Binge-eating disorder is a common psychiatric disorder affecting ~2% of adults. Binge-eating was initiated in freely-fed, lean, adult, female rats by giving unpredictable, intermittent access to ground, milk chocolate over four weeks. The rats avidly consumed chocolate during 2 hr binge sessions, with compensatory reductions of normal chow intake in these sessions and the days thereafter. Bodyweights of binge-eating rats were normal. The model's predictive validity was explored using nalmefene (0.1-1.0mg/kg), R-baclofen (1.0-10mg/kg) and SB-334867 (3.0-30 mg/kg) (orexin-1 antagonist), which all selectively decreased chocolate bingeing without reducing chow intake. Sibutramine (0.3-5.0mg/kg) non-selectively reduced chocolate and chow consumption. Olanzapine (0.3-3.0mg/kg) was without effect and rolipram (1.0-10mg/kg) abolished all ingestive behaviour. The pro-drug, lisdexamfetamine (LDX; 0.1-1.5mg/kg), dose-dependently reduced chocolate bingeing by ⩽ 71% without significantly decreasing normal chow intake. Its metabolite, D-amphetamine (0.1-1.0mg/kg), dose-dependently and preferentially decreased chocolate bingeing ⩽ 56%. Using selective antagonists to characterize LDX's actions revealed the reduction of chocolate bingeing was partially blocked by prazosin (α1-adrenoceptor; 0.3 and 1.0mg/kg) and possibly by SCH-23390 (D1; 0.1mg/kg). RX821002 (α2-adrenoceptor; 0.1 and 0.3mg/kg) and raclopride (D2; 0.3 and 0.5mg/kg) were without effect. The results indicate that LDX, via its metabolite, d-amphetamine, reduces chocolate bingeing, partly by indirect activation of α1-adrenoceptors and perhaps D1 receptors.

The respiratory changes wvhich take place in slices of tubers and tuberous roots have long been of interest to plant physiologists. As early as 1887, the wound respiration of white potato tubers was described (3), and since then many of the factors affecting this phenomenon have been analyzed (17). In recent years, the fact that the developed respiration is resistant to cyanide andl carbon monoxide has attracte(d special attention (18,25 The potato tuber slices, in which there is a striking change within one day, seemii ideally suited for further investigations on the problem of inhibitorresistant respiration. The plan of the present study has been to compare the respiratory mechanisms in freshly-cut and day-old slices, and to ascertain the conditions necessary for the development of the wound respiration. The w\ork has been carried on at two levels: with tissue slices and with isolated cell fractions. Oxygen uptake h1as been used as a measure of respiratory activity, and its coupling to phosphorylation estimated by following phosphate uptake. The respiratory components involved in hydrogen and electron transport have been exanmined by both enzymatic and spectrophotometric techniques. The evidence indicates that during the aerobic incubation of potato slices there is a metabolism-dependent moidification of the mitochondrial respiratory chain, prob-1

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BIOCHEMISTRY: CLICK AND HACKETT 243 the cell, or the reading of the DNA molecules for RNA synthesis or replication is undisturbed by the breaks.The behavior of infectivity at alkali pH suggests that single-stranded rings are infectious; only further experiments may, however, decide whether this is true.Two results remain to be explained: (1) the difference in sedimentation velocity of the ring and of the linear molecules is larger than for other ring-shaped molecules, such as those of OPX DNA"2 or X DNA;16 (2) the ring is unstable, as suggested by the kinetics of DNAase digestion. It can be tentatively suggested that they are the consequence of the combination of double strandedness and of the size of the ring.We are grateful to Prof. R. L. Sinsheimer for useful discussions. The competent and dedicated assistance of Miss Maureen Muir is gratefully acknowledged.This work will be supplemented by studies with the analytical ultracentrifuge.'7