@article{MaiellaroLohseKitteetal.2016, author = {Maiellaro, Isabella and Lohse, Martin J. and Kitte, Robert J. and Calebiro, Davide}, title = {cAMP Signals in Drosophila Motor Neurons Are Confined to Single Synaptic Boutons}, series = {Cell Reports}, volume = {17}, journal = {Cell Reports}, number = {5}, doi = {10.1016/j.celrep.2016.09.090}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-162324}, pages = {1238-1246}, year = {2016}, abstract = {The second messenger cyclic AMP (cAMP) plays an important role in synaptic plasticity. Although there is evidence for local control of synaptic transmission and plasticity, it is less clear whether a similar spatial confinement of cAMP signaling exists. Here, we suggest a possible biophysical basis for the site-specific regulation of synaptic plasticity by cAMP, a highly diffusible small molecule that transforms the physiology of synapses in a local and specific manner. By exploiting the octopaminergic system of Drosophila, which mediates structural synaptic plasticity via a cAMP-dependent pathway, we demonstrate the existence of local cAMP signaling compartments of micrometer dimensions within single motor neurons. In addition, we provide evidence that heterogeneous octopamine receptor localization, coupled with local differences in phosphodiesterase activity, underlies the observed differences in cAMP signaling in the axon, cell body, and boutons.}, language = {en} } @article{BusseStrotmannStreckeretal.2014, author = {Busse, Kathy and Strotmann, Rainer and Strecker, Karl and Wegner, Florian and Devanathan, Vasudharani and Gohla, Antje and Sch{\"o}neberg, Torsten and Schwarz, Johannes}, title = {Adaptive Gene Regulation in the Striatum of RGS9-Deficient Mice}, series = {PLOS ONE}, volume = {9}, journal = {PLOS ONE}, number = {3}, doi = {10.1371/journal.pone.0092605}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-117048}, pages = {e92605}, year = {2014}, abstract = {Background: RGS9-deficient mice show drug-induced dyskinesia but normal locomotor activity under unchallenged conditions. Results: Genes related to Ca2+ signaling and their functions were regulated in RGS9-deficient mice. Conclusion: Changes in Ca2+ signaling that compensate for RGS9 loss-of-function can explain the normal locomotor activity in RGS9-deficient mice under unchallenged conditions. Significance: Identified signaling components may represent novel targets in antidyskinetic therapy. The long splice variant of the regulator of G-protein signaling 9 (RGS9-2) is enriched in striatal medium spiny neurons and dampens dopamine D2 receptor signaling. Lack of RGS9-2 can promote while its overexpression prevents drug-induced dyskinesia. Other animal models of drug-induced dyskinesia rather pointed towards overactivity of dopamine receptor-mediated signaling. To evaluate changes in signaling pathways mRNA expression levels were determined and compared in wild-type and RGS9-deficient mice. Unexpectedly, expression levels of dopamine receptors were unchanged in RGS9-deficient mice, while several genes related to Ca2+ signaling and long-term depression were differentially expressed when compared to wild type animals. Detailed investigations at the protein level revealed hyperphosphorylation of DARPP32 at Thr34 and of ERK1/2 in striata of RGS9-deficient mice. Whole cell patch clamp recordings showed that spontaneous synaptic events are increased (frequency and size) in RGS9-deficient mice while long-term depression is reduced in acute brain slices. These changes are compatible with a Ca2+-induced potentiation of dopamine receptor signaling which may contribute to the drug-induced dyskinesia in RGS9-deficient mice.}, language = {en} }