title: Calmodulin-dependent regulation of neurotransmitter release differs in subsets of neuronal cells.
abstract: The purpose of this study was to determine whether calmodulin (CaM) plays a role in neurotransmitter release by examining the effect that ophiobolin A (OBA), a CaM antagonist, on neurotransmitter release from clonal rat pheochromocytoma PC12 cells, primary cortical neurons, and primary cerebellar granule cells. OBA inhibited Ca²⁺/CaM-dependent phosphorylation of cAMP response element binding protein in all cell types tested. Moreover, Ca²⁺-dependent release of dopamine and acetylcholine from PC12 cells were remarkably reduced by OBA in a dose-dependent and temporal manner, but neurotransmitter release partially recovered with the addition of CaM in membrane permeabilized PC12 cells. OBA and several synthetic CaM antagonists suppressed Ca²⁺-dependent glutamate release from cerebral cortical neurons, but not from cerebellar granule cells. Myosin Va, a CaM binding protein, localized to synaptic vesicles of PC12 cells and cerebral cortical neurons, but not in cerebellar granule cells. OBA suppressed Ca²⁺-induced myosin Va dissociation from secretory vesicles, and inhibited secretory vesicle motility in PC12 cells. These results suggest that CaM, although not essential, regulates neurotransmitter release in a subset of neurons and secretory cells, and myosin Va is a possible target of OBA in this process.
authors: School of Life Sciences, Tokyo University of Pharmacy and Life Science, Horinouchi, Hachioji, Tokyo 192-0392, Japan.
authors: Kosuke
authors: K
authors: Ando
authors: Yoshihisa
authors: Y
authors: Kudo
authors: Kyota
authors: K
authors: Aoyagi
authors: Ryoki
authors: R
authors: Ishikawa
authors: Michihiro
authors: M
authors: Igarashi
authors: Masami
authors: M
authors: Takahashi
mesh_terms: D000818:Animals; D002147:Calmodulin / Q000378:metabolism*; D002531:Cerebellum / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D002540:Cerebral Cortex / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D004305:Dose-Response Relationship, Drug; D018698:Glutamic Acid / Q000378:metabolism*; D018995:Myosin Heavy Chains / Q000378:metabolism; D024701:Myosin Type V / Q000378:metabolism; D009474:Neurons / Q000166:cytology / Q000187:drug effects / Q000378:metabolism*; D016716:PC12 Cells; D051381:Rats; D054830:Sesterterpenes / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D013572:Synaptic Vesicles / Q000187:drug effects / Q000378:metabolism
chemical_list: D002147:Calmodulin; C513081:Myo5a protein, rat; D054830:Sesterterpenes; D018698:Glutamic Acid; C040764:ophiobolin A; D024701:Myosin Type V; D018995:Myosin Heavy Chains
keywords: ACh; BSA; CREB; CaM; Cerebellar granule cells; Cerebral cortical neurons; DA; DMEM; DNase; Dulbecco’s modified Eagle’s medium; Dulbecco’s phosphate buffered saline; FCS; Glu; HRP; MEM; Myosin Va; Neurotransmitter release; OBA; PAGE; PBS; PC12 cells; SDS; SNAP-25; SNARE; VAMP-2; acetylcholine; bovine serum albumin; cAMP response element binding protein; calmodulin; deoxyribonuclease; dopamine; fetal calf serum; glutamate; hGH; horseradish peroxidase; human growth hormone; minimum essential medium; ophiobolin A; polyacrylamide gel electrophoresis; sodium dodecyl sulphate; soluble N-ethylmaleimide-sensitive fusion protein receptor; synaptosomal-associated protein of 25kDa; vesicle-associated membrane protein-2