title: Morphological substrate of the catecholaminergic input of the vasopressin neuronal system in humans.
abstract: It has been postulated that the stress response is associated with water balance via regulating vasopressin release. Nausea, surgical stress and insulin-induced hypoglycaemia were shown to stimulate vasopressin secretion in humans. Increased vasopressin release in turn induces water resorption through the kidneys. Although the mechanism of the stress-mediated vasopressin release is not entirely understood, it is generally accepted that catecholamines play a crucial role in influencing water balance by modulating the secretion of vasopressin. However, the morphological substrate of this modulation has not yet been established. The present study utilised double-label immunohistochemistry to reveal putative juxtapositions between tyrosine hydroxylase (TH)-immunoreactive (IR) catecholaminergic system and the vasopressin systems in the human hypothalamus. In the paraventricular and supraoptic nuclei, numerous vasopressin-IR neurones received TH-IR axon varicosities. Analysis of these juxtapositions with high magnification combined with oil immersion did not reveal any gaps between the contacted elements. In conclusion, the intimate associations between the TH-IR and vasopressin-IR elements may be functional synapses and may represent the morphological basis of vasopressin release modulated by stressors. Because certain vasopressin-IR perikarya receive no detectable TH innervations, it is possible that additional mechanisms may participate in the stress-influenced vasopressin release.
authors.affiliation: Neuroendocrine Organization Laboratory, Lake Erie College of Osteopathic Medicine, Erie, PA 16509, USA. bdudas@lecom.edu
authors.forename: B
authors.initials: B
authors.lastname: Dudás
authors.forename: K R
authors.initials: KR
authors.lastname: Semeniken
authors.forename: I
authors.initials: I
authors.lastname: Merchenthaler
mesh_terms: D000328:Adult; D000368:Aged; D001931:Brain Mapping; D002395:Catecholamines / Q000378:metabolism*; D005260:Female; D006801:Humans; D007031:Hypothalamus / Q000378:metabolism*; D021621:Imaging, Three-Dimensional; D007150:Immunohistochemistry; D066298:In Vitro Techniques; D008297:Male; D008875:Middle Aged; D009434:Neural Pathways / Q000378:metabolism; D013569:Synapses / Q000378:metabolism; D014446:Tyrosine 3-Monooxygenase / Q000378:metabolism*; D014667:Vasopressins / Q000378:metabolism*
chemical_list: D002395:Catecholamines; D014667:Vasopressins; D014446:Tyrosine 3-Monooxygenase