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Anatomical Study of Serotonergic Nuclei Involvement in Cardiovascular Compensation following Hypotensive Hemorrhage
Author(s) -
Glasgow Jaimee,
Kung LingHsuan,
Vantrease Jaime,
Scrogin Karie
Publication year - 2009
Publication title -
the faseb journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.709
H-Index - 277
eISSN - 1530-6860
pISSN - 0892-6638
DOI - 10.1096/fasebj.23.1_supplement.785.1
Subject(s) - raphe nuclei , raphe , pentobarbital , serotonergic , nucleus raphe magnus , chemistry , serotonin , endocrinology , medicine , anesthesia , receptor
Lesion of serotonin (5‐HT) neurons in the hindbrain attenuates sympathetic compensation (SC) after hypotensive hemorrhage (HH) in awake rats. To determine the 5‐HT nuclei involved in SC, 5‐HT cells activated by HH were identified. Three days before the experiment, rats were implanted with vascular catheters under pentobarbital (65 mg/kg, i.p.) and randomized to 3 groups subjected to arterial blood withdrawal (21 ml/kg/10 min, n=7), hypotension (hydralazine, 10 mg/kg, i.v., n=8), or no treatment (n=7). After 90 min, rats were anesthetized (pentobarbital, 65 mg/kg, iv), perfused, and their brains processed for 5‐HT‐ and c‐Fos immunoreactivity. Larger numbers of double‐labeled cells were observed in the lateral extension of the B3 nucleus (P<0.05), the subependymal region lateral to B3 (P<0.05), and the raphe obscurus (P<0.01) in rats subjected to HH. In preliminary studies, adeno‐associated viral‐mediated knockdown of tryptophan hydroxylase 2 in the mid raphe obscurus attenuated SC (‐16% vs. +72% Δ baseline, 15 min after HH), while knockdown in more rostral regions did not. 5‐HT neurons in the brainstem, particularly in the raphe obscurus, likely contribute to SC following HH. Supported by HL 72354.