Repeated Isoflurane Exposures Impair Long-Term Potentiation and Increase Basal GABAergic Activity in the Basolateral Amygdala

Figure 2

Effects of repeated isoflurane exposures on LTP in the BLA. Field potentials were evoked in the BLA by stimulation of the external capsule. (a), (b), and (c) show the time course of changes in the amplitude of the responses after high-frequency stimulation (HFS), in control rats (black circles) and rats exposed to three sessions of 1 h isoflurane anesthesia, with a 48 h interval between sessions (open circles); LTP studies were performed at 1 day (a), 1 week (b), and 1 month (c) after the last exposure. The amplitudes of three responses recorded in each min (stimulation at 0.05 Hz) were averaged, and each data point on the plot is the mean and standard error of these averages, from 9 to 13 slices. Traces over the plots are examples from a control rat and from isoflurane-exposed rats; the superimposed field potentials are a baseline response and a response at 50 to 60 min after HFS (each trace is the average of 10 to 20 sweeps). The data are summarized in (d), for the amplitude of the field potentials during the 50 to 60 min time-window after HFS, expressed as % of the control amplitude. , for the controls, for the 1-day group, for the 1-week group, and for the 1-month group.

(a)

(b)

(c)

(d)