caa a22 4500 477120571 CHVBK 20180405111635.0 cr unu---uuuuu 170330e19960301xx s 000 0 eng 10.1007/BF00408655 doi (NATIONALLICENCE)springer-10.1007/BF00408655 Interstitial noradrenaline concentration of rat hearts as influenced by cellular catecholamine uptake mechanisms [Elektronische Daten] [O. Obst, M. Linssen, G. Vusse, H. Kammermeier] Marked concentration differences of noradrenaline (NA) between the vascular and the interstitial compartment were detected by sampling interstitial transudate from isolated perfused rat hearts. The ratios of vascular/interstitial concentration amounted to 7.4 to 1.3 depending on the concentration of NA administered (3 × 10−9 to 10−6 M). These concentration differences were abolished by inhibitors of uptake1 desipramine (DMI) I and uptake, (O-methyl-isoprenaline (OMI)). Neuronal uptake, was characterized by a Km of 0.22 μmol/l and a Vmax of 370 pmol × min−1 × gWWT−1, extraneuronal uptake2 by a KUPTAKE of = 0.313 min−4. The apparent permeability surface area (P×S)-product calculated from uptake rate and transcapillary concentration difference was significantly decreased by administrating 100 μmol/l (NA) in presence of DMI. A presumed endothelial uptake mechanism contributing to catecholamine translocation was investigated in endothelial cells in culture. These cells showed a specific noradrenaline uptake with a Km of 4.35 μmol/l and a Vmax of about 75 pmol × min−1 x gWWT−1. Any inhibiton by inhibitors of both of the two noradrenaline uptakes was lacking. The uptake rate of this mechanism is insufficient to contribute to the diffusive conductivity of the capillary wall (P × S-product). We conclude from our investigations on interstitial concentrations of catecholamines and transcapillary concentration differences, that the capillary wall, owing to its metabolic and diffusional characteristics, influences the exchange of catecholamines to a substantial and physiologically relevant extent. Kluwer Academic Publishers, 1996 noradrenaline nationallicence interstitial fluid nationallicence permeability × surface area-product nationallicence extraneuronal uptake nationallicence rat coronary endothelium nationallicence Obst O. Department Physiology, Medical Faculty Aachen, Pauwelsstr 30, D-52057, Aachen, Germany aut Linssen M. Department Physiology, Medical Faculty Maastricht, Postbus 616, NL-Maastricht, The Netherlands aut Vusse G. Department Physiology, Medical Faculty Maastricht, Postbus 616, NL-Maastricht, The Netherlands aut Kammermeier H. Department Physiology, Medical Faculty Aachen, Pauwelsstr 30, D-52057, Aachen, Germany aut Molecular and Cellular Biochemistry Kluwer Academic Publishers; http://www.wkap.nl 163-164/1(1996-03-01), 173-180 0300-8177 163-164:1<173 1996 163-164 11010 https://doi.org/10.1007/BF00408655 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF00408655 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Obst O. Department Physiology, Medical Faculty Aachen, Pauwelsstr 30, D-52057, Aachen, Germany aut NATIONALLICENCE 700 1- Linssen M. Department Physiology, Medical Faculty Maastricht, Postbus 616, NL-Maastricht, The Netherlands aut NATIONALLICENCE 700 1- Vusse G. Department Physiology, Medical Faculty Maastricht, Postbus 616, NL-Maastricht, The Netherlands aut NATIONALLICENCE 700 1- Kammermeier H. Department Physiology, Medical Faculty Aachen, Pauwelsstr 30, D-52057, Aachen, Germany aut NATIONALLICENCE 773 0- Molecular and Cellular Biochemistry Kluwer Academic Publishers; http://www.wkap.nl 163-164/1(1996-03-01), 173-180 0300-8177 163-164:1<173 1996 163-164 11010 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer