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Relationship between dendrites of serotonin neurons and large midline vessels of the medulla.
Author(s) -
Dohle Carolin Isabel,
Wylie Christi J.,
Deneris Evan S,
Richerson George B
Publication year - 2006
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.20.4.a785-c
Subject(s) - raphe , serotonergic , serotonin , anatomy , brainstem , medulla , biology , medullary cavity , chemistry , neuroscience , receptor , biochemistry
Previous studies have demonstrated that medullary raphé neurons are closely related to midline blood vessels. Here, we characterized this relationship in further detail. First, using 10 μm fluorescent beads, we found that α‐smooth muscle actin is a reliable marker of arteries. Then, we transcardially perfused adult rats and obtained 20 um thick cryostat brainstem sections. With actin staining, we analyzed large blood vessels of at least 30 μm diameter in the raphe pallidus and ventral portion of the raphe obscurus and found that 86% of these vessels are arteries, while 14% are veins. Serotonergic neurons were found next to both arteries and veins. We perfused adult Pet1‐YFP positive mice transcardially, stained 20mμthick cryostat sections with an antibody against MAP2, a dendritic marker, and found that some serotonin neurons contact arteries with their dendrites. To determine the percentage of chemosensitive serotonergic raphé neurons, we exposed adult Pet1‐YFP mice to 10% CO 2 for 1 hour. We perfused the animals transcardially and stained for cFos, and found that a subset of serotonergic neurons near arteries expressed this marker. These results indicate that some chemosensitive serotonin neurons have dendrites near arteries. The subset that is near veins could sense venous CO 2 , or may play a role distinct from those near arteries.