Effects of Certain Antiepileptics on Behavioral and Electromyographic Seizure Patterns Induced by Maximal Electroshock in Mice

A model of binge-like eating behavior in mice that does not require food deprivation or stress

Binge eating disorder (BED) is characterized by excessive food intake during a short period of time and is often associated with obesity. Mouse models of binge-like eating behavior are lacking making it difficult to employ genetic models in the identification of mechanisms regulating excessive eating. We report a rapid and simple model to induce binge-like eating behavior in mice that does not require food deprivation or exogenous stressors. Weekly 24 h access to a nutritionally complete high energy diet (HED), along with continuous access to standard chow, resulted in a significant increase in HED intake following its presentation compared to mice that had continuous access to both diets. Mice exhibiting binge-like eating consumed one-third of their normal total daily caloric intake within 2.5 h of HED presentation. Moreover, total 24-h caloric intakes were increased by 50% in mice exhibiting binge-like eating. Following repeated cycles, binge-like eating of the HED was maintained over several weeks with no evidence of habituation or significant alterations in body weight and adiposity. Pharmacological evaluation of binge-like eating behavior was performed using clinically employed compounds. Interestingly, binge-like eating was dose-dependently decreased by fluoxetine, but not baclofen or topiramate. These data support clinical validation of this mouse model of binge-like eating behavior, as fluoxetine has been shown to reduce binge frequency in human subjects with BED. The availability of transgenic and knockout mice will allow for the determination of genes that are involved in the initiation and maintenance of binge-like eating behavior.

Antinociceptive effect of topiramate in models of acute pain and diabetic neuropathy in rodents

This study assesses the antinociceptive effect induced by different dosages of topiramate (TP), an anticonvulsant drug that is orally administered in models of neuropathic pain and acute pain in rats and mice, respectively. Orally administered TP (80 mg/Kg) in mice causes antinociception in the first and second phases of a formalin test, while in doses of 20 and 40 mg/Kg it was only effective in the second phase. TP (80 mg/Kg, p.o) also exhibited antinociceptive action in the hot plate test, however, it did not have an effect in the capsaicin test in mice, nor in the model of neuropathic pain in diabetic rats. The antinociceptive effect caused by TP (80 mg/Kg, p.o) in the formalin test was reversed by prior treatment with naloxone (opioid antagonist), but not with glibenclamide (antagonist of the potassium channel), ondansetron (antagonist of the serotonin 5HT3 receptor) or cyproheptadine (antagonist of the serotonin 5HT2A receptor).The data show that TP has an important antinociceptive effect in the models of nociception induced by chemical (formalin) or thermal (hot plate) stimuli, and that the opioid system plays a part in the antinociceptive effect, as shown by formalin.