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Activated Projection from Arcuate Nucleus to Ventrolateral Periaqueductal Gray during Electroacupuncture: relation to neurons containing VGLUT3
Author(s) -
Guo Zhiling,
Liu Yu,
Longhurst John C.
Publication year - 2010
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.24.1_supplement.1019.2
Subject(s) - arc (geometry) , microinjection , electroacupuncture , chemistry , periaqueductal gray , stimulation , arcuate nucleus , neuroscience , medicine , hypothalamus , endocrinology , central nervous system , biology , acupuncture , pathology , midbrain , geometry , mathematics , alternative medicine
Our previous studies have shown that electroacupuncture (EA) at the Neiguan‐Jianshi acupoints (P5–P6, overlying the median nerve) attenuates sympathoexcitatory responses through activation of arcuate nucleus (ARC) and ventrolateral periaqueductal gray (vlPAG). Activation of the ARC leads to neuronal excitation of the vlPAG during EA. Neurons activated by EA contain vesicular glutamate transporter 3 (VGLUT3), a potential marker for glutamate. However, direct neuronal projections from the ARC to the vlPAG that could participate in central neural processing during EA have not been identified. Thus, the present study evaluated neuronal projections from the ARC to the vlPAG, especially with respect to neurons activated by EA. Seven to ten days after unilateral microinjection of a rodamine‐conjugated microsphere retrograde tracer (100 nl) into the vlPAG, rats were subjected to EA or served as a sham‐operated control. EA was performed for 30 min at P5–P6 acupoints bilaterally. Perikarya containing the microsphere tracer were found in the ARC of both groups. Compared to controls (needle placement without electrical stimulation, 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=6, P<0.01). Moreover, some neurons were triple‐labeled with c‐Fos, tracer and VGLUT3 in the ARC following EA stimulation (P<0.01). These results suggest that a direct neural pathway projecting from the ARC to the vlPAG may participate in EA‐modulation of sympathetic activity and that VGLUT3‐containing neurons are an important neuronal phenotype involved in this process (supported by NIH grants HL‐72125 and HL‐63313).