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Attention deficit hyperactivity disorder (ADHD) is associated with increased risk of tobacco dependence. Nicotine, the main psychoactive component of tobacco, appears to be implicated in ADHD-related tobacco dependence. However, the behavioral responsiveness to nicotine of the prevalent animal model of ADHD, the spontaneously hypertensive rat (SHR), is currently underinvestigated. The present study examined the activational effects of acute and chronic nicotine on the behavior of adult male SHRs, relative to Wistar Kyoto (WKY) controls. Experiment 1 verified baseline strain differences in open-field locomotor activity. Experiment 2 tested for baseline strain differences in rotational behavior using a Rotorat apparatus. Adult SHR and WKY rats were then exposed to a 7-day regimen of 0.6 mg/kg/d s.c. nicotine, or saline, prior to each assessment. A separate group of SHRs underwent similar training, but was pre-treated with mecamylamine, a cholinergic antagonist. Nicotine sensitization, context conditioning, and mecamylamine effects were then tested. Baseline strain differences were observed in open-field performance and in the number of full rotations in the Rotorat apparatus, but not in the number of 90° rotations or direction changes. In these latter measures, SHRs displayed weaker nicotine-induced rotational suppression than WKYs. Both strains expressed nicotine-induced sensitization of rotational activity, but evidence for strain differences in sensitization was ambiguous; context conditioning was not observed. Mecamylamine reversed the effects of nicotine on SHR performance. These findings are consistent with the hypothesis that a reduced aversion to nicotine (expressed in rats as robust locomotion) may facilitate smoking among adults with ADHD.

In einer in Roux Archly ffir Entwicklungsmechanik erschienenen Arbeit 1 nimmt Aschoff Stellung zu meiner stammesgeschich~llehenTheorie der HerzmiBbildungen und kommt zu dem Ergebnis, dab fiir die Transpositionsformen vom Typus IIIb (Vertausehung yon Aorten-und Pulmonalisostium mit Eiupflanzung in dig nicht zugehSrigen Ventrikel bei intak~er Kammerseheidewand) diese Theorie nicht haltbar sei. Ieh habe auf die Aschoffsche Kritik bisher nieh~ geantwortet, tells weft ieh glaube, dab die Widerlegung derselben bereits aus meiner frfiheren Darstellung jener Theorie hervorgeht, tells weft Aschoffs Haupteinw~nde auf einer irrigen Vorstellung yon meiner Theorie bezfiglieh jener Transpositionsform beruhen, und ieh annahm, dab Aschoff selbst bei einer sps Gelegenheir sein Mil~verst~ndnis bemerken und berieh~igen wird. Nun ist aber aus dem Aschoffschen Institut eine zweite Arbeit, die yon Kung ~ erschienen, in welcher beide Autoren unveri~ndert an dem ffiiheren Irrtum festhalten, so dab ieh reich gezwungen sehe, dazu Stellung zu nehmen 3

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Inhaltsiibersicht.