TY - JOUR AU - Kardos, Julianna AU - Kovács, Ilona AU - Szárics, Éva AU - Kovács, Richárd AU - Skuban, N AU - Nyitrai, Gabriella AU - Dobolyi, Árpád AU - Juhász, Gábor Dénes TI - Uridine activates fast transmembrane Ca2+ ion fluxes in rat brain homogenates JF - NEUROREPORT J2 - NEUROREPORT VL - 10 PY - 1999 IS - 7 SP - 1577 EP - 1582 PG - 6 SN - 0959-4965 DO - 10.1097/00001756-199905140-00034 UR - https://m2.mtmt.hu/api/publication/112598 ID - 112598 N1 - [9/1999] LA - English DB - MTMT ER - TY - JOUR AU - Dobolyi, Árpád AU - Reichart, Anikó AU - Szikra, Tamás AU - Szilágyi, Nóra AU - Kékesi, Adrienna Katalin AU - Karancsi, Tamás AU - Slegel, P AU - Palkovits, Miklós AU - Juhász, Gábor Dénes TI - Analysis of purine and pyrimidine bases, nucleosides and deoxynucleosides in brain microsamples (microdialysates and micropunches) and cerebrospinal fluid JF - NEUROCHEMISTRY INTERNATIONAL J2 - NEUROCHEM INT VL - 32 PY - 1998 IS - 3 SP - 247 EP - 256 PG - 10 SN - 0197-0186 DO - 10.1016/S0197-0186(97)00090-9 UR - https://m2.mtmt.hu/api/publication/1065505 ID - 1065505 N1 - Department of Comparative Physiology, Eötvös Loránd Univ., Múzeum krt. 4/a, H-1088 Budapest, Hungary EGIS Pharmaceuticals Ltd., Keresztúri út 30-38, H-1106 Budapest, Hungary Laboratory of Neuromorphology, Semmelweis Univ. Medical School, Tüzltó u. 58, H-1094 Budapest, Hungary Cited By :47 Export Date: 2 February 2023 CODEN: NEUID Correspondence Address: Juhasz, G.; Department of Comparative Physiology, Muzeum Ktr 4a, H-1088 Budapest, Hungary AB - A new chromatographic method is reported for the synchronous analysis of endogenous purine and pyrimidine bases, ribonucleosides, and deoxyribonucleosides in brain samples. An optimized gradient chromatography system with a cooled reversed-phase column allows the detection of these compounds in very low concentrations in microsamples (microdialysates and micropunches). Chromatographic peaks were identified via the retention times of known standards, with detection at two wavelengths, and also by electrospray tandem mass spectrometry, which permits the identification of certain compounds at extremely low concentrations. The method was tested on in vivo brain microdialysis samples, micropunch tissue sample and cerebrospinal fluid of rats. Extracellular concentrations of pyrimidine metabolites in brain samples and of various purine metabolites in thalamic samples are reported here first. A comparison of the results on microdialysis and cerebrospinal fluid samples suggests that the analysis of cerebrospinal fluid provides limited information on the local extracellular concentrations of these compounds. Basic dialysis experiments revealed temporarily stable baseline levels one hour after implantation of the microdialysis probes. An elevated potassium concentration in the perfusion solution caused increases in the extracellular levels of adenosine and its metabolites, and of guanosine and the pyrimidine nucleoside uridine. LA - English DB - MTMT ER - TY - JOUR AU - Juhász, Gábor Dénes AU - Tarcali, J AU - Pungor, K AU - Pungor, Ernő TI - Electrochemical calibration of in vivo brain dialysis samplers JF - JOURNAL OF NEUROSCIENCE METHODS J2 - J NEUROSCI METH VL - 29 PY - 1989 IS - 2 SP - 131 EP - 137 PG - 7 SN - 0165-0270 DO - 10.1016/0165-0270(89)90024-1 UR - https://m2.mtmt.hu/api/publication/1227349 ID - 1227349 AB - Measurement of state-related changes in the concentration of an endogenous substance using the in vivo dialysis technique requires a definition of the factors which relate the concentration detected in the outflowing perfusate to the concentration actually occurring in the extracellular space in which the sampler is located. In determining these factors, a rapid and highly accurate detector system is required which measures the concentration recovery in the perfusate and the dead space of the entire sampling system. To reduce the limitations of the microdialysis technique, two electrochemical microcells were developed for calibration of dialysis probes by computerized voltammetry. The electrochemically calibrated samplers were implanted into freely moving cats to measure concentration changes of monoamine metabolites in synchrony with sleep stages identified by polygraphy in order to demonstrate the applicability of electrochemical calibration in dialysis methods used in behavioral investigations. LA - English DB - MTMT ER -