Figure 4

Acute neck muscle inflammation does not alter action potential discharge properties . A. Dorsal horn neurons can be classified by the temporal features of their action potential discharge. We have previously described five AP discharge patterns under in vitro [16] and in vivo conditions [15], and also across the lumbar, thoracic and cervical spinal cord in adult mice [17]. Traces show representative examples of each AP discharge pattern (Tonic Firing - TF, Initial Bursting - IB, Delayed Firing - DF, Single Spiking - SS, and Reluctant Firing RF) recorded from control (left), sham (middle), and carrageenan-injected animals (right). Horizontal bars denote −50 mV membrane potential. B. The incidence of the five AP discharge patterns was similar in control, sham, and carrageenan-injected animals.