Morphological features, distribution and compartmental organization of the nicotinamide adenine dinucleotide phosphate reduced‐diaphorase interneurons in the human striatum

Abstract

Striatal nicotinamide adenine dinucleotide phosphate reduced-diaphorase (NADPH-d)-positive (+) cells are one of the major classes of striatal interneurons. The present study analyzes their somatodendritic morphology, distribution pattern, and compartmental organization in the caudate nucleus (CN) and putamen (Put) of nine normal human brains. The following striatal territories are examined: 1) the precommissural head of the CN; 2) the postcommissural head of the CN; 3) the body of the CN; 4) the gyrus of the CN; 5) the tail of the CN; 6) the precommissural Put; and 7) the postcommissural Put. Three morphologically distinct types of NADPH-d+ neurons were found in each of these territories. The two most common NADPH-d+ neurons displayed an ovoid or triangular perikaryon from which several thick primary dendrites emerged, although much less numerous, bipolar-shaped NADPH-d+ cells were also observed. The highest density of NADPH-d+ neurons was found in the gyrus of the CN, followed by the body of the CN, tail of the CN, postcommissural head of the CN, postcommissural Put, precommissural head of the CN, and precommissural Put. The matrix was the striatal compartment with the densest NADPH-d+ neuronal population. Some of these cells also occurred in the center and peripheral regions of the striosomes located in the head of the CN and in the Put. In the body and gyrus of the CN, the striosomes were largely devoid of these striatal interneurons. Knowledge of the density and distribution of these interneurons should advance our understanding of the organization of the normal human striatum and help to evaluate the effects of neurodegenerative processes on cell density.

Nitric Oxide Modulation of the Basal Ganglia Circuitry: Therapeutic Implication for Parkinson's Disease and Other Motor Disorders

“…Thus, at least some of the NOS reticular neurons of the human striatum have direct cortical projections, though the existence of their axon collaterals in striatal tissues close to the maternal cells also demonstrates that they influence surrounding cells [26]. Moreover, the matrix is the striatal compartment with the densest NOS neuronal population that tends to be located at the boundaries between the striosomes and the matrix, as well as at the boundaries between the core and the peripheral region of the striosomes [41]. This finding has an important functional implication, because the NOS neurons that occur at the edges between the two compartments are thought to mediate interactions between the medium spiny neurons (MSNs) of the matrix and the striosomes.…”

Striatal projections from the lateral and posterior thalamic complexes. An anterograde tracer study in the cat

“…The existence in it of discrete biochemical compartments was first shown to occur for the distribution of the enzyme AChE (Graybiel and Ragsdale 1978) and then, for a large number of neuropeptides (see references in Graybiel 1990; Haber and Gdowski 2004). Complex patterns of compartmentalization have been also described for practically all the striatal connectivity as well as for the cellular organization of the striatum (see references in Graybiel 1990;Berna´cer et al 2005).…”

Nitric Oxide Modulation of the Dopaminergic Nigrostriatal System: Focus on Nicotine Action

“…The NOS expression in the striatum has been more extensively studied (Bernácer et al 2005;Egberongbe et al 1994;Eve et al 1998;Govsa and Kayalioglu 1999;Johannes et al 2003;Leontovich et al 2004;Nisbet et al 1994;Vincent and Kimura 1992). NOS neurons are one type of the four different classes of interneurons present in the striatum, and in the human they populate the entire striatum, including the tail and head of the caudate nucleus.…”

“…Thus, at least some of the NOS reticular neurons of the human striatum have direct cortical projections, though the existence of their axon collaterals in striatal tissues close to the maternal cells also demonstrates that they influence surrounding cells (Leontovich et al 2004). Moreover, the matrix is the striatal compartment with the densest NOS neuronal population that tends to be located at the boundaries between the striosomes and the matrix, as well as at the boundaries between the core and the peripheral region of the striosomes (Bernácer et al 2005). This finding has an important functional implication, because the NOS neurons that occur at the edges between the two compartments are thought to mediate interactions between the medium spiny neurons (MSNs) of the matrix and the striosomes.…”