Objective To investigate the afferent pathways of "Guanyuan"(CV 4) under normal and pathological states and to observe the effect of electroacupuncture(EA) on them.Methods Twenty-four female SD rats were randomly divided into normal control(NC)

NC+EA

ovariectomy(OVX) and OVX+EA groups

with 6 cases in each.Four weeks after OVX

Pseudorabies Virus(PRV

10 μl liquid containing 108 plaque-forming units) was injected into CV4.Thirty minutes after PRV injection

EA(2 Hz

2-3 mA) was applied to CV4 for 30 minutes

once daily for 3 days.Six hours after the third EA treatment

all the rats were perfused transcardially with 4% paraformaldehyde under anesthesia

followed by sampling the brain and spinal cord and cutting into sections(35 μm).Immunohistochemical method(rabbit anti-rat beta-galactosidase) was used to display PRV immunoreactive(PRV-IR) positive neurons.Results 1) After injection of PRV

PRV-IR positive cells widely distributed in the spinal cord(cervical

thoracic and lumbar segments)

brain stem(nucleus of solitary tract

cuneate nucleus

gigantocellular reticular nucleus

nucleus of spinal tract of trigeminal nerve

nucleus raphe magnus

locus caeruleus

etc)

hypothalamus and cerebral cortex in each group.2) After OVX

apparently fewer PRV-IR positive cells were found in some nuclei as medial septum nucleus(MSN)

arcuate nucleus(ARC)

diagonal band nucleus(DBN)

paraventricular nucleus(PVN) which have close relation with endocrine activity(P<0.05);and rarely seen in ventromedial hypothalamus(VMH) and lateral preoptic area(LPO)(P<0.01).But in OVX+EA group

PRV-IR positive cells in above regions or nuclei increased significantly(P<0.05 or P<0.01).No obvious difference was found between NC and NC+EA groups in the number of PRV-IR positive cells(P>0.05).Conclusion Following OVX

PRV-IR positive cells in neuroendocrine-related nuclei of hypothalamus reduced significantly in number;EA of "Guanyuan"(CV 4) can promote the recovery of these neurons in above mentioned nuclei.