Neuropathology of "spinning syndrome" induced by prenatal intoxication with a PCB in mice

A striking motor dysfunction, "spinning syndrome," developed with a high frequency in weaning mice whose dams received oral 3,4,3',4'-tetrachlorobiphenyl (4-CB) during gestation (day 10 through day 16). The syndrome is permanent and is characterized by swift circling movements sustained in one direction at a minimal rate of 40 turns/min (usually 50 to 150 turns/min), restlessness, and hyperkinesia. Twenty-four spinners and 4-CB nonspinners and age-matched controls were subjected to histopathologic, histofluorescent, histochemical, and electron microscopic studies. The most reliable histopathologic marker for prenatal 4-CB injury to the CNS is the presence of cylindrical CNS peninsulas (CCPs) in the spinal and cranial nerve roots. The CCPs consist of either CNS-type myelinated fibers, unmyelinated fibers, or astroglial bundles in varying proportions, and are enclosed by a basement membrane. The CCPs are also observed in 4-CB nonspinners but in none of 12 controls studied. A selective defect in synaptogenesis induced prenatally by 4-CB is proposed as the primary event pursuant to the development of the CCPs, while interference with synaptogenesis may have occurred selectively in the striatonigral dopaminergic system. This is suggested by electron microscopy on the nucleus accumbens and also by the responses to administration of dopaminergic agonists and antagonist. The 4-CB induced clinico-pathologic anomaly may serve as a singular model for understanding human neurologic disorders, in particular, Werdnig-Hoffmann disease and minimal brain dysfunction syndrome.