Regional and subcellular distributions of brain neurotensin.

The regional and subcellular distribution of neurotensin were determined using a newly developed radioimmunoassay for this central nervous system tridecapeptide. Neurotensin immunoreactivity in calf brain is high in the hypothalamus and basal ganglia, unevenly distributed through the cerebral cortex, and low in cerebellar cortex and cerebral white matter. Subcellular fractionation of rat hypothalamus reveals a strong association of neurotensin immunoreactivity with synaptosomal and microsomal fractions. These data, taken along with previously described high affinity selective brain membrane receptor binding, are consistent with a neurotransmitter candidate role for neurotensin in the brain.