Sound-induced seizures in rats fed an amino-acid deficient diet.

In the past 12 years well over a hundred papers have appeared which have dealt with "audiogenic" seizures. None has succeeded in delineating the basic mechanism or mechanisms involved in these response patterns. Nonetheless, there is accumulating a solid body of data which clearly indicates that changes within the internal environment of the animal subject influence the frequency and severity with which it can be made to convulse. Outstanding among these changes are those associated with generally reduced food intake as well as with deprivation of specific dietary constituents, particularly the B complex vitamins and magnesium (1). Meanwhile the basic metabolic systems are lipid, carbohydrate, and nitrogenous. Common sources of the nitrogenous dietary are cereal grains, such as corn and oats. These, however, do not possess as high a nutritional value as animal protein. For example, zein, the corn protein which constitutes the sole source of the nitrogenous dietary in our present experimental diet, is inadequate for growth or the maintenance of normal body weight, serum protein level, hemoglobin concentration, and red-cell count in rats (3, 6). These adverse physiological effects have provoked speculation concerning possible influences upon the several behavior processes in this species. Unpublished experiments of the first writer have indicated that rats maintained on a rolled oats diet showed wider shifts in activity level than their controls maintained on a standard laboratory diet; also, rats fed a zein diet showed a decrement in their performance of a simple maze habit. These latter also displayed greater irritability or nervousness as indicated by more biting and scratching at the retrace doors, explosive darting in the various alleys, greater distractibility, and resistance to handling. These last observations led to the conjecture that amino-acid deficient animals might also show increased susceptibility to sound-induced convulsions.