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Central Methysergide Prevents Renal Sympathoinhibition and Bradycardia during Hypotensive HemorrhageCentral methysergide prevents renal sympathoinhibition and bradycardia during hypotensive hemorrhage. Mean arterial pressure (MAP), heart rate (HR), and renal sympathetic nerve activity (RSNA) were measured in conscious rats during either hemorrhage or cardiopulmonary receptor stimulation with phenylbiguanide (PBG) after intracerebroventricular injection of the 5-HT1/5-HT2-receptor antagonist, methysergide (40 microg). Progressive hemorrhage caused an initial rise (109 +/- 33%) followed by a fall in RSNA (-60 +/- 7%) and a fall in HR (-126 +/- 7 beats/min). Methysergide delayed the hypotension and prevented both the sympathoinhibitory and bradycardic responses to hemorrhage. Systemic 5-HT3-receptor blockade did not influence responses to hemorrhage. The PBG infusion caused transient depressor(-25 +/- 6 mmHg), bradycardic (-176 +/- 40 beats/min), and renal sympathostimulatory (182 +/-47% baseline) responses that were not affected by central methysergide (-20 +/- 6 mmHg, -162 +/- 18 beats/min, 227 +/- 46% baseline). These data indicate that a central serotonergic receptor-mediated component contributes to the sympathoinhibitory and bradycardic responses to hypotensive hemorrhage in conscious rats. Furthermore, the same central 5-HT-receptor populations involved in reflex responses to hypotensive hemorrhage probably do not mediate the sympathoinhibitory response to cardiopulmonary chemosensitive 5-HT3 receptors.
Document ID
19990014463
Document Type
Reprint (Version printed in journal)
Authors
Veelken, Roland (Erlangen-Nuernberg Univ. Erlangen, Germany)
Johnson, Kim (Iowa Univ. Iowa City, IA United States)
Scrogin, Karie E. (Iowa Univ. Iowa City, IA United States)
Date Acquired
August 19, 2013
Publication Date
January 1, 1998
Publication Information
Publication: American Journal of Physiology
ISSN: 0363-6135
Subject Category
Aerospace Medicine
Funding Number(s)
CONTRACT_GRANT: N00014-97-1-0145
CONTRACT_GRANT: NAG5-6171
CONTRACT_GRANT: NIH-HL-07121
CONTRACT_GRANT: NIH-HL-57472
CONTRACT_GRANT: NIH-HL-09545
CONTRACT_GRANT: NIH-HL-14388
CONTRACT_GRANT: NAGw-4358
Distribution Limits
Public
Copyright
Other