Abstracts

Dietary control of seizures in both humans and animal models has been shown by administration of high-fat (ketogenic) diets and by calorie restriction of either ketogenic (humans and rodents) or normal diets (rodents). Calorie restriction is usually achieved by daily feeding of carefully measured quantities of chosen diets. Recently, it has been found that intermittent ad libitum feeding alters growth and fat deposition compared to that seen when animals are fed ad libitum continuously. We wished to determine whether intermittent feeding altered either seizure threshold (infusion of pentylenetetrazole [PTZ]) or severity (by maximal electroshock [MES]) and its effect upon glycemia and ketonemia. Ninety Sprague-Dawley male rats were fed either of three diets: (1) normal rodent chow, (2) a ketogenic diet, or (3) a high-carbohydrate diet. Each diet was fed to separate groups of rats on either of two schedules: (1) continuous, daily ad libitum feeding or (2) ad libitum feeding for 24 hours followed by complete removal of food for 24 hours. Animals fed on the intermittent schedule were tested for blood chemistries (glucose, [beta]-hydroxybutyrate [BHB]) both on days when they were fed and days when they were not fed. In general, rats fed the ketogenic diet continuously ad libitum showed higher seizure thresholds, higher levels of BHB, lower levels of glucose and more severe seizures than those fed the other two diets. Interestingly, rats fed intermittently showed higher BHB levels (for the KD only), lower glucose levels, equal or higher seizure threshold and equal or higher seizure severity than those fed respective diets ad libitum. We suggest that such observations may reflect animal adaptation to irregular feeding in the wild and the emergence of homeostatic mechanisms consistent with good health, including seizure resistance. (Supported by Department of Biology, Georgetown University.)