Scopolamine-Induced Convulsions in Fasted Rats After Food Intake: The Effect of Duration of Food Deprivation

Abstract

Objective: Mice and rats fasted for 2 days and then treated with antimuscarinic drugs, scopolamine or atropine, develop convulsions soon after food intake. It has been demonstrated that deprivation of food for less than 48 h also causes convulsions in mice. Since there are differences in characteristics of the seizures between mice and rats, the present study evaluated whether rats also develop convulsions after being deprived of food for 3-24 h. Material and Method: Rats were deprived of food for 3, 6, 18, 24 and 52 h. At the time of testing, the animals were treated i.p. with saline or 3 mg/kg scopolamine and given food 20 min later. All animals were observed for 30 min, checking for the incidence and onset of convulsions. Results: The fasted animals treated with scopolamine developed convulsions after food intake. The incidence of convulsions was statistically significant in the 6, 18, 24 and 52 h deprived animals. However, neither the incidence nor the latency to seizures showed differences with respect to duration of food deprivation or fasting-induced weight loss. Conclusion: The present results demonstrate that the scopolamine treated rats that fasted for 24 h or less developed seizures after refeeding intake, indicating that food deprivation in itself, rather than its duration, seems to be the principal factor in the development of these convulsions.

Antimuscarinic-Induced Convulsions in Fasted Rats after Food Intake: EEG Patterns of Fasting, Scopolamine Treatment, and Convulsions

“…This study supported the findings that antimuscarinic treatment in 52 hours fasted rats causes convulsions after food intake. 2,5 While convulsions were never observed when fasted mice were administered saline and then allowed to eat, 2,4,6,7 rats in saline given control group developed stage 1, and 1 animal was observed showing stage 2 activity with tongue protrusion and neck spasm after food intake. The most important difference between these convulsions occurring in rats and mice was that convulsions were seen in the saline-treated rats, albeit with a low stage.…”

“…Also, rats seem less prone to develop convulsions with shorter periods of fasting in comparison with mice because 6 hours of fasting was required to reach the convulsive endpoint (stage 2+, 3, 4, or 5 activity). 5 Repeated pretreatment with scopolamine sensitizes rats to make vacuous jaw movements induced by pilocarpine. The density of muscarinic receptors of these animals has also been shown to increase in the lateral striatum.…”

“…[1][2][3] Deprivation for 6, 12, 18, and 24 hours causes these convulsions in antimuscarinic treated and refed mice and rats. 4,5 These findings suggest that the food deprivation itself causes convulsions but not the duration of the fasting period or weight loss. Hypoglycemia does not contribute to the occurrence of these convulsions because prevention of hypoglycemia development by water containing glucose intake during fasting has no preventive effect on the development of convulsions.…”