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Increase in Striatal [ 3 H]Muscimol Binding Following Intrastriatal Injection of Kainic Acid: A Denervation Supersensitivity Phenomenon
Author(s) -
Kuriyama Kinya,
Kurihara Etsuo,
Ito Yoshihisa,
Yoneda Yukio
Publication year - 1980
Publication title -
journal of neurochemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.75
H-Index - 229
eISSN - 1471-4159
pISSN - 0022-3042
DOI - 10.1111/j.1471-4159.1980.tb06270.x
Subject(s) - muscimol , kainic acid , microinjection , chemistry , striatum , globus pallidus , endocrinology , gabaa receptor , medicine , binding site , agonist , cerebellum , receptor , biochemistry , basal ganglia , biology , central nervous system , dopamine , glutamate receptor
The effect of intrastriatal microinjection of kainic acid (KA) on specific binding of [ 3 H]muscimol to the particulate fractions obtained from corpus striatum (CS), globus pallidus (GP), substantia nigra (SN), and cerebral cortex (CC) was examined. Seven days after the unilateral intrastriatal microinjection of KA, the amount of specifically bound [ 3 H]muscimol was significantly increased at the injected site, whereas no significant alteration of [ 3 H]muscimol binding was found in GP, SN, or CC. Scatchard analysis of striatal binding revealed that microinjection of KA significantly increased the affinity ( K D ) of GABA receptors on the injected (lesioned) side of the CS without affecting the total number of binding sites (B max ) therein. This significant increase in [ 3 H]muscimol binding, however, was eliminated by pretreating particulate fractions from the CS with Triton X‐100, a non‐ionic detergent. No statistically significant difference in amounts of [ 3 H]muscimol binding was detected when the preparations from the KA‐treated and non‐treated CS were preincubated with 0.05% Triton X‐100, respectively. Scatchard analysis using CS preparations treated with 0.05% Triton X‐100 revealed that the affinity of the GABA receptor was increased by treatment with Triton X‐100, while the total number of binding sites (B max ) was unchanged by this treatment. These results suggest that neuronal degeneration produced by KA in vivo and pretreatment of particulate preparations with Triton X‐100 in vitro may increase the amount of specifically bound [ 3 H]muscimol to CS preparations by a similar molecular mechanism.