Premium
Localization of 5‐HT1A/B receptors in the rat brainstem, their distribution in IML‐projecting cells and activation during acute hypoxia
Author(s) -
Kline David D.,
Dantzler Heather A.,
Friskey Sarah A.,
Hasser. Eileen M.
Publication year - 2008
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.22.1_supplement.1169.11
Subject(s) - rostral ventrolateral medulla , brainstem , receptor , medulla oblongata , medulla , solitary tract , nucleus , medicine , endocrinology , serotonin , nucleus ambiguus , biology , stimulation , chemistry , neuroscience , central nervous system
Serotonin (5‐HT) type‐1 receptors contribute to cardiorespiratory (CR) function. Yet, distribution of these receptors in CR nuclei, and specifically in cells projecting to sympathetic preganglionic neurons in the intermediolateral (IML) cell column, is lacking. Whether 5‐HT1 containing cells are activated during the chemoreflex is also not known. We hypothesized acute hypoxia (10% O2, 3 hr) would stimulate IML‐projecting cells containing 5‐HT1 receptors. Immunohistochemistry in rat brainstem slices retrogradely‐labeled with fluorogold (FG, 1%) in the IML (T2 level) was used to test this notion. Fos‐like reactivity was used as a marker of cell stimulation. Fos, FG, 5‐HT1A and 5‐HT1B distribution was examined. 5‐HT1A and 1B labeling was similarly distributed in the following nuclei: nucleus of the solitary tract (NTS), facial, lateral paragigantocellularis, hypoglossal, ambiguus, rostral and caudal ventral lateral medulla (RVLM, CVLM), and occasionally, the Botzinger and pre‐Botzinger. In the RVLM, ~26% of 5‐HT1A and 18% of 5‐HT1B co‐labeled with FG, and a greater percent of 5‐HT1B than 1A co‐labeled with PNMT. In the NTS, 5‐HT1A/B did not co‐label with FG. Hypoxia increased Fos in the NTS, RVLM and CVLM compared to room air. In the NTS, a small percentage of Fos cells contained 5‐HT1A and in RVLM, some co‐labeled with FG and 5‐HT1B. These data suggest 5‐HT1 receptors may play a role in the CR response to hypoxia.