Figure 4.

Histograms showing the effects of amiloride (5.0 μg kg⁻¹) on the responses of a group III afferent (conduction velocity, 14.4 m s⁻¹) to lactic acid injection (0.5 ml; 24 mm) to tendon stretch and to static contraction Before indicates the control response before injection of amiloride; 30 and 60 min indicate the responses of the group III afferent to the three stimuli 30 and 60 min after amiloride was injected. Arrows signify the injection of lactic acid. Horizontal filled bar represents the 60 s period of time that either the calcaneal tendon was stretched or the triceps surae muscles were contracted. Intervals between vertical tick marks on the horizontal axes represent 10 s. A sample of the action potential counted is shown as an inset in the far left panels.