Alterations in regional brain concentrations of neurotensin and bombesin in Parkinson's disease.

Frozen samples of postmortem human brain tissue from patients with Parkinson's disease (n = 25) and control patients who died without neurological disease (n = 25) were assayed for neurotensin and bombesin by specific radioimmunoassay. Twelve brain regions were examined: substantia nigra, ventral tegmental area, periaqueductal gray matter, caudate nucleus, putamen, globus pallidus, amygdala, hippocampus, nucleus accumbens, frontal cortex, cingulate cortex, and entorhinal cortex. In patients with Parkinson's disease, the concentration of bombesin was significantly decreased in the caudate nucleus and globus pallidus, and the concentration of neurotensin was significantly reduced in the hippocampus. The concentration of neither peptide was significantly altered in the substantia nigra or ventral tegmental area, two regions known to exhibit reductions in other neurotransmitter substances.