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Activated Projection from Arcuate Nucleus to Rostral Ventrolateral Medulla by Electroacupuncture: relation to β‐endorphin
Author(s) -
Guo ZhiLing,
Liu Yu,
Moazammi Ali R.,
Longhurst John C.
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.1169.8
Subject(s) - rostral ventrolateral medulla , arc (geometry) , microinjection , chemistry , hypothalamus , nociceptin receptor , arcuate nucleus , medicine , medulla oblongata , electroacupuncture , endocrinology , nucleus , neuroscience , central nervous system , anatomy , receptor , opioid peptide , biology , opioid , acupuncture , pathology , geometry , mathematics , alternative medicine
Electroacupuncture (EA) at the Neiguan‐Jianshi acupoints (P5–P6, overlying the median nerve) attenuates sympathoexcitatory responses through μ opioid receptors in rostral ventrolateral medulla (rVLM). Arcuate nucleus (ARC) in the hypothalamus is a critical brain area in which perikaryia containing β‐endorphin are distributed. However, direct neuronal projection from ARC to rVLM that could participate in central neural processing during EA has not been identified. The present study evaluated neuronal projection from the ARC to the rVLM, especially respect with neurons activated by EA. After unilateral microinjection of a rodamine‐conjugated microsphere retrograde tracer into the rVLM, rats were subjected to sham control or EA at P5–P6 acupoints for 30 min. Perikarya containing the microsphere tracer were found in the ARC. Some of these neurons (27%) co‐localized with β‐endorphin. Compared to controls (n=5), c‐Fos immunoreactivity and neurons double‐labeled with c‐Fos, an immediate early gene, and the tracer were increased significantly in the ARC of EA‐treated rats (n=7, all P<0.05). Moreover, some neurons were triple‐labeled with c‐Fos, the tracer and β‐endorphin in the ARC following EA. These results suggest that a β‐endorphin‐containing neural pathway projecting from the ARC to the rVLM may participate in EA‐modulation of premotor sympathetic activity (supported by NIH, HL‐72125 and HL‐63313).