Figure 4.

The paclitaxel-induced increase in NCX activity in thigh neurons is KB-R7943 resistant and SEA0400 sensitive. A) Ca²⁺ transients evoked with 4s application of 30 mM K⁺ in putative nociceptive neurons labeled from the thigh skin from vehicle-treated (left) and paclitaxel-treated (right) rats before (dotted traces) and after (solid traces) block of NCX with KB-R7943 (100 nM). B) Putative nociceptive neurons from vehicle (V) and paclitaxel (P) treated rats retrogradely labeled from the glabrous skin (Glabrous) and the inner thigh skin (Thigh), were analyzed as a function of whether or not KB-R7943 was associated with an increase in the duration of the evoked Ca²⁺. The proportion of KB-R7943-responsive neurons in each group is plotted. The total number of neurons studied in each group is indicated in parenthesis. C) KB-R7943-induced increase in the duration of the Ca²⁺ transient evoked with a 4 s application of 30 mM K⁺ was analyzed as a percent increase T50. Pooled data are from the KB-R7943-responsive neurons plotted in B. D) To estimate the fraction of total NCX activity sensitive to KB-R7943, increase in T50 associated with KB-R7943 was analyzed as a percentage of the average increase in T50 in response to Li⁺ (%Li⁺-induced ΔT50). Pooled data from C analyzed in this way are plotted in D). E) Ca²⁺ transients evoked with 4s application of 30 mM K⁺ in putative nociceptive neurons labeled from the thigh skin from vehicle-treated (left), and paclitaxel-treated (right) rats before (dotted traces) and after (solid traces) application of the putative NCX1 preferring blocker SEA0400. F) The proportion of SEA0400-responsive thigh neurons from paclitaxel (P) treated rats was significantly greater than that in neurons from vehicle (V) treated rats. The number in parentheses is the total number of neurons studied from each group.* is p < 0.05, ** is p < 0.01.