EXPRESSION OF MOLECULES ASSOCIATED WITH NEURONAL PLASTICITY IN THE STRIATUM AFTER ASPIRATION AND THERMOCOAGULATORY LESIONS OF THE CEREBRAL-CORTEX IN ADULT-RATS

Like the hippocampus, the striatum receives excitatory afferents from the cerebral cortex but, in the case of the striatum, very little is k nown about the molecular events associated with plasticity after lesio ns of this pathway, Using immunohistochemical techniques, we have exam ined the effects of cortical lesions induced either by aspiration of t he frontoparietal cortex or by thermocoagulation of pial blood vessels on axonal and glial molecules associated with neuronal plasticity in the striatum, The growth associated protein GAP-43, a molecule present in axons and growth cones, decreased in the dorsolateral striatum aft er aspiration but not after thermocoagulatory lesions, In contrast, sy naptophysin, a marker of synaptic vesicles, remained unchanged in the denervated striatum after both types of lesions. Immunostaining for ba sic fibroblast growth factor (bFGF) markedly decreased in striatal ast rocytes after both lesions, despite an increased staining for glial fi brillary acidic protein (GFAP), The adhesion molecules tenascin, chond roitin sulfate proteoglycans, highly polysialylated neural cell adhesi on molecule (PSA-NCAM), and laminin did not change significantly in th e gray matter of the dorsolateral striatum after either type of lesion , These effects differed from those observed after partial denervation of the hippocampus and spinal cord, revealing marked regional differe nces in the response of axonal and glial proteins to afferent lesions, In addition, the results further indicate that cortical lesions have both similar and distinct consequences, depending on the procedure by which the lesions are induced, suggesting that cortical lesions associ ated with different types of pathology may differentially affect subco rtical structures.