Effect of neonatal benzpyrene imprinting on the brain serotonin content and nocistatin level in adult male rats.

Single neonatal treatment (imprinting) with 20 microg benzpyrene results in significant increase of the brain serotonin level in the striatum, while in the other four regions (cortex, brainstem, hippocampus, hypothalamus) when measured in adults can be detected. The nocistatin level of cerebrospinal fluid (CSF) significantly decreases, while there is no change in the plasma nocistatin level. The results call attention to the comprehensive imprinting effect of benzpyrene, which in addition to receptorial, hormonal and sexual behavioral disturbances causes lasting differences in the brain serotonin and nocistatin levels, probably influencing mood and pain tolerance.