acupuncture & blood flow

Needle stimulation into the anterior tibial muscle in healthy female subjects increases both

skin and muscle blood flow.

release of CGRP was suggested to be involved in the mechanisms of blood flow increase.

Recently, by using invasive laser Doppler flowmetry, muscle blood flow was shown to increase after electrical stimulation of dorsal roots and electroacupuncture-like stimulation to the hindpaw in anaesthetised rats (Noguchi et al 1999; Sato et al. 2000). Sato et al. (2000) concluded that antidromic vasodilatation in skeletal muscle for 3–15 min following 30 s of stimulation of group IV afferent fibres in dorsal roots is mediated by the release of CGRP from afferent nerve terminals.

There was a relationship between blood flow increases and intensity of the stimuli, the

DeQi stimulation leading to the largest increases and also being rated as the most painful

mode of needle stimulation. The noxious mode of stimulation and the long-lasting effects

on blood flow indicate vasodilative substances, such as CGRP, from sensory nerve terminals

being involved in the mechanisms (Jänig and Lisney 1989; Kashiba and Ueda 1991; Häbler

et al.1997; Sato et al. 2000). The mostly non-painful SF stimulation may be too weak to induce

the release of vasoactive substances, albeit a tendency to increase in muscle blood flow was

found for a few minutes.

Interactions with sympathetic neurones of the needling must also be considered in the

mechanisms of blood flow changes (Ernst and Lee 1985; Andersson and Lundeberg 1995;

Sugiyama et al. 1995; Sato et al. 1997; Häbler et al. 1997; Sato et al. 2000). However, since

effects of sympathetic neurones on blood flow are triggered quickly and are suggested to

outlast the stimulation with a few seconds only, such effects are likely to be hidden by the

more powerful effects of vasodilative substances induced by the needling (Ernst and Lee

1986; Sugiyama et al. 1995; Häbler et al. 1997).