Stress-induced norepinephrinerelease in the paraventricularnucleus of rats with brainstemhemisections: A microdialysis study

Karel Pacák, M. Palkóvits, Richard Kvetňanský, Irwin J. Kopin, David S. Goldstein

Research output: Contribution to journalArticle

66 Citations (Scopus)

Abstract

Immobilization (IMMO) of conscious rats evokes marked increases in release of norepinephrine (NE) in the paraventricular nucleus (PVN) of the hypothalamus, consistent with a role of NE in the PVN release of corticotropin-releasing hormone and therefore in pituitary-adrenocortical activation during stress. The present study examined the effects of surgical hemisection of the brainstem between the locus ceruleus and rostral portion of the medulla on release of NE in the PVN of the hypothalamus in vivo in conscious rats, at baseline and during IMMO. Concentrations of NE, the intraneuronal NE metabolite dihy-droxyphenylglycol (DHPG). and the dopamine metabolite dihydroxyphenylacetic acid (DOPAC) were measured in microdialysate samples obtained beginning 24 h after implantation of a microdialysis probe in the PVN either ipsilat-eral or contralateral to the hemisection. On the lesioned side, baseline levels of NE, DHPG, and DOPAC were significantly lower and IMMO-induced increases were smaller than in sham-operated rats. Contralateral to the hemisection, DOPAC levels were significantly reduced. Neither baseline levels nor IMMO-induced increases in plasma corticosterone levels differed between lesioned and sham-operated animals. The present results indicate that: (1) NE release in the PVN at baseline and during IMMO depends mainly on ascending medullary tracts from ipsilateral brainstem A1 and A2 catecholaminergic areas, with small contributions from the locus ceruleus and from contralateral medullary cells, and (2) brainstem hemisection does not influence IMMO-induced activation of the hypothalamic-pituitary-adrenocortical axis as indicated by plasma corticosterone levels in conscious rats.

Original languageEnglish
Pages (from-to)196-201
Number of pages6
JournalNeuroendocrinology
Volume58
Issue number2
DOIs
Publication statusPublished - 1993

Fingerprint

Microdialysis
Norepinephrine
Paraventricular Hypothalamic Nucleus
Immobilization
Brain Stem
Locus Coeruleus
Corticosterone
Hypothalamus
Acids
Corticotropin-Releasing Hormone
varespladib methyl
Dopamine

Keywords

  • Corticosterone
  • Dihydroxyphenylacetic acid
  • Dihydroxyphenylglycol
  • Immobilization stress

ASJC Scopus subject areas

  • Endocrinology
  • Endocrinology, Diabetes and Metabolism
  • Cellular and Molecular Neuroscience
  • Endocrine and Autonomic Systems
  • Neuroscience(all)

Cite this

Stress-induced norepinephrinerelease in the paraventricularnucleus of rats with brainstemhemisections : A microdialysis study. / Pacák, Karel; Palkóvits, M.; Kvetňanský, Richard; Kopin, Irwin J.; Goldstein, David S.

In: Neuroendocrinology, Vol. 58, No. 2, 1993, p. 196-201.

Research output: Contribution to journalArticle

Pacák, Karel ; Palkóvits, M. ; Kvetňanský, Richard ; Kopin, Irwin J. ; Goldstein, David S. / Stress-induced norepinephrinerelease in the paraventricularnucleus of rats with brainstemhemisections : A microdialysis study. In: Neuroendocrinology. 1993 ; Vol. 58, No. 2. pp. 196-201.
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