Figure 3.

Comparison of the localization of cells labeled for δOR in the rat lumbar (L4-5) spinal cord. A, B, Immunohistochemical labeling of δOR (Fig. 5A) [Cahill et al. (2001a), reprinted with permission] (A) and δOR mRNA expression (B), as revealed by in situ hybridization, concur in demonstrating the presence of this receptor in neurons distributed throughout the gray matter of the spinal cord. C, Schematic representation of the distribution of Fluo-DLT-labeled perikaryal profiles in the lumbar spinal cord (L5) (Paxinos and Watson, 1986) of control, non-pretreated rats. The number of filled circles within each lamina represents the average number of Fluo-DLT-labeled cell body profiles per section. D, Comparison of the estimated number of cross-sectioned neurons counted by the three techniques in the dorsal (laminas III-VI) and ventral (VII-IX) horns. Fluo-DLT, immunuhistochemical (IHC)- and in situ hybridization (ISH)-labeled profiles were counted as described in Materials and Methods. Because these three techniques used sections of different thickness, counts were corrected to 20 μm according to the following formula: [(counts × 20)/(section thickness in micrometers)].