Modulation of neuronal activity in the nucleus raphé magnus by the 5-HT1-receptor agonist naratriptan in rat

Ellrich, Jens; Messlinger, Karl; Chiang, Chen Yu; Hu, James W

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Volume 90, Issue 3 , Pages 227-231, 15 February 2001

Modulation of neuronal activity in the nucleus raphé magnus by the 5-HT₁-receptor agonist naratriptan in rat

Jens Ellrich
- Institute of Physiology and Experimental Pathophysiology, Friedrich-Alexander-University, Universitätsstrasse 17, D-91054 Erlangen, Germany
- Department of Experimental and Clinical Pharmacology and Toxicology, Emil-Fischer-Center, Friedrich-Alexander-University, Fahrstrasse 17, D-91054 Erlangen, Germany
- Corresponding author. Tel.: +49-9131-85-22003; fax: +49-9131-85-22774
Karl Messlinger
- Institute of Physiology and Experimental Pathophysiology, Friedrich-Alexander-University, Universitätsstrasse 17, D-91054 Erlangen, Germany
Chen Yu Chiang
- Department of Oral Physiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G 1G6, Canada
James W Hu
- Department of Oral Physiology, Faculty of Dentistry, University of Toronto, Toronto, Ontario M5G 1G6, Canada

Received 18 October 1999; received in revised form 8 August 2000; accepted 9 August 2000.

Abstract

Modulatory effects of the new antimigraine drug naratriptan, a 5-HT₁-receptor-agonist, on neurons of the nucleus raphé magnus were examined in rat by extracellular recordings. In the nucleus raphé magnus neuronal activity decreased in on-cells and increased in off-cells after intravenous administration of naratriptan. The modulatory effects of naratriptan were similar to the well-known effects of morphine on neurons in the nucleus raphé magnus. The results of this study suggest central actions of naratriptan and may point to an involvement of the endogenous pain control system in the antinociceptive effects of the 5-HT₁-receptor-agonist.

Keywords: Antinociception, Brainstem, Descending inhibition, Headache