Systemic signals contribute to induced morphological changes in the hypothalmo-neurohypophysial system.
A systemic injection of hypertonic saline causes morphological changes in the supraoptic nucleus (SON) of the hypothalamus and the posterior pituitary, including withdrawal of astrocytic glial processes from among magnocellular neuroendocrine cells (MNCs) in the SON and increases in neural apposition with the basal lamina (BL) in the posterior pituitary. This study investigated whether systemic adrenalin provides a signal for these changes. Three groups of rats were given intraperitoneal injections of hypertonic (1.5 M) or normal (0.15 M) NaCl and were sacrificed 5 h after injection. One group was given no additional treatment, one group was anesthetized from prior to injection through perfusion, and one group was bilaterally adrenal-medullectomized several days prior to injections. Morphometric analysis of electron micrographs revealed rats given 1.5 M NaCl with no additional treatment showed expected changes in the SON and pituitary. Rats given 1.5 M NaCl and anesthetized showed diminished responses in the SON, and no changes in the pituitary compared to anesthetized rats given 0.15 M NaCl. No changes in withdrawal of glial processes from among MNCs or in neural apposition with the BL were seen in medullectomized animals. Thus, both anesthesia and adrenal-medullectomy interfere with signals for glial retraction and suggest that these responses are mediated by adrenalin.
Beagley
G H
GH
Psychology Department, Alma College, MI 48801.
Hatton
G I
GI
D000313:Adrenal Medulla / Q000502:physiology; D000315:Adrenalectomy; D000758:Anesthesia; D000818:Animals; D001485:Basement Membrane / Q000648:ultrastructure; D004837:Epinephrine / Q000502:physiology; D007030:Hypothalamo-Hypophyseal System / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D008297:Male; D009457:Neuroglia / Q000648:ultrastructure; D010904:Pituitary Gland, Posterior / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure*; D051381:Rats; D017207:Rats, Sprague-Dawley; D015398:Signal Transduction / Q000187:drug effects; D012965:Sodium Chloride / Q000494:pharmacology; D013495:Supraoptic Nucleus / Q000187:drug effects / Q000502:physiology / Q000648:ultrastructure
D012965:Sodium Chloride; D004837:Epinephrine