Cb2 expression and function in normal spleen and thymus.

(A) RNase protection on 10 μg total mouse mRNA isolated from several organs. The protected fragments were 249 nucleotides (exon-1B/exon-2Cb2 mRNA-protected) or 148 nucleotides (exon-2Cb2 mRNA-protected, representing exon-1A/exon-2). AGAPDH probe was used for normalization of the signals. (B) Receptor density (femtomoles per 10⁶ cells) on spleen cells and thymocytes was assessed by measuring specific binding of [³H]CP55940 (1 nM) (see “Materials and methods”). (C) Effect of Cb1-specific antagonist SR141716 or Cb2-specific antagonist SR144528 on spontaneous or 2-AG–induced migration of spleen cells. Antagonists and 2-AG were placed in the wells as indicated under the figure.Y-axis shows percentage of migration from an input of 2 × 10⁵ spleen cells. (D) Immunophenotyping of 2-AG–induced migrated spleen cells versus spontaneous spleen-migrated cells using flow cytometry.