3PT204 Localized neural activities in AIY interneuron of Caenorhab-ditis elegans : fluorescent imaging study(The 50th Annual Meeting of the Biophysical Society of Japan)
3PT204 線虫AIY介在神経細胞での局在した神経活動 : 蛍光イメージングによる研究(日本生物物理学会第50回年会(2012年度))

Hisashi Shidara, Junya Kobayashi, Ryo Tanamoto, Kohji Hotta, Kotaro Oka
2012 Seibutsu Butsuri  
TheBiophysical Society of Japan General IncorporatedAssociation animals isolated from U.K. were destroyed by cold stimuli, 2℃ for 48 hours. By contrast, most of wild-type animals can survive for 48 hours at 2℃ , afier cultivation at 15 degree. Detailed temperature-changes experiments revea]ed that the cold-resistance is established by temperature memory at adult stage, We measured cold-resistance in various mutant animals defective in sensoryneurons, Abnormal enhancement of cold-resistance is
more » ... und in the mutant animals defective in TAX-4 cGMP-gated channel, which is expressed in 10 pairs of sensoryneurons including thermo-sensoyneuron AFD and chemosensoryneurons. Developmental defect of AFD that is caused by mutatjon in OTX transcriptional factor did not affect cold-resistance, These results suggest that cold-resistance is controlled by sensory neurons excepting AFD, and that sensoryneurons transrnit inhibitory signaling for co]d resistance. To determine melecular pathway for co]d resistance, we referred previous DNA microarray ana]ysis {Sugi et al., Nature neurosci., 2011), So far, at least 1O genes such as endionuclease, tubu]in kinase and phosphatase PPI are invo]ved in cold-Teslstanee. 3PT202 Inhibitory effect of glutamate-stimulated astrocytes on action potentials evoked by bradykinin in cultured dersal root ganglion neurons Kazuo Suzuki, Keriji Tonaka, Minehisa Ono (Dept. Biomedical Engr, 7bkai Uhiv.)The patch-clamp and Ca2' -imaging techniques have reveaied that astrocytes have dynamic properties inc]uding ion channel activity, neurotransrnitter release, such as adenosine triphosphate (ATP) and glutamate. Our previous study dernonstrated that free nerve endings ofcultured neuron from dorsal root ganglion (DRG) are activated by bradykinin (BK). We study whether ATP and glutamate can modulate the BK-response of the neuron cultured with the astrocyte in the mouse DRG, and enunciate the role of the astrocyte in the nociceptive signal transmission using patch-clamp technique. The astroeytes wereidentifiedusingfluorescentantibody,anti-GFAP.Themembranepotential ofthe astrecyte was about -39 mV. The application ofglutamic acid (GA) to the bath evoked the opening of two kinds ofCl' channel of the astrocyte membrane with unjt conductance of about 380 pS and 35 pS in the cell-attached mode, respectively.ATPapplicationevokedtheepeningoftwokindsofK'channetof the astrocyte with unit conductance of about 60 pS and 29 pS, respectively. Application of BK te the neuron evoked an action potential (spike). The BKapplication ofconcomitantly with ATP increased the frequency Df BK-evoked spike ofthe neuron. Stimulation ofBK with GA inhibited the BK-evoked spike. The application of furosemide, a potent cotransporter (Na' -K' -Cl') inhibitor, prier to the stimulation ef BK with GA blocked the inhibition ofthe spike, It is thought that the inhibition of the spike is related to C]' movement from the astrocyte. 3pT2o3 ?vxewm{v*-F([asltas-mttg# (No} cosum Nitric oiide measurement in mice brain homogenate Yoshiichiro Kitamura, Akira Hirai, Toshihiko Nishio. Yutaka Kirino (Kttgawa Sbh. Pharm, Sbi., 7bkushima Bunri Uhiv.) It is known that nitric oxide CNO) plays important roles in a number of physiological processes over various animal spccies of vertebrate and invertebrate, such as neurotransmission, vasodilation and immune response. Especial]y in recent years, relationship between nitric oxide (NO) and aging has been received a lot of attention. However down-regulation of NO signaling during aging process is strongly suggested, NO dynamics in brain have net been studied in detail. Therefore, in this study, NO production in mice brain homogenate was rneasured using NO-specific electrode. Brain homogenates (cerebra] cortex, cerebellum and hippocampus) were pTepared from ma]e wi]dtype mice (8 and 120 weeks). After oxidation current of the NO electrode stabilized in the saline, each brain homogenate was added for estimation of basal NO production, To cenfi rm specificity ofthe electrode, brain homogenate was stimulated with calcium ion (Ca2'). Whell brain homogenate was added, NO concentration increased and was stabi]ized at constant tevel. Ca?' aceelerated the basal NO production in a concentration-dependent manner. However concentration of basal NO production did not so dlfferent in region and age, Ca]'-induced NO prodllction in aged rnice significantly decreased in every region compared with young mice. From these results, NO production from rnice brain hemDgenate was successfu11y measured w{th the NO-specific electrode. We also exarnined that aging induced down-regu]ation ofCa2'INO sigrialing in mice brain, 3PT204 The neural activities ofsubce]lular regions are important for understanding the relationship between the ce]lular morphology and the function in single neurons. From this view, ATY intenieuron of CZienorhabditis elegans has a very unique featurc ofCai' dynamics; Ca2' change is observed only on the specific region of neurites, but not on soma during odor and ternperature stimulation. To investigate this dynamics in subceltubar regions ofAIY in detail, we visualized the rnembrane potential and showed that its dynarnics is diffeTent frorn the Ca2' one.For visualization ofneural activities on specific neurons in C. elegans, we have developed a specific rnicro-fluidic device to fix the worm. The worm was applied to 1O'4 di]ution of isoamyl alcohol as the controlled odor stimulation during SO sec. The genetic Ca2' indicator (YC3.60) expressed in AIY has revealed the subcellular neural aetivities to the externaL environmental change. To compare membrane potential change with the dynamics, we also used voltage-sensitive fiuorescent protein (VSFP) 2,42 {Akemann et al., 20]O). VSFP2.42 revealed that the edor stirnulation depo]arized membrane potential both on the neurite and soma. In addition, the membrane potential showed oscillatien witb attenuation of the amplitude during odorant stimulation. These results suggest that AIY has the diversity of biophysical characteristics in the singie cell and it is necessary for understanding its function, 3PT205 Yoshimasa Kawato2'3 (tDept Univ of Tbkyo, Modulation ofhippocampal synaptic plasticity by corticosterone {CORT) has been attracting much attention, diue to its importance in stress responses, Many studies have investigated the chronic effbet of CORT, but rapid effect ofCORT in hippocampus is unc[ear, Here, we investigated effect of CORT, a major glucocorticoid in rat, on density and morphology of dendritic spine which is essentiat for memory storage processes, in adult male rat hippocarnpus. Tlie application of 1 pM CORT induced a rapid increase in the total density ofspines ofCAI pyramidal neurons within 1 h from O.98 spines/Fm te 1.24 spinesl"m, CORT increased the density of targe-head (O,5i .O pm) and middle-head spines (O.4-O.5 pm), but not small-head (O,2-O.4 pm) spines. Co-presence of RU486, an antagonist of glucocorticoid receptor (GR), cornpletely abolished the effbct of CORT. B]ocking ionotropic g]utamate receptors with MK-801 inhibited the CORT effect, This result suggests that Ca2+ homeostasis via NMDA receptors is necessary to CORT-induced spinegenesis. Blocking various kinases shows thatCORTenhancesspinogenesisviaMAPK,PKA,PKC,PI3Kandcalcineurin sigrialing pathways. In particular, the contribution of Erk MAPK and PKA is essential, Inhibition of protein synthesis reduced the CORT-induced spinogenesis but inhibltion of transcTiption. These results indicate that CORT drives the sigrialing pathway including synaptic GR and multiple kinase pathways in hippocampal CA1 neurons. (Komatsuzaki et al" 2012 PLoS-ONE) ]JVflXfDyta.
doi:10.2142/biophys.52.s175_3 fatcat:6dcp5q4wofa7tclz3abhaqesry