caa a22 4500 465739075 CHVBK 20180323111803.0 cr unu---uuuuu 170327e19900301xx s 000 0 eng 10.1007/BF02244596 doi (NATIONALLICENCE)springer-10.1007/BF02244596 Intravenous cocaine self-administration in rats is reduced by dietary l -tryptophan [Elektronische Daten] [Marilyn Carroll, Sylvie Lac, Marisel Asencio, Rebecca Kragh] Rats were trained to self-administer intravenously-delivered cocaine. Four lever-press responses resulted in a cocaine infusion (0.2 mg/kg) during daily 24-h sessions. The rats were also trained to obtain water from tongue-operated solenoid-driven drinking spouts. Ground food and water from a standard drinking bottle were also available. When cocaine injections reached stable levels,l-tryptophan was mixed with the rats' food for 5 days. Three concentrations ofl-tryptophan (2, 4, and 8%) were tested in different groups of five rats each. Three other groups of five rats each received the samel-tryptophan treatments; however, in these rats saline was substituted for cocaine and a sweet drinking solution consisting of glucose and saccharin (G + S) replaced water in the automatic drinking device. Two other groups consisting of five rats each self-administered a higher (0.4 mg/kg) or lower (0.1 mg/kg) unit dose of cocaine and food adulterated with 4% tryptophan. At the two higher concentrationsl-tryptophan reduced cocaine infusions by at least 50% during the 5 days of treatment, and cocaine infusions returned to baseline levels within 48 h after the regular diet was restored. Responding reinforced by the G + S solution was not altered by any of thel-tryptophan concentrations. Food intake was substantially lowered by the 8%l-tryptophan concentration; however, water intake, responding on an inactive lever, and the number of saline infusions were not affected by addition ofl-tryptophan to the food.l-Tryptophan had the same magnitude of effect on self-administration of the 0.1 and 0.2 mg/kg unit doses of cocaine, but behavior maintained by the highest cocaine dose (0.4 mg/kg) was resistant to the effect ofl-tryptophan. The results of this experiment indicate thatl-tryptophan reduces behavior reinforced by IV cocaine infusions. Springer-Verlag, 1990 Intravenous nationallicence Cocaine nationallicence Self-administration nationallicence Dietary l -tryptophan nationallicence Serotonin (5-HT) nationallicence Carroll Marilyn Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut Lac Sylvie Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut Asencio Marisel Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut Kragh Rebecca Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut Psychopharmacology Springer-Verlag 100/3(1990-03-01), 293-300 0033-3158 100:3<293 1990 100 213 https://doi.org/10.1007/BF02244596 text/html Onlinezugriff via DOI 1 research-article jats NATIONALLICENCE 856 40 https://doi.org/10.1007/BF02244596 text/html Onlinezugriff via DOI NATIONALLICENCE 700 1- Carroll Marilyn Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut NATIONALLICENCE 700 1- Lac Sylvie Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut NATIONALLICENCE 700 1- Asencio Marisel Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut NATIONALLICENCE 700 1- Kragh Rebecca Psychiatry Department, University of Minnesota Medical School, Box 392 UMHC, 55455, Minneapolis, MN, USA aut NATIONALLICENCE 773 0- Psychopharmacology Springer-Verlag 100/3(1990-03-01), 293-300 0033-3158 100:3<293 1990 100 213 Metadata rights reserved Springer special CC-BY-NC licence nationallicence BK010053 XK010053 XK010000 NATIONALLICENCE NATIONALLICENCE NL-springer