Serotonin levels and turnover in different brain areas of isolated aggressive or non-aggressive strains of mice.

After eight weeks of individual housing DBA/2 but not C57 B1/6 (C57) mice showed high levels of aggressive responses in comparison with grouped mice. Social isolation did not modify serotonin (5-HT) levels in either strain of mice, while it produced a decrease of turnover rate in amygdala, lateral hypothalamus and pons in C57 mice and in lateral hypothalamus and pons of DBA mice. When isolated mice of both C57 and DBA strains are compared, no differences in turnover rate in amygdala and pons are evident, while isolated DBA mice show significant lower turnover values in lateral hypothalamus in comparison with isolated C57 mice. A possible suggestion emerging from our results is that aggressive responses exhibited by isolated DBA mice but not by isolated C57 mice may be related to lower 5-HT turnover rate in lateral hypothalamus.