title: Characterization of the responses of Purkinje cells to neurotrophin treatment.
abstract: The ability of the neurotrophins nerve growth factor (NGF), brain-derived neurotrophic factor (BDNF), neurotrophin-3 (NT-3), and neurotrophin-4/5 (NT-4/5) to promote neuronal survival and phenotypic differentiation was examined in dissociated cultures from embryonic day 16 rat cerebellum. BDNF treatment increased the survival of neuron-specific enolase-immunopositve cells by 250 and 400% after 8 and 10 days in culture, respectively. A subpopulation of these neurons, the Purkinje cells, identified by calbindin staining, was increased to an equivalent extent, approximately 200%, following BDNF, NT-4/5 or NT-3 treatment. The number of GABAergic neurons, identified by GABA immunoreactivity, was greatly increased by treatment with BDNF (470%) and moderately by NT-4/5 (46%), whereas NT-3 was without effect. NGF failed to increase the number of either Purkinje cells or GABAergic neurons. Addition of BDNF within 48 h of cell plating was required to obtain a maximal increase in Purkinje cell number after 8 days. In contrast, the NT-3 responses were nearly equivalent even if treatment was delayed for 96 h after plating. BDNF, NT-4/5, and NT-3, but not NGF, induced the rapid expression of the immediate early gene c-fos. Immunocytochemical double-labeling with antibodies to c-fos and calbindin was used to identify Purkinje cells that responded to neurotrophin treatment by induction of c-fos. After 4 days in vitro, both BDNF and NT-3 induced the formation of c-fos protein in calbindin-immunopositive neurons, whereas NT-4/5 did not. The latter results suggest that although BDNF and NT-4/5 have been shown to act through a common receptor, TrkB, it appears that the effects of BDNF and NT4/5 are not identical.
authors.affiliation: Regeneron Pharmaceuticals, Tarrytown, New York, USA.
authors.forename: L
authors.initials: L
authors.lastname: Lärkfors
authors.forename: R M
authors.initials: RM
authors.lastname: Lindsay
authors.forename: R F
authors.initials: RF
authors.lastname: Alderson
mesh_terms: D000818:Animals; D000918:Antibody Specificity; D015152:Blotting, Northern; D019208:Brain-Derived Neurotrophic Factor; D064026:Calbindins; D002452:Cell Count / Q000187:drug effects; D002478:Cells, Cultured / Q000166:cytology / Q000187:drug effects; D002531:Cerebellum / Q000166:cytology; D005260:Female; D006801:Humans; D007150:Immunohistochemistry; D009414:Nerve Growth Factors / Q000494:pharmacology*; D009419:Nerve Tissue Proteins / Q000494:pharmacology*; D009474:Neurons / Q000737:chemistry / Q000166:cytology / Q000187:drug effects; D020933:Neurotrophin 3; D011247:Pregnancy; D016760:Proto-Oncogene Proteins c-fos / Q000032:analysis / Q000187:drug effects / Q000276:immunology; D011689:Purkinje Cells / Q000737:chemistry / Q000166:cytology / Q000187:drug effects*; D012333:RNA, Messenger / Q000032:analysis; D051381:Rats; D017207:Rats, Sprague-Dawley; D020794:Receptor Protein-Tyrosine Kinases / Q000235:genetics; D020801:Receptor, Ciliary Neurotrophic Factor; D020812:Receptor, trkC; D017475:Receptors, Nerve Growth Factor / Q000235:genetics; D064030:S100 Calcium Binding Protein G / Q000032:analysis / Q000187:drug effects / Q000276:immunology; D013997:Time Factors; D005680:gamma-Aminobutyric Acid / Q000502:physiology
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D064026:Calbindins; D009414:Nerve Growth Factors; D009419:Nerve Tissue Proteins; D020933:Neurotrophin 3; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D020801:Receptor, Ciliary Neurotrophic Factor; D017475:Receptors, Nerve Growth Factor; D064030:S100 Calcium Binding Protein G; C071951:neurotrophin 5; D005680:gamma-Aminobutyric Acid; D020794:Receptor Protein-Tyrosine Kinases; D020812:Receptor, trkC; C073922:neurotrophin 4