Dopamine transporter immunohistochemistry in median eminence, amygdala, and other areas of the rat brain.

In an extension of our previous work, an antibody directed against a peptide from the N-terminal region of DAT was used to localize specific dopamine transporter immunoreactivity (DAT-IR) in several regions of rat brain. Apparent axons and varicosities were found in the zona incerta, external layer of the median eminence, various nuclei of the amygdala, the cortex-amygdala transition zone, and in periglomerular regions in the olfactory bulb. Apparent stained neuronal perikarya and dendrites were observed in the arcuate nucleus and olfactory bulb. These regions are known to have dopaminergic neurons and innervations, although there was not a perfect correspondence between DAT-IR and the known distribution of dopaminergic neurons. A possible explanation is that different dopamine containing cell groups express different levels of DAT mRNA and protein, as we have previously shown. Also in the tuberoinfundibular neurons, for example, DAT-IR was preferentially localized to distal axons in the median eminence, suggesting intracellular compartmentation.