Fetal hypothalamic transplants: neuronal and neurovascular interrelationships.

This investigation is one of a series aimed at developing an understanding of the neuroanatomical correlates of neuronal and vascular interactions that occur between heterografts of normal fetal hypothalamic tissue transplanted into the third cerebral ventricle of adult Brattleboro rats with homozygous autosomal diabetes insipidus (DI). Rapid vascular invasion of fetal neurografts occurred within 3 days and arose from the mantle plexus of portal capillaries in the underlying host median eminence. Host vessels also invaded from the periventricular stratum and preoptic area. In the ventral regions of heterografts neurites were observed to terminate upon perivascular spaces that surrounded local capillaries. Despite the development of apparently normal neurovascular zones, none of the DI host recipients demonstrated an amelioration of polydipsia or polyuria characteristic of diabeties insipidus.