Figure 6.

Differing effects of intrathecal (i.t.) application of morphine on responses to noxious pinching. A, Example of a pruriceptive VTT neuron's baseline response to pinching and similar response in the presence of morphine. B, Mean histograms of responses of pruriceptive cells (n = 10) to pinching under three conditions. C, Example of a nociceptive VTT neuron's baseline response to pinching and greatly reduced response in the presence of morphine. D, Mean histogram of responses of nociceptive cells (n = 10) to pinching under three conditions. E, Normalized mean discharge rates during pinching for nociceptive cells during four conditions. F, Effects of i.t. application of vehicle and morphine on normalized mean responses of nociceptive and pruriceptive VTT neurons to pinching.