Highest concentrations (>500 amol/mm2) |
External plexiform layer of the olfactory bulb |
Nucleus accumbens |
Olfactory tubercule |
Intermediate concentrations (181–313 amol/mm2) |
Layers V–VI of the cerebral cortex |
Medial nucleus of the amygdala |
Corpus striatum |
Basolateral nucleus of the amygdala |
Cortical nucleus of the amygdala |
Layers I–II of the cerebral cortex |
Lateral nucleus of the amygdala |
Layers III–IV of the cerebral cortex |
Granular layer of the olfactory bulb |
Low concentrations (<100 amol/mm2) |
Hippocampus pyramidal layer |
Inferior colliculus |
Central nucleus of the amygdala |
Habenula |
Globus pallidus |
Hypothalamus |
Glomerular layer of the olfactory bulb |
Accessory olfactory bulb |
Substantia gelatinosa of the spinal cord |
Stria terminalis |
Central gray |
Superior collicus |
Substantia nigra |
Thalamus |
Lateral geniculate bodies |
Ventral gray of the spinal cord |
These data are taken from Mansour et al., 1988, 1995, and Sharif and Hughes, 1989. Tissues are listed in decending order of receptor density. For δ-opioid receptor density levels in the mouse brain, seeKitchen et al. (1997).