Figure 4. The tarantula peptide GsMTx-4 inhibits the activation of TRPC5 by hypoosmotic stimulation.

A, whole-cell currents evoked by hypoosmotic solutions in a TRPC5 transfected cell incubated for 20 min with 5 μm GsMTx-4 before recording. B, responses to 100 μm histamine in a cell transfected with TRPC5 and H₁ receptor in the presence of GsMTx-4 and after wash out of the toxin; same preincubations as in A. C and D, I–V relationships corresponding with the time points marked in colours in A and B, respectively. E, bar graph summarizing the effect of GsMTx-4 on the percentage of cells that respond to hypoosmotic stimulation and histamine (*P < 0.05, compared with non-treated cells; Z-test). F, the increases in current of the responsive cells measured at –80 and +80 mV are summarized in the bar graph. **P < 0.01 compared with control cells for each type of stimulation (Student's t test).