Comparison of Cannabinoid CB1 Receptor Binding in Adolescent and Adult Rats: A Positron Emission Tomography Study Using [18F]MK-9470
Figure 4
(a) In vitro autoradiographies of total [18F]MK-9470 binding intensity in coronal sections in an adolescent and an adult rat brain. The atlas of Paxinos and Watson [52] serves as a visual anatomical reference of the 11 brain regions analysed. (b) Histograms of the in vitro specific binding intensities of [18F]MK-9470 (fmoles/mg TE ± SEM) in the adolescent compared to the adult rat brain. Eleven regions of interest were analysed and assessed for statistical significant difference between adolescence and adulthood with two-way ANOVA (age × region) followed by LSD post hoc tests (*; **). Statistical analysis revealed a significant main effect (#) of age with adults having higher CB1R densities than adolescents. The frontal cortex, the cortex, the hippocampus, and the cerebellum showed a statistically significant increase in adults compared to adolescence in the post hoc analysis. Abbreviations: Striat: striatum; Frtl Cx: frontal cortex; Hipp: hippocampus; Thal: thalamus; Hypothal: hypothalamus; Amyg: amygdala; Sup Coll: superior colliculus; Cereb: cerebellum.
