Changes of brain serotonin and muricide behavior following chronic administration of theophylline in rats

Temporal modification of amygdaloid serotonin (5HT) content and the resultant muricide behavior, compared to isolated and olfactory bulbectomized rats, were studied after chronic theophylline administration. Theophylline raised amygdaloid 5HT after Day 28 and amygdaloid 5-hydroxyindoleacetic acid (5HIAA), its deaminated metabolite, after Day 7. Theophylline applied for 29 days elevated 5HT and 5HIAA in the amygdala, the diencephalon and the brain stem, but not in the cortex. Effects of theophylline were reduced latency and maintained tendency to kill, even after overnight muricide test. The 5HT content of the amygdala decreased in bulbectomized rats. Discrepancy between brain 5HT changes and aggressive behavior were discussed.