Fig. 6

Upregulation of the expression of CGRP-like IR in vivo in DRG neurons and CGRP release in vitro from DRG neurons. a. Proportions of CGRP-positive DRG neurons in the contralateral (c) and ipsilateral (i, side of inflammation) lumbar DRGs in naïve control wild-type (WT) mice (n = 5), immunized WT mice (n = 4), WT mice at 3 days of AIA (acute, n = 4) and WT mice at 21 days of AIA (chronic, n = 4). b. Proportions of CGRP-positive DRG neurons in the contralateral and ipsilateral lumbar DRGs in SNS-gp130^flox/flox (n = 4–6) and SNS-gp130^−/− mice (n = 5) at 3 days of AIA (acute) and at day 12 of flare-up (chronic). Significant differences occur between SNS-gp130^flox/flox and SNS-gp130^−/− mice in the “acute phase”. Values are mean ± SEM. c. DRG section showing CGRP-positive neurons (see arrow) after incubation with anti-CGRP antibody (left). Control staining of DRG section without anti-CGRP antibody (middle) and with CGRP (1–37)-preincubation of the anti-CGRP antibody (right). Scale bar = 10 μm. d. CGRP release in vitro from DRG neurons from WT mice. Illustrated CGRP concentrations in the supernatants show the evoked release minus the basal production in the same time. *p < 0.05, **p < 0.01 significant differences referring to “only KCl”. ^# p < 0.05, ^## p < 0.01 significant differences between different concentrations of IL-6/sIL6R. Values are mean ± SD; n = 5 each. CGRP calcitonin gene-related peptide, CGRP-like IR CGRP-like immunoreactivity, DRG dorsal root ganglion, IL-6 addition of IL-6 to the culture medium, sIL6R addition of sIL6R to the culture medium, KCl depolarization of neurons by addition of KCl (50 mmol/l) to the culture medium