title: A critical importance of polyamine site in NMDA receptors for neurite outgrowth and fasciculation at early stages of P19 neuronal differentiation.
abstract: We have investigated the role of N-methyl-d-aspartate receptors (NMDARs) and gamma-aminobutyric acid receptors type A (GABA(A)Rs) at an early stage of P19 neuronal differentiation. The subunit expression was profiled in 24-hour intervals with RT-PCR and functionality of the receptors was verified via fluo-3 imaging of Ca(2+) dynamics in the immature P19 neurons showing that both NMDA and GABA excite neuronal bodies, but only polyamine-site sensitive NMDAR stimulation leads to enhanced Ca(2+) signaling in the growth cones. Inhibition of NR1/NR2B NMDARs by 1 muM ifenprodil severely impaired P19 neurite extension and fasciculation, and this negative effect was fully reversible by polyamine addition. In contrast, GABA(A)R antagonism by a high dose of 200 microM bicuculline had no observable effect on P19 neuronal differentiation and fasciculation. Except for the differential NMDAR and GABA(A)R profiles of Ca(2+) signaling within the immature P19 neurons, we have also shown that inhibition of NR1/NR2B NMDARs strongly decreased mRNA level of NCAM-180, which has been previously implicated as a regulator of neuronal growth cone protrusion and neurite extension. Our data thus suggest a critical role of NR1/NR2B NMDARs during the process of neuritogenesis and fasciculation of P19 neurons via differential control of local growth cone Ca(2+) surges and NCAM-180 signaling.
authors.affiliation: Laboratory of Molecular Pharmacology, Division of Pharmaceutical Sciences, Kanazawa University Graduate School of Natural Science and Technology, Kanazawa, Ishikawa 920-1192, Japan.
authors.forename: Danko
authors.initials: D
authors.lastname: Georgiev
authors.forename: Hideo
authors.initials: H
authors.lastname: Taniura
authors.forename: Yuki
authors.initials: Y
authors.lastname: Kambe
authors.forename: Takeshi
authors.initials: T
authors.lastname: Takarada
authors.forename: Yukio
authors.initials: Y
authors.lastname: Yoneda
mesh_terms: D000818:Animals; D002118:Calcium / Q000378:metabolism; D002454:Cell Differentiation / Q000187:drug effects; D002460:Cell Line; D016291:Dizocilpine Maleate / Q000494:pharmacology; D005786:Gene Expression Regulation / Q000187:drug effects; D020439:Growth Cones / Q000187:drug effects / Q000378:metabolism; D051379:Mice; D016501:Neurites / Q000187:drug effects / Q000502:physiology*; D018377:Neurotransmitter Agents / Q000819:agonists / Q000037:antagonists & inhibitors; D010880:Piperidines / Q000494:pharmacology; D011073:Polyamines / Q000378:metabolism*; D021122:Protein Subunits / Q000235:genetics / Q000378:metabolism; D011963:Receptors, GABA-A / Q000235:genetics / Q000378:metabolism; D016194:Receptors, N-Methyl-D-Aspartate / Q000235:genetics / Q000378:metabolism*
chemical_list: D018377:Neurotransmitter Agents; D010880:Piperidines; D011073:Polyamines; D021122:Protein Subunits; D011963:Receptors, GABA-A; D016194:Receptors, N-Methyl-D-Aspartate; D016291:Dizocilpine Maleate; C010739:ifenprodil; D002118:Calcium