Figure 6
NPS effects on individual amygdala neurons. Extracellular single unit recordings of individual amygdala neurons in the central nucleus (CeA). Oscilloscope traces show original recordings of action potentials (spikes). Peristimulus rate histograms show spikes/s; bin width 1 s. Horizontal lines indicate innocuous and noxious test stimuli (compression of the knee joint; see Methods). (A) Stereotaxic administration of NPS (100 μM, concentration in microdialysis probe; 20 min) into the ITC area did not change the activity of a CeA neuron in a normal rat. (B) Stereotaxic administration of NPS into the ITC inhibited the activity of another CeA neuron in a rat with arthritis (6 h postinduction). (C) Coapplication of a selective NPSR antagonist ([D-Cys(tBu)5]NPS, 1 mM, concentration in microdialysis probe; 20 min) into the ITC area blocked the effect of NPS in another CeA neuron recorded in an arthritic rat (6 h postinduction).