Figure 2.

Distribution of diazepam-insensitive sites and induction of LTP. (a) Autoradiographic distribution of benzodiazepine binding sites in parasagital brain sections of wild-type and α₅(H105R) mice. (Left) Labeling of both diazepam-sensitive and -insensitive GABA_A receptors by incubation with 20 nM [³H]Ro 15–4513. (Right) Incubation with the radioligand in the presence of 10 μM diazepam (labeling of diazepam-insensitive receptors). Nonspecific binding was assessed in the presence of 10 μM flumazenil. (b) Schaffer collateral LTP in wild-type (●) and α₅(H105R) mice (▵). After 10 min of baseline recording in hippocampal slices, 20 pulses were given at 100 Hz repeated four times with a 20-s interval for a total of 80 stimuli. The slope (20–80%) of the field excitatory postsynaptic potential was measured and normalized to baseline. The results are given as mean ± SE as percentage of baseline. There was no significant difference in the potentiation throughout the time course of the experiment.