Behavioral and neurochemical changes in pups prenatally exposed to methamphetamine.

Behavioral and neurochemical changes were examined in pups after repeated prenatal treatment with methamphetamine (MAP). MAP-pretreated pups showed decreased total motor activity with increased vertical activity. The reactivity to sound stimuli in MAP-pups differed from that in controls, suggesting impaired reactivity to the surroundings. No difference was found in development of the circadian rhythm of motor activity between MAP- and control pups. No behavioral sensitization to MAP was found in MAP-pups, regardless of the repeated prenatal exposure to MAP. This finding suggests that there is a certain developmental stage of the brain that is critical for long-term sensitization to dopamine agonists due to chronic MAP administration. Coincident with this, no change was found in the striatal catecholamine concentrations in MAP-pups. Radioreceptor assaying of various neurotransmitter receptors showed a significant decrease in the Bmax of 3H-spiperone binding in the frontal cortex of MAP-pups. These findings suggest that prenatal treatment with MAP produces impaired reactivity to the surroundings, in which the hyperserotonergic state of the frontal cortex may play an important role.