses. However, paroxetine did cause an ∼25% reduction in the ATP-evoked current (see Results). All of the ATP-evoked currents were measured at a holding voltage of −60 mV.