Nutritional parameters modify muricidal behavior of male Wistar rats: preventive effects of amino acids and 4' Cl...

In male Wistar rats fed a diet enriched in polyunsaturated fatty acids and starch (PUFA+S), the percentage of muricidal (Mu) rats increased to 82% within 60 days. Mu rats had higher serum triglyceride levels and lower cholesterol levels than non-Mu rats. Water intake decreased in all rats on the PUFA+S diet concurrently with the increase in the proportion of Mu rats; protracted water restriction in rats fed standard diet also increased the percentage of Mu rats. In the offspring of two Wistar females fed the PUFA+S diet, the proportion of young Mu rats was 67%. When the PUFA+S diet was replaced with standard diet, the induced Mu behavior was not reversed. PK11195 (6 mg/kg i.p.), clonazepam (0.2 mg/kg i.p.), and flumazenil (15 mg/kg i.p.) were ineffective in reversing the induced Mu behavior, whereas 4'-chlorodiazepam (5 mg/kg i.p.) or muscimol (0.5 mg/kg i.p.) caused reversals of 63% or 50%, respectively. A 5-hydroxytryptophan overload (60 mg/kg i.p.) also reversed Mu behavior by 71%. All reversal effects were temporary. Pretreatment with yeast for 7 days before the PUFA+S diet was given prevented induction for more than 90 days on the PUFA+S diet, while similar pretreatment 4'Cl-diazepam resulted in 71% prevention of induction. The results are analyzed in terms of the involvement of endozepin, vasopressin, and serotonin receptors, and of possible genetic parameters.