Acupuncture reduces experimental renovascular hypertension through mechanisms involving nitric oxide synthases.

OBJECTIVE To test the hypothesis that acupuncture on stomach 36 point (ST-36) reduces hypertension by activating nitric oxide synthase signaling mechanisms. METHODS The authors used the two-kidney, one-clip renal hypertension (2K1C) hamster model with electroacupuncture treatment. RESULTS Thirty-minute daily electroacupuncture treatment for 5 days reduced mean arterial pressure from 160.0 +/- 7.6 to 128.0 +/- 4.3 mmHg (mean +/- SEM), compared to 115.0 +/- 7.2 mmHg in sham-operated hamsters. Electroacupuncture increased periarteriolar NO concentration from 309.0 +/- 21.7 nM to 417.9 +/- 20.9 nM in the 2K1C hamster cheek pouch microcirculation when measured with NO-sensitive microelectrodes. Hypertension reduced endothelial nitric oxide synthase (eNOS) and neuronal nitric oxide synthase (nNOS) proteins relative to the sham-operated control, as measured by Western blotting. Electroacupuncture prevented the reduction of eNOS and nNOS associated with hypertension and showed even higher eNOS and nNOS expressions than sham-operated control in stomach and cheek pouch tissues, which are on the stomach meridian. Analysis of liver tissue, a non-stomach-meridian organ, indicated that electroacupuncture did not have a significant benefit in terms of enhanced expressions of eNOS and nNOS in the treated 2K1C hypertensive group. CONCLUSIONS Activation of eNOS and nNOS is one of the mechanisms through which ST-36 electroacupuncture reduces blood pressure; this reduction works through the stomach meridian.