Fig. 1.
Partial peripheral nerve injury (CCI or SNI) reduces primary afferent-evoked IPSCs in lamina II neurons.A, Representative neuron from a CCI animal with a monosynaptic Aδ-fiber-evoked EPSC but no evoked IPSC. After CCI or SNI, excitatory transmission remains intact, but the proportion of neurons with no evoked IPSC increases (Naive = 1/65; SNT = 3/32, p = 0.20;CCI = 7/41, p = 0.006;SNI = 9/32, p < 0.0001). *p < 0.05 compared with naive. B, Representative A-fiber-evoked IPSCs recorded in spinal cord slices from naive, CCI, and SNI rats. Note the reduction in amplitude and duration in CCI and SNI traces. C, Amplitude distributions for IPSCs recorded from naive rats and rats subjected to SNT, CCI, or SNI. In both partial nerve injury models, IPSC amplitudes were significantly decreased compared with the naive.Arrows indicate means. D, Frequency distributions of IPSC decay time constants (τ) from naive and nerve-injured rats, as well as pharmacologically isolated glycine (insensitive to 5–10 μm bicuculline;n = 18) and GABAA (bicuculline sensitive; n = 16) IPSCs.