Activity of oxytocinergic neurons in the supraoptic nucleus under stimulation of α2-adrenoceptors in brattleboro rats

Jana Bundzikova, Zdeno Pirnik, Jens D. Mikkelsen, Dora Zelena, Alexander Kiss

Research output: Chapter in Book/Report/Conference proceedingConference contribution

4 Citations (Scopus)

Abstract

Vasopressin (AVP) deficient homozygous Brattleboro rats exhibit severe osmotic challenges due to waterless chronic hypernatremia and hyperosmolality. We investigated the effect of xylazine, an α2-adrenoceptor agonist, on the activity of oxytocinergic (OXY) neurons in the supraoptic nucleus (SON) of homozygous (di/di), heterozygous (di/+), and control (+/+) rats. Ninety minutes after saline (0.1 mL/100 g b.w., i.p.) or xylazine injection (10 mg/kg, i.p.) rats were anaesthetized with pentobarbital (50 mg/kg i.p.) and sacrificed by transcardial perfusion with fixative. Activity of OXY neurons was evidenced by nuclear Fos protein immunoreactivity. Fos/OXY colabelings were analyzed on 40-μm thick coronal sections using computerized light microscope. As expected, plasma osmolality and water intake revealed high heterogenity within the di/di group of rats. Fos expression in SON of di/di rats was correlated with osmolality of each rat. In saline-treated rats, maximum activation of Fos reached around 4% in +/+, 20% in di/+ rats, and as much as 60% in di/di rats. Xylazine activated in SON about 70% of OXY-ergic neurons in +/+, 60% in di/+ rats, and more than 80% in di/di rats. The present findings indicate that in spite of the high spontaneous activity of SON OXY-ergic neurons due to the AVP deficiency in di/di rats, many of the silent OXY-ergic neurons in the SON remained acceptable for α2-adrenoceptor stimulation.

Original languageEnglish
Title of host publicationStress, Neurotransmitters, and Hormones Neuroendocrine and Genetic Mechanisms
PublisherBlackwell Publishing Inc.
Pages154-160
Number of pages7
ISBN (Print)9781573316927
DOIs
Publication statusPublished - Dec 2008

Publication series

NameAnnals of the New York Academy of Sciences
Volume1148
ISSN (Print)0077-8923
ISSN (Electronic)1749-6632

Keywords

  • Brattleboro rats
  • Fos-immunohistochemistry
  • Oxytocin
  • Supraoptic nucleus
  • Xylazine

ASJC Scopus subject areas

  • Neuroscience(all)
  • Biochemistry, Genetics and Molecular Biology(all)
  • History and Philosophy of Science

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    Bundzikova, J., Pirnik, Z., Mikkelsen, J. D., Zelena, D., & Kiss, A. (2008). Activity of oxytocinergic neurons in the supraoptic nucleus under stimulation of α2-adrenoceptors in brattleboro rats. In Stress, Neurotransmitters, and Hormones Neuroendocrine and Genetic Mechanisms (pp. 154-160). (Annals of the New York Academy of Sciences; Vol. 1148). Blackwell Publishing Inc.. https://doi.org/10.1196/annals.1410.016