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Selective subregional dopamine depletions in the rat caudate‐putamen following nigrostriatal lesions
Author(s) -
Pehek Elizabeth A.,
Crock Ronald,
Yamamoto Bryan K.
Publication year - 1992
Publication title -
synapse
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.809
H-Index - 106
eISSN - 1098-2396
pISSN - 0887-4476
DOI - 10.1002/syn.890100406
Subject(s) - substantia nigra , dopamine , putamen , caudate nucleus , nigrostriatal pathway , nucleus accumbens , neurochemical , striatum , chemistry , basal ganglia , medicine , neuroscience , endocrinology , biology , dopaminergic , central nervous system
Abstract Previous work has demonstrated a complex neurochemical and neuroanantomical heterogeneity of the striatum in normal brains. The present research investigated whether the heterogeneous distribution of dopamine would be altered following unilateral injections of the neurotoxin 6‐hydroxydopamine into the substantia nigra of the rat. Four weeks following injection, the nucleus accumbens and subregions of the caudate‐putamen and substantia nigra were dissected and analyzed by HPLC with electrochemical detection for dopamine, 5‐hydroxytryptamine, and their respective metabolites. Levels of dopamine and its metabolites in the anterodrsolateral caudateputamen were depleted more than medial, posterior, and ventral, striatal areas in partially lesioned animals (<90% dopamine depletion). This resulted in an alteration of striatal heterogeneity such that a mediolateral gradient of dopamine tissue content was now superimposed on the normal rostrocaudal gradient observed in controls. Paralleling these findings, dopamine was more depleted in the lateral, as opposed to the medial, substantia nigra. These results indicate that the nigrostriatal dopamine system degenerates in a heterogeneous fashion following 6‐hydroxydopamine administration. It is speculated that the differential loss of dopamine neurons observed in the nigra of Parkinson's patients may be due to a differential sensitivity to toxins within the nigra.