Acupuncture: The science behind the practice (Proceedings)
Acupuncture is still regarded with skepticism by many veterinarians, or viewed as adjunct therapy rather than a primary therapy. It is especially useful for chronic conditions, and for some where there is no good solution in Western Medicine.
Evidence for acupuncture points
First, is there such a thing as an acupuncture point? Some studies have shown that merely placing a needle in the skin can cause some of the effects of acupuncture, though to a lesser extent. Vasodilation and subsequent feelings of heat are present when any skin is punctured with an acupuncture needle. Anyone who has observed reactions from a splinter will not be surprised at this research.There is no one single anatomical structure that can be identified as an acupuncture point. However, there are a number of things most points have in common. Two of the most common anatomical structures are:
Free nerve endings as part of a neurovascular bundle, wrapped in connective tissue sheath.
Holes: where cutaneous nerves emerge from deep fascia, or from bony foramina, or penetration of deep fascia by bundles of nerves and vessels
One of the more compelling points of evidence is the decreased electrical resistance of the skin over acupuncture points (in 50% of points in people, 79% in dogs in one study), using a "point finder", or ohmmeter with a sensitivity of millivolts and microamps. Some studies have found no difference. Discrepancies can arise from: the sensitivity (or lack thereof) of the point finder, the measuring technique used (pressing too hard/not hard enough, and too little differentiation of areas), the physiologic state of the animal (damp skin lowers skin resistance so a sweaty horse can appear to have points all over the body), and the environment (humid vs dry).
Injection of local anesthetic into acupoints before electroacupuncture abolishes the analgesic effect.
In about 1% of sport horses, there is a pilomotor reaction along the bladder meridian during acupuncture: it starts a few minutes after needle insertion, at maximum 10 minutes after needle insertion. Hair is raised in small clumps at acupuncture points.
Analgesic effects have been attributed to a placebo effect in humans, or to wanting to believe their dog is better. There are 5 exam rooms in my practice, and I primarily use one. Often, if owners try to take their dog to another room, the dog will try to pull them into my primary exam room. More than once, I have had aggressive or painful dogs and cats that begin their first treatment by trying to bite and claw me, and end up with tail-wagging sessions. The most dramatic was Guido, aptly-named German shepherd cross who tried to attack on the first visit, and on the second visit gazed into my eyes while wagging his tail, then turned around and sat on my feet.
Neurophysiologic basis for acupuncture points
Segmental analgesia: gate theory
Endogenous opioids are found in the CSF and brain and spinal cord tissue after acupuncture: met- and leu-enkephalin in brain, beta endorphin in brain and CSF, dynorphin and enkephalins in spinal cord increase with acupuncture.
Serotonin is also released with acupuncture. If you block serotonin, endorphins increase and vice versa. With acupuncture, if you block one or the other, there is a moderate decrease in analgesia. Blocking both results in a profound decrease in acupuncture analgesia.
Analgesia from acupuncture is blocked by naloxone. Anticholinergics decrease acupuncture analgesia. Parasympathomimetics increase it.
Needling causes vasodilation and measurable increase in skin temperature.
Beware of Chinese studies published in 1960's and 1970's (political situation=tell politicians what they want to hear).
• Humans: twice as effective as piroxicam.