Del Rey NLG, Trigo-Damas I, Obeso JA, Cavada C, Blesa J. Neuron types in the primate striatum: stereological analysis of projection neurons and interneurons in control and parkinsonian monkeys.
Neuropathol Appl Neurobiol 2022;
48:e12812. [PMID:
35274336 DOI:
10.1111/nan.12812]
[Citation(s) in RCA: 1] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Received: 08/20/2021] [Revised: 02/08/2022] [Accepted: 02/12/2022] [Indexed: 11/26/2022]
Abstract
AIMS
The striatum is mainly composed of projection neurons. It also contains interneurons, which modulate and control striatal output. The aim of the present study was to assess the percentages of projection neurons and interneuron populations in the striatum of control monkeys and of parkinsonian monkeys.
METHODS
Unbiased stereology was used to estimate the volume density of every neuron population in the caudate, putamen and ventral striatum of control monkeys and of monkeys treated with MPTP, which results in striatal dopamine depletion. The various neuron population phenotypes were identified by immunohistochemistry. All analyses were performed within the same subjects using similar processing and analysis parameters, thus allowing for reliable data comparisons.
RESULTS
In control monkeys, the projection neurons, which express the Dopamine-and-cAMP-Regulated-Phosphoprotein, 32-KDa (DARPP-32), were the most abundant: ~86% of the total neurons counted. The interneurons accounted for the remaining 14%. Among the interneurons, those expressing Calretinin were the most abundant (Cr+: ~57%; ~8% of the total striatal neurons counted), followed those expressing Parvalbumin (Pv+: ~18 %; 2.6%), Dinucleotide Phosphate-Diaphorase (NADPH+: ~13 %; 1.8%), Choline Acetyltransferase (ChAT+: ~11%; 1.5%) and Tyrosine Hydroxylase (TH+: ~0.5%; 0.1%). No significant changes in volume densities occurred in any population following dopamine depletion, except for the TH+ interneurons, which increased in parkinsonian non-symptomatic monkeys and even more in symptomatic monkeys.
CONCLUSIONS
These data are relevant for translational studies targeting specific neuron populations of the striatum. The fact that dopaminergic denervation does not cause neuron loss in any population has potential pathophysiological implications.
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