Involvement of the mechanoreceptors in the sensory mechanisms of manual and electrical acupuncture.

I bring this study to your attention for a few reasons.
1. I really like studies that get down to the real nitty gritty of the mechanisms behind acupuncture and what is really happening on a tissue level. To actually ask the question of whether manual and electro acupuncture use the same receptor is something I wouldn't have really thought about, and the answer is interesting to me. They do use the same receptor.
2. This study is out of the Cardiology Department at the University of Kinki in Japan. So they thought enough of it to fund the study.
3. Even in anesthetized rats, the depressor and bradycardic response was quite pronounced and statistically significant. This falls into the category "So there! Placebo skeptics!"
4. They used hindleg points to study the depressor response. This would not be the point selection I would have used, so am curious why they chose those points and what their corollary would be in a human subject.
5. I had no idea that there was a specific mechanoreceptor blocker, gadolinium.

What do you readers think of this study?
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Involvement of the mechanoreceptors in the sensory mechanisms of manual and electrical acupuncture.
Auton Neurosci. 2011 Feb 24;160(1-2):27-31. Epub 2010 Dec 16.
Yamamoto H, Kawada T, Kamiya A, Miyazaki S, Sugimachi M.
Source
Division of Cardiology, Department of Medicine, Faculty of Medicine, Kinki University, Osaka, Japan. hiromi@med.kindai.ac.jp
Abstract

The modalities of acupuncture can be broadly classified into manual acupuncture (MA) and electroacupuncture (EA). Although MA has been reported to cause winding of tissue around the needle and subsequent activation of the sensory mechanoreceptors and nociceptors, the sensory mechanisms of acupuncture stimulation are not fully understood. To test the hypothesis that the involvement of the mechanoreceptors in the sensory mechanism is different in MA and EA, we examined the effects of a stretch-activated channel blocker gadolinium on the hemodynamic responses to hind limb MA and EA in anesthetized rats (n = 9). Gadolinium significantly attenuated the MA-induced bradycardic response (-22 ± 5 vs. -10 ± 3 bpm, P<0.05) and tended to attenuate the MA-induced depressor response (-30 ± 5 vs. -18 ± 4 mmHg, P = 0.06). On the other hand, gadolinium significantly attenuated both the EA-induced bradycardic (-22 ± 5 vs. -9 ± 4 bpm, P<0.01) and depressor responses (-32 ± 6 vs. -15 ± 5 mmHg, P<0.01). These results indicate that the mechanoreceptors are involved in the sensory mechanisms for both MA and EA.

Acupuncture in critically ill patients improves delayed gastric emptying: a randomized controlled trial.

This article combines my previous specialty, Anesthesiology and Critical Care, and Acupuncture. So for me it is doubly interesting. In addition, the results are dramatic in this study coming out of Germany, with collaboration with colleagues at Harvard. The acupuncture improved gastric emptying much more than medications, by a large margin. We don't get that kind of margins often in acupuncture research, so it's a satisfying study.
(For more information about my practice please click here.)
Acupuncture in critically ill patients improves delayed gastric emptying: a randomized controlled trial.
Pfab F, Winhard M, Nowak-Machen M, Napadow V, Irnich D, Pawlik M, Bein T, Hansen E.
Anesth Analg. 2011 Jan;112(1):150-5. Epub 2010 Nov 16

Department of Anesthesiology, University Hospital Regensburg, Regensburg, Germany.
Abstract
BACKGROUND:

Malnutrition remains a severe problem in the recovery of critically ill patients and leads to increased in-hospital morbidity and in-hospital stay. Even though early enteral nutrition has been shown to improve overall patient outcomes in the intensive care unit (ICU), tubefeed administration is often complicated by delayed gastric emptying and gastroesophageal reflux. Acupuncture has been successfully used in the treatment and prevention of perioperative nausea and vomiting. In this study we evaluated whether acupuncture can improve gastric emptying in comparison with standard promotility drugs in critically ill patients receiving enteral feeding.
METHODS:
Thirty mechanically ventilated neurosurgical ICU patients with delayed gastric emptying, defined as a gastric residual volume (GRV) >500 mL for ≥ 2 days, were prospectively and randomly assigned to either the acupoint stimulation group (ASG; bilateral transcutaneous electrical acupoint stimulation at Neiguan, PC-6) or the conventional promotility drug treatment group (DTG) over a period of 6 days (metoclopramide, cisapride, erythromycin). Patients in the ASG group did not receive any conventional promotility drugs. Successful treatment (feeding tolerance) was defined as GRV <200 mL per 24 hours.
RESULTS:
.. After 5 days of treatment, 80% of patients in the ASG group successfully developed feeding tolerance versus 60% in the DTG group. On treatment day 1, GRV decreased from 970 ± 87 mL to 346 ± 71 mL with acupoint stimulation (P = 0.003), whereas patients in the DTG group showed a significant increase in GRV from 903 ± 60 mL to 1040 ± 211 mL (P = 0.015). In addition, GRV decreased and feeding balance (defined as enteral feeding volume minus GRV) increased in more patients in the ASG group (14 of 15) than in the DTG group (7 of 15; P = 0.014). On treatment day 1, the mean feeding balance was significantly higher in the ASG group (121 ± 128 mL) than in the DTG group (-727 ± 259 mL) (P = 0.005). Overall, the feeding balance improved significantly on all days of treatment in comparison with the DTG group. Patients in the DTG group did not show an increase in feeding balance until day 6.
CONCLUSIONS:

We introduce a new protocol for acupuncture administration in the critical care setting. We demonstrated that this protocol was more effective than standard promotility medication in the treatment of delayed gastric emptying in critically ill patients. Acupoint stimulation at Neiguan (PC-6) may be a convenient and inexpensive option (with few side effects) for the prevention and treatment of malnutrition in critically ill patients.