pituitrin and Blindness

Vasopressin (AVP) is both a neuroendocrine hormone located in magnocellular neurosecretory neurons of the hypothalamus of mammals but also a neurotransmitter/neuromodulator in the parvocellular suprachiasmatic nucleus (SCN). The SCN is the endogenous clock of the brain and exhibits a prominent circadian AVP rhythm. We have in this study of the brown 129sv mouse and the visual blind cone-rod homeobox gene knock out mouse (Crx(-/-) ) with degeneration of the retinal rods and cones, but a preserved non-image forming optic system, studied the temporal Avp expression in both the neurosecretory magnocellular and parvocellular vasopressinergic systems in both genotypes. We here present a detailed mapping of all classical hypothalamopituitary and accessory magnocellular nuclei and neurons in the hypothalamus by use of immunohistochemistry and in situ hybridization in both genotypes. Semiquantitative in situ hybridization revealed a very high expression of Avp mRNA in all the magnocellular nuclei compared with a much lower level in the parvocellular suprachiasmatic nucleus. In a series of mice killed every 4 hours, the Avp mRNA expression in the SCN showed a significant daily rhythm with a zenith at late day time and nadir during the dark in both the Crx(-/-) and the wild type mouse. None of the magnocellular neurosecretory neurons exhibited a diurnal vasopressin expression. Light stimulation of both genotypes during the dark period did not change the Avp expression in the SCN. This shows that Avp expression in the mouse SCN is independent of Crx-regulated photoreceptor systems.

Topics: Animals; Blindness; Circadian Rhythm; Female; Homeodomain Proteins; Hypothalamus; Male; Mice; Mice, 129 Strain; Mice, Knockout; Neurons; Photic Stimulation; Suprachiasmatic Nucleus; Trans-Activators; Vasopressins

Blindness caused by ischemic optic neuropathy in the hospital setting occurs perioperatively and in critically ill patients, but its etiology remains ill defined. We describe four critically ill patients who developed blindness within 1 mo of one another. Three cases occurred outside of the operative arena. Potential risk factors for the development of ischemic optic neuropathy, such as use of vasopressors, venous congestion, and hypotension, are described.

Topics: Accidents, Traffic; Blindness; Diabetes Mellitus, Type 1; Diabetic Ketoacidosis; Diverticulitis; Female; Flail Chest; Hemothorax; Humans; Intensive Care Units; Lung Injury; Male; Middle Aged; Myasthenia Gravis; Myocardial Infarction; Optic Nerve Injuries; Optic Neuropathy, Ischemic; Pancreatitis; Pelvic Bones; Prone Position; Risk Factors; Sepsis; Spinal Fractures; Vasopressins

The blind mole rat, Spalax, is a subterranean rodent with atrophied, subcutaneous eyes. Whereas most of the visual system is highly degenerated, the retino-hypothalamic pathway in this species has remained intact. Although Spalax is considered to be visually blind, circadian locomotor rhythms are entrained by the light/dark cycle. In the present study we used anterograde tracing techniques to demonstrate retinal afferents to the suprachiasmatic nucleus (SCN) and immunohistochemistry to examine the distribution of neuropeptides that are known to be involved in the regulation or expression of circadian rhythmicity. Based on the localization of retinal afferents and neuropeptides, the SCN can be divided into two subdivisions. The ventral region, which receives retinal afferents, also contains vasoactive intestinal polypeptide (VIP)-containing neurons, and fibers that are immunopositive to neuropeptide Y (NPY) and serotonin (5-HT). The dorsal region contains vasopressinergic neurons, but this latter cell population is extremely sparse compared to that described in other rodents. The dorsal region is also characterized by numerous VIP-immunoreactive fibers. The presence of NPY and 5-HT fibers suggests that the SCN receives afferent projections from the intergeniculate leaflet and from the raphe nuclei, respectively. These neuroanatomical results, together with previous studies of behavior, visual tract tracing, and immediate early gene expression, confirm that an endogenous clock and the capacity for light entrainment of circadian rhythms are conserved in the blind mole rat.

Topics: Animals; Axonal Transport; Blindness; Cholera Toxin; Circadian Rhythm; Female; Horseradish Peroxidase; Israel; Male; Mole Rats; Motor Activity; Nerve Fibers; Neurons; Neuropeptide Y; Neuropeptides; Serotonin; Suprachiasmatic Nucleus; Vasoactive Intestinal Peptide; Vasopressins; Visual Pathways; Wheat Germ Agglutinin-Horseradish Peroxidase Conjugate

Topics: Adrenal Glands; Adrenal Insufficiency; Blindness; Bradycardia; Brain; Electrolytes; Female; Glucagon; Glucose; Glucose Tolerance Test; Growth Hormone; Humans; Hypoglycemia; Hypopituitarism; Infant; Infant, Newborn; Infant, Newborn, Diseases; Insulin; Intellectual Disability; Male; Pituitary Gland; Seizures; Vasopressins

Topics: Androgens; Blindness; Breast Neoplasms; Cortisone; Cyclophosphamide; Estrogens; Female; Humans; Hypophysectomy; Methods; Pituitary Irradiation; Thiotepa; Thyroxine; Vasopressins; Yttrium Isotopes

Topics: Adrenocorticotropic Hormone; Blindness; Breast Neoplasms; Central Nervous System Diseases; Diabetes Insipidus; Fistula; Follow-Up Studies; Gold Isotopes; Humans; Hypophysectomy; Meningitis; Pituitary Irradiation; Sella Turcica; Vasopressins