306 K. Mackie
Fig. 4.Laminar CB 1 expression in cortex of three mammals. CB 1 receptors were detected with an antibody
directed against the C terminus of rat CB 1. Particularly high levels of CB 1 are found in lamina layers II, upper
III (L2/3), IV (L4), and VI (L6).Scale bar= 250 μm. (Figure provided by Tibor Harkany)
nucleus (Herkenham et al. 1991; Mailleux and Vanderhaeghen 1992; Matsuda et
al. 1993; Tsou et al. 1998a; Marsicano and Lutz 1999; Egertová and Elphick 2000).
CB 1 receptorsarealsofoundinthesupportingcellsoftheolfactoryepitheliumas
well as axon bundles of the lamina propria (M. Caillol, personal communication).
2.2
Neocortex
CB 1 receptors are densely expressed in all regions of the cortex (Herkenham et
al. 1991; Mailleux and Vanderhaeghen 1992; Matsuda et al. 1993; Glass et al. 1997;
Tsou et al. 1998a; Egertová and Elphick 2000). The variation in CB 1 expression
across cortical regions has been examined most extensively in human brain using
receptor autoradiography. Here there is variation between regions, with higher