Effect of electroacupuncture on hypertensive and sympathetic excitability mechanism mediated by the paraventricular nucleus of the hypothalamus in spontaneous hypertensive rats.

Objective: To investigate the mechanism of electroacupuncture of sympathetic nerve activity and blood pressure reduction in the hypothalamic paraventricular nucleus (PVN) of spontaneous hypertensive rats (SHRs).

Methods: A total of 64 male SHRs were divided into four groups: model, sham-operated (Sham), electro-acupuncture (EA), and N-methyl-D-aspartate receptor antagonist and electroacupuncture (NRA + EA). In addition, 16 Wistar-Kyoto rats were used as controls. PVN stereotaxic surgery was performed in both the Sham and NRA + EA groups, while the EA and NRA + EA groups received 14 d of electroacupuncture. Blood pressure (BP) and heart rate (HR) were measured the day before the intervention and every other day. After 14 d of intervention, the rats in each group were tested for renal sympathetic nerve activity (RSNA). The associated factor levels were determined using Western blotting, reverse transcription-polymerase chain reaction (RT-PCR), enzyme-linked immunosorbent assay (ELISA) and immunofluorescence assays.

Results: In comparison to the model group, the EA and NRA + EA groups had significantly lower BP, HR, and RSNA (P < 0.01). The expression of N-methyl-D-aspartate receptor (NMDAR), angiotensin II (Ang II), angiotensin II type 1 (AT1), tumor necrosis factor-α, interleukin-1β, norepinephrine and arginine vasopressin was significantly lower in the EA and NRA + EA groups (P < 0.01). Moreover, the antihypertensive effect of NRA+EA group outperformed to the EA group.

Conclusions: Electroacupuncture effectively reduced the BP and sympathetic nerve excitability in SHRs. The mechanism was linked to the inhibition of NMDAR-mediated Ang II /AT1 and the inflammatory response in PVN.