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Hypothalamic pituitary adrenal axis and hypothalamic-neurohypophyseal responsiveness in water-deprived rats.
- Source :
-
Experimental neurology [Exp Neurol] 2001 Oct; Vol. 171 (2), pp. 329-41. - Publication Year :
- 2001
-
Abstract
- The differential effects of osmotic stimulation on magnocellular and parvocellular hypothalamic neurons were studied by analysis of corticotropin-releasing hormone (CRH) and vasopressin (VP) expression in controls and 48-h water-deprived rats subjected to either restraint for 1 h or a single lipopolysaccharide injection (250 microg/100 g). Water deprivation reduced basal CRH mRNA levels but the increments following 4 h of restraint or 6 h lipopolysaccharide (LPS) injection were similar to those in controls. In contrast, water deprivation had no effect on basal VP heteronuclear RNA (hnRNA) and mRNA levels in parvocellular neurons, but responses to restraint or LPS injection were reduced. VP expression in magnocellular paraventricular and supraoptic nuclei, and plasma sodium and vasopressin were higher in water-deprived rats, changes which were unaffected by restraint. LPS injection reduced VP mRNA but not hnRNA levels in magnocellular neurons and increased plasma vasopressin levels only in water-deprived rats independently of changes in plasma sodium. This was accompanied by an increase in vasopressin mRNA content in the posterior pituitary. The data show that the blunted ACTH responses to acute stress during chronic osmotic stimulation are correlated with the inability of parvocellular neurons to increase VP rather than CRH expression. In addition, LPS-induced endotoxemia causes disturbances of the magnocellular vasopressinergic system with an unexpected potentiation of osmotic simulated VP secretion. The lack of increase in VP transcription after LPS and changes in VP mRNA distribution suggest that endotoxemia affect the secretory process at the levels of the neurohypophyseal axon terminal.<br /> (Copyright 2001 Academic Press.)
- Subjects :
- Analysis of Variance
Animals
Escherichia coli
Lipopolysaccharides toxicity
Male
Paraventricular Hypothalamic Nucleus drug effects
Paraventricular Hypothalamic Nucleus physiology
Pituitary Gland, Posterior drug effects
Pituitary Gland, Posterior physiology
Pituitary-Adrenal System drug effects
Pro-Opiomelanocortin genetics
RNA, Messenger genetics
Rats
Rats, Sprague-Dawley
Restraint, Physical
Sodium blood
Stress, Psychological physiopathology
Transcription, Genetic
Vasopressins blood
Corticotropin-Releasing Hormone genetics
Gene Expression Regulation
Hypothalamo-Hypophyseal System physiology
Pituitary-Adrenal System physiology
Vasopressins genetics
Water Deprivation
Subjects
Details
- Language :
- English
- ISSN :
- 0014-4886
- Volume :
- 171
- Issue :
- 2
- Database :
- MEDLINE
- Journal :
- Experimental neurology
- Publication Type :
- Academic Journal
- Accession number :
- 11573986
- Full Text :
- https://doi.org/10.1006/exnr.2001.7784