Electroacupuncture most effectively elicits depressor and bradycardic responses at 1 Hz in humans.

Author: Nakahara H1, Kawada T2, Ueda SY3, Kawai E3, Yamamoto H4, Sugimachi M2, Miyamoto T3.
Affiliation: 1Graduate School of Health Sciences, Morinomiya University of Medical Sciences, 1-26-16 Nankokita, Suminoe, Osaka, Osaka, 559-8611, Japan. nakahara@morinomiya-u.ac.jp. 2Department of Cardiovascular Dynamics, National Cerebral and Cardiovascular Center, 5-7-1 Fujishirodai, Suita, Osaka, 565-8565, Japan. 3Graduate School of Health Sciences, Morinomiya University of Medical Sciences, 1-26-16 Nankokita, Suminoe, Osaka, Osaka, 559-8611, Japan. 4Division of Cardiology, Department of Medicine, Faculty of Medicine, Kinki University, 377-2 Ohno-higashi, Sayama, Osaka, 589-8511, Japan.
Conference/Journal: Clin Auton Res.
Date published: 2015 Dec 22
Other: Word Count: 225


Abstract
PURPOSE:
Acupuncture stimulation is known to act on the autonomic nervous system and elicits depressor and bradycardic effects. However, previous studies on humans did not conduct quantitative analyses on optimal acupuncture conditions such as the stimulation frequency and duration to achieve maximum depressor and bradycardic effects. The aim of the present study was to investigate the effects of varying stimulation frequencies of electroacupuncture on time-dependent changes in blood pressure and heart rate in humans.
METHODS:
Twelve healthy volunteers participated in the study. An acupuncture needle was inserted at the Ximen acupoint (PC4 according to WHO nomenclature), located at the anterior aspect of the forearm. An electrical stimulation was delivered through the acupuncture needle at an intensity of 1 V, pulse width of 5 ms, and stimulation frequencies of 0.5, 1, 5, and 10 Hz in a random order. The duration of electroacupuncture was 6 min, during which blood pressure and heart rate responses were monitored.
RESULTS:
Group-averaged data indicated that 1-Hz electroacupuncture decreased blood pressure and heart rate. Blood pressure was significantly decreased from the prestimulation baseline value of 86.6 ± 2.9 to 81.4 ± 2.3 mmHg during 4-6 min of 1-Hz electroacupuncture (mean ± SE, P < 0.01). Heart rate was also significantly decreased (from 66.2 ± 2.0 to 62.7 ± 1.7 beats/min, P < 0.01).
CONCLUSIONS:
These results provide fundamental evidence that bradycardiac and depressor responses are effectively produced by electrical acupuncture in humans.
KEYWORDS:
Blood pressure; Electroacupuncture; Heart rate; Stimulation frequencies
PMID: 26695399