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 pres-sure 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 elec-troacupuncture reduces blood pressure; this reduction works through the stomach meridian. Microcirculation (2006) 13, 577–585. doi:10.1080/1073968060088521