@article{VonhofSirenFeuerstein1990, author = {Vonhof, S. and Sir{\´e}n, Anna-Leena and Feuerstein, Giora}, title = {Volume-dependent spatial distribution of microinjected thyrotropin-releasing hormone (TRH) into the medial preoptic nucleus of the rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-47421}, year = {1990}, abstract = {The present study was performed to qua ntify the distribution of a peptide neurotransmitter after microinjection into the medial preoptic area (POM), using a technique suitable for conscious animal preparations. The results indicate that only 50-ni volumes of injected tracer were sufficiently localized with 77 ± 9\% recovery in the POM. Injections of higher volumes resulted in an increasing spread of tracer into distant anatomical regions and structures, including the needle tract and cerebral ventricles. The amount of tracer localized in the POM decreased to 38±4\% (200 nl) (P < 0.05) and 41 ±8\% (500 nl) (P <0.05), respectively. The data suggest that the volume of injection is critical for intraparenchymal injections into structures of a diameter of I mm or less, such as the POM and should not exceed 50 nl in conscious animal preparations.}, subject = {Neurophysiologie}, language = {en} } @article{RettenmayrRodriguesdeMirandaRijntjesetal.1990, author = {Rettenmayr, N. M. and Rodrigues de Miranda, J. F. and Rijntjes, N. V. M. and Russel, F. G. M. and van Ginneken, C. A. M. and Strohmann, C. and Tacke, Reinhold and Lambrecht, G. and Mutschler, E.}, title = {Pharmacokinetic properties of the antimuscarinic drug [\(^3\)H]-hexahydro-sila-difenidol in the rat}, url = {http://nbn-resolving.de/urn:nbn:de:bvb:20-opus-64022}, year = {1990}, abstract = {The pharmacokinetics of tritiated hexahydrosila- difenidol ([\(^3\)H]-HHSiD) were examined in rats. Furthermore, the distribution of radioactivity was studied by means of whole body autoradiography. After i. v. administration of 2.9 mg/kg HHSiD plus [\(^3\)H]-HHSiD to anaesthetized rats bearing a catheter implanted in the ductus choledochus and receiving a mannitol infusion, HHSiD was rapidly distributed and metabolized. Only 5\% ofthe radioactivity was recovered in blood after 23 s and 0.4\% after 2.5 h. 64\% of the plasma radioactivity could be extracted with hexane from the samples taken 23 s after administration. 52\% of the radioactivity was eliminated within 2.5 h, 13\% by urinary and 39\% by biliary excretion. Following oral administration of 8.6 mg/kg HHSiD plus [\(^3\)H]-HHSiD there was an absorption of approximately one fourth of the administered radioactivity within 4 h. By means of whole body autoradiography (i. v. injection) as well as by tissue distribution measurement the highest Ievels of radioactivity were found in bile, urine, lung, kidney, adrenals, liver and .pancreas. Thus, after i. v. administration to rats HHSiD is rather quickly distributed, metabolized and excreted. This explains its low antimuscarinic potency in vivo.}, subject = {Anorganische Chemie}, language = {en} }