Effects of serotonin_1A agonists on cardio-vascular neurons in the rostral ventrolateral medulla of the rat

Serotonin_1A (5-HT_1A ) agonists produce hypotension via a central sympatholytic action. The rostral ventrolateral medulla (RVLM) plays an important role in providing the sympathetic drive. The purpose of the present, study was to determine whether 5-HT_1A agonists act directly on cardiovascular neu...

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Bibliographic Details
Published in:Japanese Journal of Pharmacology 1993, Vol.61 (suppl.1), p.134-134
Main Authors: Kyoji Taguchi, Shuji Ozaki, Motoaki Amano, Takanobu Ishizuka, Takao Kubo
Format: Article
Language:Japanese
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Summary:Serotonin_1A (5-HT_1A ) agonists produce hypotension via a central sympatholytic action. The rostral ventrolateral medulla (RVLM) plays an important role in providing the sympathetic drive. The purpose of the present, study was to determine whether 5-HT_1A agonists act directly on cardiovascular neurons in the RVLM. Wistar rats were anesthetized with urethane, paralyzed and artificially ventilated. Neurons were recorded in the RVLM area and some units were identified as reticulospinal units with collision techniques. Ionotophoretically applied 5-HT increased or decreased the spontaneous firing rate of cardiovascular neurons in the RVLM. Iontophoretic buspirone and 8-OH-DPAT, 5-HT_1A agonists, consistently inhibited firing of RVLM cardiovascular neurons. The effect of 8-OH-DPAT was antagonized by iontophoretic spiperone, a 5-HT_1A antagonist. Intravenous 8-OH-DPAT also inhibited the firing of RVLM cardiovascular neurons. These results provide evidence that 5-HT_1A agonists act directly on cardiovascular neurons in the rat RVLM.
ISSN:0021-5198