Download Electro acupuncture activates glutamatergic neurons in

Electro Acupuncture Activates Glutamatergic Neurons in Arcuate Nucleus (ARC), which
Project into Ventral Lateral Periaqueductal Gray (vlPAG)
Yu Liu
Mentor: John C. Longhurst
Our previous studies have shown that electroacupuncture (EA) stimulation at the
Neiguan-Jianshi acupoints activates arcuate nucleus (ARC) to ventral lateral
periaqueductal gray (vlPAG) projection, which is essential for the inhibition of the
cardiovascular reflex. However, the neuronal projection between ARC and vlPAG that
can participate in the inhibition of the reflex during EA stimulation has not been
identified. The ARC is located in the mediobasal hypothalamus, adjacent to the third
ventricle. It is involved in the regulation of the autonomic nervous system and is
responsible for the regulation of blood pressure and heart rate. VlPAG is located around
the cerebral aqueduct within the midbrain. To show the anatomical relationship between
ARC and vlPAG, retrograde dye was injected into rats’ vlPAG. The retrograde dye was
absorbed by the axons in vlPAG, and then traveled to the cell body of the neuron.
Detecting cell labeling in the ARC shows the neuron projection between ARC and
vlPAG. The rats were then separated into two groups, an EA treated group and a shamoperated control group. Immunohistochemical study was performed on ARC sessions of
rats’ brains. The brain tissues were stained with c-fos antibody, an early gene expressed
by the activation of the cell. The expression of c-fos shows the activation of neurons by
electro acupuncture (EA) stimulus. As a result, tracers were found in ARC, which also
co-localize with c-fos. The expression of c-fos co-localized with tracer showed
dramatically greater increase in the EA treated rats than the control rats. This study shows
that electro acupuncture can activate neurons in ARC, which project their axons into
vlPAG.