Fig. 2.
The effect of synaptic activity on EPSPs, RMP and Gin in mutants lacking functional Drosophila small-conductance Ca2+-dependent K+ (dSK) channels. The CS data from Fig. 1 have been added for comparison. A: Western blot of CS larval brain (B) and muscle (M) tissue (left) and dSK− larval brain and muscle tissue (right) probed with an antibody specific to the dSK channel. The band seen in CS is missing in dSK−. B: for a dSK− larvae, the EPSPs during 20-Hz stimulation (every other EPSP) and I injection before (Initial) and at the end (Final) of stimulation are shown. There was no change in the EPSP peak or amplitude and no increase in Gin. Calibration for I injection: V = 20 mV, 400 ms; I = 5 nA, 400 ms. C: combined data show that, during 20-Hz stimulation, there was no significant change in the EPSP peak for dSK− (n = 7), 24B/dSKDN (dSKDN) (n = 5) and dSKDN 1.5 Ca (n = 6) larvae. This contrasts with the results from CS larvae taken from Fig. 1. All experiments were performed in HL3 (1.0 mM Ca2+), except for dSKDN 1.5 Ca, which used HL3.1 with 1.5 mM Ca2+. D: combined data for dSK−, dSKDN, and dSKDN 1.5 Ca2+ larvae showed that there was no significant change in EPSP amplitude, RMP or Gin as a result of 20-Hz stimulation. This differed from the previous results obtained from CS larvae. Values are means ± SE. ***P < 0.001, paired t-test.