Postnatal maturation of prefrontal pyramidal neurones is sensitive to a single early dose of methamphetamine in gerbils (Meriones unguiculatus)

The effect of a single methamphetamine application on postnatal maturation of the prefrontal cortex was studied using pyramidal cell morphology and sp ine density as parameters of systemic plasticity. Male gerbils were injecte d a single dose of methamphetamine (METH, 50 mg/kg, i.p.) on postnatal day 14. On postnatal day 90, prefrontal cortices of METH-treated animals and sa line-treated controls were processed for Golgi-staining. Dendritic arbours of layer III and V pyramidal neurones were measured to describe pyramidal c ell morphology, and segmental spine counts were carried out. The results sh owed that a single postnatal METH-challenge significantly alters morphologi cal differentiation of pyramidal cells towards adulthood. Cells from METH-t reated animals showed a higher total dendritic length based on longer segme nts between subsequent dendritic branchings, with only the apical stem dend rite being shorter in METH-treated than in control subjects. The branching rate was slightly but not significantly increased in METH-treated animals. Nevertheless, spine density was significantly increased on all types of den drites, with apical dendrites of both layers III and V showing the highest drug-induced progression of about 50% compared to control values. The prese nt results are discussed with regard to probable clues they may provide for investigating neurobiological principles of psychotic behaviour in an anim al model.