title: Dendritic differentiation of cerebellar Purkinje cells is promoted by ryanodine receptors expressed by Purkinje and granule cells.
abstract: Cerebellar Purkinje cells have the most elaborate dendritic trees among neurons in the brain. We examined the roles of ryanodine receptor (RyR), an intracellular Ca(2+) release channel, in the dendrite formation of Purkinje cells using cerebellar cell cultures. In the cerebellum, Purkinje cells express RyR1 and RyR2, whereas granule cells express RyR2. When ryanodine (10 µM), a blocker of RyR, was added to the culture medium, the elongation and branching of Purkinje cell dendrites were markedly inhibited. When we transferred small interfering RNA (siRNA) against RyR1 into Purkinje cells using single-cell electroporation, dendritic branching but not elongation of the electroporated Purkinje cells was inhibited. On the other hand, transfection of RyR2 siRNA into granule cells also inhibited dendritic branching of Purkinje cells. Furthermore, ryanodine reduced the levels of brain-derived neurotrophic factor (BDNF) in the culture medium. The ryanodine-induced inhibition of dendritic differentiation was partially rescued when BDNF was exogenously added to the culture medium in addition to ryanodine. Overall, these results suggest that RyRs expressed by both Purkinje and granule cells play important roles in promoting the dendritic differentiation of Purkinje cells and that RyR2 expressed by granule cells is involved in the secretion of BDNF from granule cells.
authors.affiliation: Department of Cellular Biophysics, Graduate School of Pharmaceutical Sciences, Nagoya City University, Nagoya, 467-8603, Japan.
authors.forename: Ryo
authors.initials: R
authors.lastname: Ohashi
authors.forename: Shin-ichi
authors.initials: S
authors.lastname: Sakata
authors.forename: Asami
authors.initials: A
authors.lastname: Naito
authors.forename: Naohide
authors.initials: N
authors.lastname: Hirashima
authors.forename: Masahiko
authors.initials: M
authors.lastname: Tanaka
mesh_terms: D000818:Animals; D019208:Brain-Derived Neurotrophic Factor / Q000378:metabolism; D002118:Calcium / Q000378:metabolism; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D003712:Dendrites / Q000187:drug effects / Q000502:physiology*; D051379:Mice; D008810:Mice, Inbred C57BL; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D011689:Purkinje Cells / Q000166:cytology / Q000187:drug effects / Q000502:physiology*; D012433:Ryanodine / Q000494:pharmacology; D019837:Ryanodine Receptor Calcium Release Channel / Q000235:genetics / Q000378:metabolism*
chemical_list: D019208:Brain-Derived Neurotrophic Factor; D002121:Calcium Channel Blockers; D019837:Ryanodine Receptor Calcium Release Channel; C000592747:ryanodine receptor 1, mouse; C000592748:ryanodine receptor 2. mouse; D012433:Ryanodine; D002118:Calcium
keywords: Purkinje cell; dendrite; granule cell; ryanodine receptor; single-cell electroporation