Figure 3.

Resting and evoked Ca²⁺ transients from putative nociceptive DRG neurons defined by target of innervation from control (naïve and vehicle treated) rats or rats treated with paclitaxel. A) Typical high K⁺ (30 mM) evoked Ca²⁺ transients from putative nociceptive DRG neurons innervating glabrous skin of the hindpaw from rats treated with either vehicle or paclitaxel. Pooled data were analyzed as in Figure 2. B) While the main effect of target of innervation on resting [Ca²⁺]_i, persisted, there was no detectable influence of paclitaxel on this parameter. C) There was also no detectable influence of paclitaxel on the magnitude of the evoked Ca²⁺ transient. D) However, there was a significant interaction between target of innervation and paclitaxel treatment on the duration of the evoked Ca²⁺ transient. Post-hoc analysis confirmed that the decrease in the duration of the evoked Ca²⁺ transient in both glabrous and hindpaw hairy skin (Dorsal) neurons were significant. To determine whether there was a difference between groups defined by target of innervation with respect to the size of the paclitaxel-induced decrease in duration, data from paclitaxel treated neurons were analyzed as a percent change from control. These data (E), were analyzed with a one-way ANOVA, which confirmed that the difference between groups was significant (p < 0.01). Post-hoc analysis confirmed the decrease in the glabrous neurons was significantly greater than that in neurons from either the dorsal hindpaw or thigh. Numbers of neurons in each group are control glabrous = 91, paclitaxel glabrous = 44, control dorsal = 50, paclitaxel dorsal = 33, control thigh = 62, paclitaxel thigh = 47; * p<0.05).