Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy

Dendritic spines are protrusions emerging from the dendrite of a neuron and represent the primary postsynaptic targets of excitatory inputs in the brain. ...

University of Amsterdam

Gangliogliomas (GGs) and dysembryoplastic neuroepithelial tumors (DNTs) represent the most frequent type of neoplasms in pediatric medically intractable epilepsy. Several data suggest a pathogenetic relationship between GGs and other glioneuronal malformations of cortical development (MCDs), including activation of the Pi3K-mTOR signaling pathway. To further reveal these pathogenetic similarities, we investigated immunocytochemically the expression of phosphorylated (p)-PDK1, p-AKT, p-mTOR, p-4E-BP1, p-eIF4G, p-p70S6K and p-S6, the effector proteins ERM (ezrin/radixin/moesin) and the pathway regulator AMOG (adhesion molecule on glia) in both GGs and DNTs. Components of the Pi3K-mTOR signaling pathway were observed in a higher percentage of neuronal cells in GGs compared with control cortex. In DNTs, the expression of these components was low and comparable with the expression in control samples. Strong immunoreactivity for ERM was observed in GGs, but not in DNTs. Additionally, AMOG was strongly expressed within GGs (but not in DNTs) in CD34-positive precursor cells. These findings support the previously suggested pathogenic relationship between GG and MCDs concerning activation of the Pi3K-mTOR signaling pathway and suggest a different pathogenetic origin for DNTs. The strong expression of AMOG within the precursor cells of GG may represent an additional marker for the diagnostic evaluation of these glioneuronal lesions.

Pi3K-mTOR signaling and AMOG expression in epilepsy-associated glioneuronal tumors.

The intracellular messenger cGMP has been suggested to play a role in taste signal transduction in both vertebrates and invertebrates. In the present study, we have examined the role of the Drosophila atypical soluble guanylyl cyclases (sGCs), Gyc-89Da and Gyc-89Db, in larval and adult gustatory preference behaviors. We showed that in larvae, sucrose attraction requires Gyc-89Db and caffeine avoidance requires Gyc-89Da. In adult flies, sucrose attraction is unaffected by mutations in either gene whereas avoidance of low concentrations of caffeine is eliminated by loss of either gene. Similar defective behaviors were observed when cGMP increases were prevented by the expression of a cGMP-specific phosphodiesterase. We also showed that both genes were expressed in gustatory receptor neurons (GRNs) in larval and adult gustatory organs, primarily in a non-overlapping pattern, with the exception of a small group of cells in the adult labellum. In addition, in adults, several cells co-expressed the bitter taste receptor, Gr66a, with either Gyc-89Da or Gyc-89Db. We also showed that the electrophysiological responses of a GRN to caffeine were significantly reduced in flies mutant for the atypical sGCs, suggesting that at least part of the adult behavioral defects were due to a reduced ability to detect caffeine.

Drosophila gustatory preference behaviors require the atypical soluble guanylyl cyclases.

Le cGMP Messager intracellulaire a &eacute;t&eacute; sugg&eacute;r&eacute; de jouer un r&ocirc;le dans la transduction du signal de go&ucirc;t dans les vert&eacute;br&eacute;s et les invert&eacute;br&eacute;s. Dans la pr&eacute;sente &eacute;tude, nous avons examin&eacute; le r&ocirc;le des drosophile atypique guanylyl soluble cyclases (sGCs), Gyc-89Da et Gyc-89Db, dans les comportements des larves et des adultes de pr&eacute;f&eacute;rence gustative. Nous avons montr&eacute; que, chez les larves, attraction de saccharose exige Gyc-89Db et &eacute;viter la caf&eacute;ine n&eacute;cessite Gyc-89Da. Chez les mouches adultes, attraction de saccharose n&#39;est pas affect&eacute;e par des mutations dans deux g&egrave;nes alors que l&#39;&eacute;vitement de faibles concentrations de caf&eacute;ine est &eacute;limin&eacute; par la perte d&#39;un g&egrave;ne. Comportements d&eacute;fectueuses similaires ont &eacute;t&eacute; observ&eacute;s lorsque cGMP augmentations ont &eacute;t&eacute; emp&ecirc;ch&eacute;es par l&#39;expression d&#39;une phosphodiest&eacute;rase cGMP-sp&eacute;cifique. Nous avons &eacute;galement montr&eacute; que les deux g&egrave;nes sont exprim&eacute;s dans les neurones r&eacute;cepteurs gustatifs (GRNs) dans les organes gustatifs larvaires et adultes, principalement dans un mod&egrave;le sans chevauchement, &agrave; l&#39;exception d&#39;un petit groupe de cellules dans le Labelle adult. En outre, chez les adultes, plusieurs cellules de canal du r&eacute;cepteur de go&ucirc;t amer, Gr66a, avec Gyc-89Da ou Gyc-89Db. Nous avons &eacute;galement montr&eacute; que les r&eacute;ponses &eacute;lectrophysiologiques d&#39;une GRN &agrave; la caf&eacute;ine ont chut&eacute; en mutant de mouches pour la sGCs atypique, ce qui sugg&egrave;re qu&#39;au moins une partie de l&#39;adulte d&eacute;fauts comportements &eacute;taient due &agrave; une diminution de la capacit&eacute; &agrave; d&eacute;tecter la caf&eacute;ine.

Les comportements de pr&eacute;f&eacute;rence gustative de drosophile exigent les cyclases atypique guanylyl soluble.

Il Messaggero intracellulare di cGMP &egrave; stato suggerito di giocare un ruolo nella trasduzione del segnale di gusto sia vertebrati che invertebrati. Nel presente studio, abbiamo esaminato il ruolo della drosofila atipica solubile guanil cyclases (sGCs), Gyc-89Da e Gyc-89Db, in comportamenti di preferenza gustative larvale e adulto. Abbiamo mostrato che nelle larve, attrazione di saccarosio richiede Gyc-89Db ed evitare la caffeina Gyc-89Da. In mosche adulte, attrazione di saccarosio &egrave; influenzato da mutazioni nel gene sia considerando che scanso di basse concentrazioni di caffeina &egrave; eliminato dalla perdita di ogni gene. Simili comportamenti difettosi sono stati osservati quando aumenti di cGMP sono stati evitati mediante l&#39;espressione di una fosfodiesterasi cGMP-specifico. Abbiamo anche dimostrato che entrambi i geni erano espressi nei neuroni recettori gustativi (GRNs) in organi gustativi larvale e adulti, principalmente in un modello non sovrapposte, ad eccezione di un piccolo gruppo di cellule nel labello adulto. Inoltre, negli adulti, diverse celle co-expressed il recettore del gusto amaro, Gr66a, con Gyc-89Da o Gyc-89Db. Abbiamo anche dimostrato che le risposte elettrofisiologiche di un GRN alla caffeina sono sensibilmente ridotti in mosche mutant per sGCs atipica, suggerendo che almeno una parte dell&#39;adulto erano difetti comportamentali a causa di una ridotta capacit&agrave; di rilevare la caffeina.

Comportamenti di preferenza gustative drosofila richiedono i cyclases atipica guanil solubile.

We present a new super-resolution technique, Re-scan Confocal Microscopy (RCM), based on standard confocal microscopy extended with an optical (re-scanning) unit that projects the image directly on a CCD-camera. This new microscope has improved lateral resolution and strongly improved sensitivity while maintaining the sectioning capability of a standard confocal microscope. This simple technology is typically useful for biological applications where the combination high-resolution and high-sensitivity is required.

Wendy Timmermans

Center for Neuroscience,
Swammerdam Institute for Life Sciences,
Center for Neuroscience, Swammerdam Institute for Life Sciences

University of Amsterdam

Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy

Wendy Timmermans

.css-o250i3{font-size:18px;font-family:Open Sans,sans-serif;line-height:21.6px;}Center for Neuroscience,Swammerdam Institute for Life Sciences,Center for Neuroscience, Swammerdam Institute for Life Sciences

University of Amsterdam

Imaging Dendritic Spines of Rat Primary Hippocampal Neurons using Structured Illumination Microscopy

Center for Neuroscience,
Swammerdam Institute for Life Sciences,
Center for Neuroscience, Swammerdam Institute for Life Sciences