title: Dynamics of Ca(2+) and Na(+) in the dendrites of mouse cerebellar Purkinje cells evoked by parallel fibre stimulation.
abstract: Ca2+ and Na+ play important roles in neurons, such as in synaptic plasticity. Their concentrations in neurons change dynamically in response to synaptic inputs, but their kinetics have not been compared directly. Here, we show the mechanisms and dynamics of Ca2+ and Na+ transients by simultaneous monitoring in Purkinje cell dendrites in mouse cerebellar slices. High frequency parallel fibre stimulation (50 Hz, 3-50-times) depolarized Purkinje cells, and Ca2+ transients were observed at the anatomically expected sites. The magnitude of the Ca2+ transients increased linearly with increasing numbers of parallel fibre inputs. With 50 stimuli, Ca2+ transients lasted for seconds, and the peak [Ca2+] reached approximately 100 microm, which was much higher than that reported previously, although it was still confined to a part of the dendrite. In contrast, Na+ transients were sustained for tens of seconds and diffused away from the stimulated site. Pharmacological interventions revealed that Na+ influx through alpha-amino-3-hydroxy-5-methyl-4-isoxazolepropionic acid (AMPA) receptors and Ca2+ influx through P-type Ca channels were essential players, that AMPA receptors did not operate as a Ca2+ influx pathway and that Ca2+ release from intracellular stores through inositol trisphosphate receptors or ryanodine receptors did not contribute greatly to the large Ca2+ transients.
authors.affiliation: Laboratory for Developmental Neurobiology, Brain Science Institute, RIKEN, 2-1 Hirosawa, Wako, Saitama, 351-0198 Japan.
authors.forename: Akinori
authors.initials: A
authors.lastname: Kuruma
authors.forename: Takafumi
authors.initials: T
authors.lastname: Inoue
authors.forename: Katsuhiko
authors.initials: K
authors.lastname: Mikoshiba
mesh_terms: D018750:6-Cyano-7-nitroquinoxaline-2,3-dione / Q000494:pharmacology; D000779:Anesthetics, Local / Q000494:pharmacology; D000818:Animals; D000831:Animals, Newborn; D001896:Boron Compounds / Q000494:pharmacology; D002118:Calcium / Q000378:metabolism*; D002121:Calcium Channel Blockers / Q000494:pharmacology; D002478:Cells, Cultured; D002531:Cerebellum / Q000166:cytology* / Q000378:metabolism; D003712:Dendrites / Q000378:metabolism*; D004307:Dose-Response Relationship, Radiation; D004558:Electric Stimulation; D018691:Excitatory Amino Acid Antagonists / Q000494:pharmacology; D018846:Excitatory Amino Acids / Q000494:pharmacology; D005260:Female; D005456:Fluorescent Dyes / Q000378:metabolism; D018698:Glutamic Acid / Q000494:pharmacology; D005998:Glycine / Q000031:analogs & derivatives* / Q000494:pharmacology; D066298:In Vitro Techniques; D007478:Iontophoresis; D008297:Male; D051379:Mice; D018408:Patch-Clamp Techniques; D011689:Purkinje Cells / Q000378:metabolism*; D012433:Ryanodine / Q000494:pharmacology; D012964:Sodium / Q000378:metabolism*; D013268:Stimulation, Chemical; D013779:Tetrodotoxin / Q000494:pharmacology; D013997:Time Factors; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid / Q000494:pharmacology; D020866:omega-Conotoxin GVIA / Q000494:pharmacology
chemical_list: D000779:Anesthetics, Local; D001896:Boron Compounds; D002121:Calcium Channel Blockers; D018691:Excitatory Amino Acid Antagonists; D018846:Excitatory Amino Acids; D005456:Fluorescent Dyes; C474696:methyl-(4-carboxyphenyl)glycine; D012433:Ryanodine; D018698:Glutamic Acid; D013779:Tetrodotoxin; D018750:6-Cyano-7-nitroquinoxaline-2,3-dione; D018350:alpha-Amino-3-hydroxy-5-methyl-4-isoxazolepropionic Acid; D020866:omega-Conotoxin GVIA; D012964:Sodium; C109986:2-aminoethoxydiphenyl borate; D002118:Calcium; D005998:Glycine