Corticosterone-induced changes in mEPSC frequency (transiently) attenuate.

(A)Experimental design. Corticosterone (CORT, 100 nM) or its vehicle was applied for 10 min (thin horizontal arrow), followed by 50 min application of the standard recording buffer. This sequence was repeated four times. For each pulse, the mEPSC properties were recorded during the final 5 min of CORT application (bold vertical arrow) and compared with the properties recorded in the 5 min just prior to hormone application. Statistical analysis is described in the Methods section. A highly similar design was used to determine changes in GluA2 subunit properties during four pulses of CORT; for each pulse this was compared to the values observed just prior to CORT application (see Fig 2). (B) Typical mEPSC trace before, during and 10 min after the first corticosterone application, in an identified CA1 pyramidal cell. An example of a single mEPSC with higher time resolution is shown in the inset. (C) Relative change in mEPSC frequency compared to the pre-pulse baseline (= 100%) after each of four pulses of corticosterone. Data show the mean ± SEM change (n = 6 cells for each pulse). Statistically significant changes in mEPSC frequency due to application of corticosterone (compared to baseline) are indicated by * (p<0.05) or ** (p<0.01).