Tyrosine hydroxylase-like immunoreactivity is distributed in the matrix compartment of normal human and Huntington's disease striatum.

Tyrosine hydroxylase-like immunoreactivity (TH-lir) was examined in the adult human neostriatum and found to be heterogeneously distributed. Comparison of TH-lir with adjacent sections stained for acetylcholinesterase (AChE) activity showed that TH-lir is confined to the AChE-rich matrix compartment. TH-lir persists within the matrix zone, which is reduced in Huntington's disease (HD), suggesting that the nigrostriatal AChE projection may contribute to the persistent AChE patch-matrix pattern in HD. Despite marked striatal atrophy, the density of TH-immunoreactive fibers and terminals remained unchanged. This represents a loss of TH-positive extrinsic afferents in HD proportionate to striatal atrophy.