Hypercortisolemia inhibits yohimbine-induced release of norepinephrine in the posterolateral hypothalamus of conscious rats

Karel Pacak, Ines Armando, Samuel Komoly, Koki Fukuhara, Virginia K. Weise, Courtney Holmes, Irwin J. Kopin, David S. Goldstein

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Abstract

Chronic hypercortisolemia attenuates yohimbine (YOH)-induced increments in plasma levels of the sympathetic neurotransmitter norepinephrine (NE). The present study used in vivo microdialysis to study the effects of hypercortisolemia on YOH-induced release of NE in the brain. Cortisol (25 mg/kg-day) or saline was infused sc into rats for 7 days via an osmotic minipump. Microdialysate and plasma concentrations of NE and its metabolites dihydroxyphenylglycol and meth- oxyhydroxyphenylglycol were measured before and after YOH (1 mg/kg, iv) administration in conscious animals, with microdialysate and plasma collections beginning 20-24 h after probe implantation. Chronic cortisol treatment resulted in attenuated NE, ihydroxyphenylglycol, and methoxyhydroxyphenylglycol responses in both microdialysate and plasma. The results indicate that YOH increases central neural as well as peripheral release, reuptake, turnover, and metabolism of NE and that hypercortisolemia suppresses these responses.

Original languageEnglish
Pages (from-to)1369-1376
Number of pages8
JournalEndocrinology
Volume131
Issue number3
DOIs
Publication statusPublished - Sep 1992

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ASJC Scopus subject areas

  • Endocrinology

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Pacak, K., Armando, I., Komoly, S., Fukuhara, K., Weise, V. K., Holmes, C., Kopin, I. J., & Goldstein, D. S. (1992). Hypercortisolemia inhibits yohimbine-induced release of norepinephrine in the posterolateral hypothalamus of conscious rats. Endocrinology, 131(3), 1369-1376. https://doi.org/10.1210/endo.131.3.1505468