Fast three-dimensional two-photon scanning methods for studying neuronal physiology on cellular and network level = Háromdimenziós, gyors, kétfoton-pásztázó eljárások sejt- és hálózatszintű idegsejtvizsgálatokhoz

Absztrakt. Az Orvosi Hetilap 2015. december 27-én megjelent 52. számának fenti közleményében [Orv. Hetil., 2015, 156(52), 2120–2126, DOI: 10.1556/650.2015.30329] Mezey Dávid nevét nem pontosan adták meg. A levelező szerző kérte a név helyesbítését. Abstract. Erratum to the article published on December 27th 2015 in Issue 52 of Orvosi Hetilap [Orv. Hetil., 2015, 156(52), 2120–2126, DOI: 10.1556/650.2015.30329]. The name of Dávid Mezey was not correctly typed. The corresponding author asked for the following correction to be published

Microglia protect against brain injury and their selective elimination dysregulates neuronal network activity after stroke

Microglia are the main immune cells of the brain and contribute to common brain diseases. However, it is unclear how microglia influence neuronal activity and survival in the injured brain in vivo. Here we develop a precisely controlled model of brain injury induced by cerebral ischaemia combined with fast in vivo two-photon calcium imaging and selective microglial manipulation. We show that selective elimination of microglia leads to a striking, 60% increase in infarct size, which is reversed by microglial repopulation. Microglia-mediated protection includes reduction of excitotoxic injury, since an absence of microglia leads to dysregulated neuronal calcium responses, calcium overload and increased neuronal death. Furthermore, the incidence of spreading depolarization (SD) is markedly reduced in the absence of microglia. Thus, microglia are involved in changes in neuronal network activity and SD after brain injury in vivo that could have important implications for common brain diseases

A pankreász vezeték sejtek bikarbonát szekréciójának kórélettana. = The pathophysiology of pancreatic ductal bicarbonate secretion.

A projekt fő célja a pankreász vezeték sejtek bikarbonát szekréciójának kórélettani vizsgálata volt. 1) Kísérleteinkben tisztázni tudtuk az epesavak pankreász duktuszt károsító hatásának okait: 1a) a nem konjugált epesavak a glükolitikus és oxidatív ATP szintézist jelentősen csökkentik ezáltal súlyos ATP depléciót alakítanak ki a pankreász duktális sejtjeiben. 1b) a nem-konjugált epesavak maxi-K+ csatornákat aktiválnak a pankreász duktális sejteken, mely új terápiás célpontot jelenthetnek akut biliáris pankreatitiszben. 2) Jelentős előrelépés történt a tripszin pankreász szekréciót gátló hatásának vizsgálatában is. Megtaláltuk azt a csatornát (CFTR Cl- csatorna) ami felelős a tripszin gátló hatásának kialakításáért. A kísérletekből megírt közlemény a Gastroenterology folyóiratban elbírálás alatt (under review) van. 3) Korábbi vizsgálataink arra utaltak, hogy a pankreatitisz súlyossága, a mitokondriális károsodás illetve a bikarbonát szekréció egymással szoros kapcsolatban van. A bázikus aminosavakkal kiváltott pankreatitisz során kimutattuk, hogy időrendi sorrendben a mitokondriális károsodás történik először, ami jelentősen befolyásolja a pankreatitisz súlyosságát. 4) Igazoltuk, hogy az iontranszporterek és a gyulladásos betegségek közötti összefüggések nem csak szerv specifikusak a pankreászra vonatkoztatva, hanem a teljes gasztrointesztinális traktusra (pl. vastagbél) is igazak lehetnek. | The main aim of the project was to investigate the role of bicarbonate secretion in pathophysiological conditions. 1) Our results helped us to understand the toxic effects of bile acids on pancreatic ductal epithelial cells. 1a) The non-conjugated bile acids cause mitochondrial damage followed by (ATP)i depletion. Bile acids inhibit the glycolytic metabolism of pancreatic ductal epithelial cells. 1b) We have shown for the first time that maxi-K+ channels have a crucial role in regulating HCO3 - secretion and are also essential for the bile acid-induced hypersecretion and, therefore, underlie the response of the pancreas to this noxious agent. 2) We showed for the first time that trypsin compromises pancreatic ductal bicarbonate secretion via a PAR-2 dependent inhibition of the apical anion exchanger and CFTR. This may contribute to the development of pancreatitis through promoting premature trypsinogen activation in the pancreatic ducts. Our manuscript is in revision at Gastroenterology. 3) We demonstrated that basic amino acids impair ATP synthase activity of isolated pancreatic, but not liver, mitochondria. Taken together, early mitochondrial injury caused by large doses of L-lysine may lead to the development of acute pancreatitis 4) We have also shown evidences that the relationship between the iontransporters and inflammatory disorders are not organ specific and it could be true in the whole GI tract

Sharp-Wave Ripple Doublets Induce Complex Dendritic Spikes in Parvalbumin Interneurons in vivo

Neuronal plasticity has been shown to be causally linked to coincidence detection through dendritic spikes (dSpikes). We demonstrate the existence of SPW-R-associated, branch-specific, local dSpikes and their computational role in basal dendrites of hippocampal PV+ interneurons in awake animals. To measure the entire dendritic arbor of long thin dendrites during SPW-Rs, we used fast 3D acousto-optical imaging through an eccentric deep-brain adapter and ipsilateral local field potential recording. The regenerative calcium spike started at variable, NMDA-AMPA-dependent, hot spots and propagated in both direction with a high amplitude beyond a critical distance threshold (~150 µm) involving voltage-gated calcium channels. A supralinear dendritic summation emerged during SPW-R doublets when two successive SPW-R events coincide within a short temporal window (~150 ms), e.g., during more complex association tasks, and generated large dSpikes with an about 2.5-3-fold amplitude increase which propagated down to the soma. Our results suggest that these doublet-associated dSpikes can work as a dendritic-level temporal and spatial coincidence detector during SPW-R-related network computation in awake mice

Fast 3D Imaging of Spine, Dendritic, and Neuronal Assemblies in Behaving Animals

SummaryUnderstanding neural computation requires methods such as 3D acousto-optical (AO) scanning that can simultaneously read out neural activity on both the somatic and dendritic scales. AO point scanning can increase measurement speed and signal-to-noise ratio (SNR) by several orders of magnitude, but high optical resolution requires long point-to-point switching time, which limits imaging capability. Here we present a novel technology, 3D DRIFT AO scanning, which can extend each scanning point to small 3D lines, surfaces, or volume elements for flexible and fast imaging of complex structures simultaneously in multiple locations. Our method was demonstrated by fast 3D recording of over 150 dendritic spines with 3D lines, over 100 somata with squares and cubes, or multiple spiny dendritic segments with surface and volume elements, including in behaving animals. Finally, a 4-fold improvement in total excitation efficiency resulted in about 500 × 500 × 650 μm scanning volume with genetically encoded calcium indicators (GECIs)