Fig. 3.

GABAergic inhibitory synaptic currents in the central amygdala are not blocked by low doses of bicuculline or picrotoxin. A, Synaptic currents in response to local electrical stimulation in the presence of blockers of glutamatergic receptors (see Materials and Methods) recorded at membrane potentials of −80, −60, −40, −20, 0, and 10 mV using low-chloride internal solution. B, Normalized current–voltage relationships for synaptic currents recorded using low-chloride (closed circles) (n = 4) and high-chloride internal solutions (open squares) (n = 2). The reversal potential in low-chloride internal was −52 mV, whereas in high-internal chloride it was 0 mV. C, Average CeL IPSCs recorded in control, in 10 μm bicuculline, and in 100 μm bicuculline. The IPSC was blocked to 67 ± 3% of control by 10 μm and 87 ± 3% in 100 μm BIC. D, IPSCs recorded in control, in 25 μm picrotoxin (PTX), and 100 μm PTX. IPSC amplitude was blocked by 64 ± 0% in 25 μm PTX. E, Summary of effects of antagonists bicuculline and picrotoxin on IPSC peak amplitude recorded from CeL neurons (filled columns) or from CA1 pyramidal neurons (open columns) (n= 5, 3, 3, 7, 5, and 4, respectively).