Neurophysiological Development of Fetal Neostriatal Neurons Transplanted into Adult Neostriatum

Abstract

Behavioral studies of rats with excitotoxic neostriatal lesions have demonstrated functional recovery of locomotor activity, motor symmetry, skilled motor tasks and performance in maze learning tasks after grafting of fetal neostriatal tissue (Dunnett et al, 1988; Deckel et al, 1983; Isacson et al, 1986). Histological analysis of the grafted neostriatal tissue suggests that these effects are mediated by the survival and growth of neurons which for the most part have been classified as the medium—sized spiny cell of the neostriatum (McAllister et al, 1985; Clarke et al, 1988, DiFiglia et al, 1988). It has been further proposed that the grafted neurons function via a reinstatement of the neurocircuitry normally found in the neostriatum (Dunnett et al, 1988; for review see Norman et al, 1988). A number of techniques have been used to show that nigral, cortical, thalamic and raphe afferents grow into the grafted neostriatal tissue (Clarke et al, 1988; Wictorin et al, 1989; Pritzel et al, 1986; Wilson et al, 1987). Conversely, grafted neostriatal tissue has been shown to reinstate gamma amino butyric acid (GABA) release in the globus pallidus and substantia nigra in lesioned animals (Sirinathsinghji et al, 1988).