Search

Abstract: Gamma aminobutyric acid (GABA)-A receptor modulators constitute the majority of clinically relevant sedative-hypnotics. Zolpidem (Ambien) is a nonbenzodiazepine GABA-A receptor modulator that binds with high affinity to GABA-A receptors expressing alpha-1 subunits. The present study examined the effects of a new approach to the oral administration of zolpidem on locomotor activity, body weight, food intake, relative food intake, feed efficiency, anxiety, and visceral adiposity in rats. Effects of withdrawal associated with cessation of the drug were also recorded. A daily chronically administered oral 10mg/kg dose of zolpidem caused a decrease in locomotor activity, an increase in food intake and relative food intake, and a more positive feed efficiency during the drug-administration period. Anxiety and visceral adiposity also increased in animals receiving the drug. During withdrawal of zolpidem, there was a decrease in body weight, food intake, relative food intake, and anxiety, as well as a negative feed efficiency. These results suggest that zolpidem can modulate locomotor activity, metabolism, and anxiety-related behavior. A highly positive feed efficiency and increased visceral adiposity associated with zolpidem intake were unique findings of this study. [ABSTRACT FROM AUTHOR]

Melatonin levels, metabolic parameters, circadian rhythm activity patterns, and behavior were observed in rats subjected to a 12-h/12-h light/dark cycle (LD) compared to animals exposed to continuous dark (DD) or continuous light (LL). LD and DD animals were similar in melatonin levels, food intake, relative food intake, feed efficiency, water intake, circadian activity levels, and behavior. LL animals had lower melatonin levels in the subjective dark compared to LD and DD animals. Food intake, relative food intake, and water intake values were lower and feed efficiency was more positive in LL animals compared to LD and DD animals. In addition, LL animals exhibited greater visceral adiposity than the other two groups. The circadian rhythmicity of activity became free-running in LL animals and there was a decrease in overall activity. Notable behavioral changes in LL animals were an increase in irritability and excitability. Results indicate that a decrease in melatonin levels and concomitant changes in metabolism, circadian rhythms, and behavior are consequences of exposure to constant light. [ABSTRACT FROM AUTHOR]

Olanzapine is an atypical antipsychotic drug reported to increase appetite and alter body weight. These side effects, while fairly equal between men andwomen at the clinical level, arefar more common amongjemale than male rats. The objective of the present study was to investigate another mode of olanzapine administration in order to yield a preclinical outcome comparable to clinical results. Olanzapine was placed in sweetened condensed milk to ensure complete consumption of the daily dose of the drug at a specified time, which simulates a human taking the drug on a typical once-a-day schedule. Male and female rats were chronically administered olanzapine over a 3-week period. Olanzapine had no influence on male rats; however, it did produce an increase in food and water intake for female rats. Additionally, regardless of the drug, female rats were more active than male rats. While the current study simulated a human taking the drug on a typical once-a-day schedule, the results failed to replicate the proper diet and likely plasma levels in humans; and provided further support for the administration of olanzapine in food, similar to the human diet, or water throughout each day to emulate the olanzapineinduced weight gain in humans. [ABSTRACT FROM AUTHOR]