title: Changes induced by natural scrapie in the calretinin-immunopositive cells and fibres of the sheep cerebellar cortex.
abstract: Calretinin (CR)-immunopositive cells and fibres in the cerebellar cortex (vermal archicerebellum and neocerebellum) of scrapie-affected, ARQ/ARQ, Rasa Aragonesa breed sheep were studied in comparison with healthy, young and aged, ARQ/ARQ, Rasa Aragonesa animals and with Manchega breed sheep. The scrapie-affected sheep showed signs of both cellular involution and hypertrophic/hyperimmunoreactive responses in all neuronal subtypes; the distribution of the neuronal subtypes in the archi- and neocerebellum, however, did not change compared with controls. The results suggest that the different CR expression and/or CR content of cerebellar cortical neurons in scrapie-affected sheep are more related to their specific functions than any neuroprotective response. The reduction in the cell density of some CR-immunopositive neuronal subsets (i.e. unipolar brush cells) is contradictory to the supposed neuroprotective role of the calcium binding protein CR. However, the hyperimmunoreactivity of many CR-immunopositive neuronal subsets (e.g. the Purkinje cells) suggests the involvement of an over-expression of CR (transitory or restricted to selected neurons) as an adaptative mechanism to fight against the neurodegeneration caused by this prion disease. The changes in the number of immunopositive cells and the hypertrophic/hyperimmunoreactive response seen in scrapie-affected and aged sheep suggests that some different and some similar mechanisms are at work in this disease and aging.
authors: Instituto Cajal, CSIC, Avenida Dr. Arce 37, Madrid, Spain. atoledano@cajal.csic.es
authors: Adolfo
authors: A
authors: Toledano
authors: María-Isabel
authors: MI
authors: Alvarez
authors: Eva
authors: E
authors: Monleón
authors: Adolfo
authors: A
authors: Toledano-Díaz
authors: Juan-José
authors: JJ
authors: Badiola
authors: Marta
authors: M
authors: Monzón
mesh_terms: D000818:Animals; D064032:Calbindin 2; D064026:Calbindins; D002525:Cerebellar Cortex / Q000378:metabolism* / Q000473:pathology*; D005904:Glial Fibrillary Acidic Protein / Q000378:metabolism; D007150:Immunohistochemistry; D009412:Nerve Fibers / Q000378:metabolism* / Q000473:pathology*; D009415:Nerve Net / Q000378:metabolism / Q000473:pathology; D009474:Neurons / Q000378:metabolism* / Q000473:pathology*; D018620:PrPSc Proteins / Q000378:metabolism; D011689:Purkinje Cells / Q000378:metabolism; D064030:S100 Calcium Binding Protein G / Q000378:metabolism*; D012608:Scrapie / Q000378:metabolism* / Q000473:pathology*; D012756:Sheep
chemical_list: D064032:Calbindin 2; D064026:Calbindins; D005904:Glial Fibrillary Acidic Protein; D018620:PrPSc Proteins; D064030:S100 Calcium Binding Protein G