 Pregnant rats eating B"a"P were shown to negatively affect the brain function in the late life of their offspring.At a time when synapses are first formed and adjusted in strength by activity, B"a"P diminished NMDA receptor-dependent nerve cell activity measured as mRNA expression of the NMDA NR2B receptor subunit.B"a"P has an effect on the number of white blood cells, inhibiting some of them from differentiating into macrophages, the body's first line of defense to fight infections.