Figure 7
CGRP Spinal Cord Expression in NGF-treated rats. CGRP-IR increases in lumbosacral spinal cord with exogenous NGF treatment. CGRP-IR in the L6 (A-B) and S1 (D-E) spinal segment in control (A, D) and NGF-treated (B, E) rats. A, D. Fluorescence photographs showing CGRP-IR in the L6 (A) and S1 (D) spinal segment of control (saline) + bladder distention. B, E. Fluorescence photographs showing CGRP-IR in the L6 (B) and S1 (E) spinal segment with NGF treatment + bladder distention. Increased density of CGRP-IR was observed in the medial (MDH) to lateral (LDH) extent of the superficial laminae (I-II) of the dorsal horn (DH) with NGF treatment in L6 (C) and S1 (F) segments. Changes in CGRP-IR in other spinal cord regions were more dramatic in the S1 spinal segment. Increased CGRP-IR was present in a fiber bundle extending from Lissauer's tract in lamina I along the lateral edge of the DH to the region of the sacral parasympathetic nucleus (SPN) (lateral collateral pathway of Lissauer, LCP) in the S1 segment (F). Although this fiber bundle was present in control tissue sections, the staining was less intense (D) and was less frequently observed in transverse sections compared to NGF treatment (E). Faint CGRP-IR was present in the region of the SPN in control sections (A, D). With NGF treatment, CGRP-IR in the SPN region also increased in the S1 segment. Increased CGRP-IR was also present in the dorsal commissure (DCM) with NGF treatment (D, E, F). Summary bar graphs of CGRP-IR optical density (O.D.) as measured in specific regions of the L6-S1 spinal cord (C, F). Calibration bar represents 125 μm. *, p ≤ 0.01.