silver grains indicative of the binding of labeled [ 3h ] diprenorphine are discretely localized in numerous areas of the brain with very high densities in the locus coeruleus , the substantia gelatinosa of the spinal cord , and in clusters within the caudate-putamen , amygdala , and parts of the periventricular gray matter .
C0006104
brain
C0023951
locus coeruleus