Development of neural lobe-like neurovascular contact regions after intrahypothalamic transection of the hypothalamo-neurohypophysial tract.
Fifteen days after bilateral transection of the hypothalamo-neurohypophysial tract at the level of the lateral retrochiasmatic area, neurovascular contact regions had developed proximal to 66% of the lesions. Contact regions developed in every case when neural lobe explants were placed into the lesions, and near approximately half of the lesions into which small pieces of sciatic or optic nerve were transplanted. Neurovascular contact regions were characterized by microvascular networks surrounded by dense neurophysin-immunoreactive plexuses. At the fine structural level, the organization of such regions resembled that of the neural lobe, with the single exception that capillaries were not fenestrated. Numerous neurosecretory axons were present, and palisades of neurosecretory axon terminals abutted perivascular basal laminae. Lamellopodia from glial cells partially ensheathed regenerating neurosecretory axons and often lay between terminals and the perivascular basal lamina. Terminals with many microvesicles and few neurosecretory granulated vesicles provided morphological evidence of hormone release.
Dellmann
H D
HD
Department of Veterinary Anatomy, College of Veterinary Medicine, Iowa State University, Ames 50011.
Carithers
J
J
D000818:Animals; D001808:Blood Vessels / Q000254:growth & development; D003714:Denervation; D007030:Hypothalamo-Hypophyseal System / Q000502:physiology*; D007031:Hypothalamus / Q000098:blood supply / Q000502:physiology* / Q000648:ultrastructure; D008297:Male; D008854:Microscopy, Electron; D009416:Nerve Regeneration / Q000502:physiology*; D009417:Nerve Tissue / Q000637:transplantation; D010904:Pituitary Gland, Posterior; D051381:Rats; D011919:Rats, Inbred Strains