[Ultrastructural changes in the thalamus in chronic morphine intoxication and abstinence]

Electron microscopy was utilised to study the course of ultrastructure changes in Wistar rats' dorsomedial thalamus under the effect of chronic morphine intoxication (LD50 and increasing doses) and abstinence. Medial hypothalamic neurons proved highly vulnerable during dependence formation. Neurons, large dendrites and glia displayed various degrees of destruction increasing with the intoxication time. Synapses destruction paralleled the intoxication severity. In abstinence, the nerve tissue destructive processes were ousted by reparative ones. Small axon terminals emerged and large granular vesicles became hyperplastic under the adverse effect of morphinization and the morphine dependence formation.