Regioal distribution of immunoreactive neurotension in monkey brain.

The regional distribution of immunoreactive neurotensin (IRNT) in 66 different areas of the monkey brain and spinal cord was studied by radioimmunoassay using specific rabbit antisera to synthetic neurotensin. Each area was found to contain IRNT in uneven concentrations. Highest concentrations were present in the hypothalamic areas and the interpeduncular nucleus, values reaching around 80 pg IRNT/mg wet tissue weight. The habenula, subthalamus and preoptic area were also rich in IRNT. A relatively selective distribution of IRNT was found in the thalamic regions. Low values were obtained in the cerebral and cerebellar cortex, striatum, substantia nigra and white matter areas. Among the fiber bundle studied, the olfactory tract contained a significant amount of IRNT. The present finding of a selective distribution of IRNT suggests a specific neuronal action of neurotensin in primate central nervous system.