Klemn (1976) and Porro and Carli (1988) for rationale, technique, and species differences.
TI abolishes voluntary motor activity. Spinal reflexes are suppressed, but not abolished. Muscle tone varies with species and with the induction procedure. In rabbits, perhaps the most susceptible species, fine muscle tremors can occur initially or be induced by stimulation of the patellar tendon reflex. Rabbits' eyes remain open and fixed, but the corneal reflex is still present. Initially, the heart rate of immobilized animals can increase; at later stages, the rate tends to decrease. Fully immobilized rabbits exhibit pronounced catalepsy with reduced muscle tone.
In susceptible species, TI is relatively easy to achieve. A rabbit, for example, is grasped from behind around the neck at the base of the skull by one hand. With the other hand under the rump (and preventing kicking by the hind legs), the animal is turned over onto its back with one quick smooth motion while gentle traction is maintained on the neck. Gentle neck traction might stimulate receptors in the carotid body to play a role in the induction and maintenance of immobility. Rubbing the animal's abdomen and talking in a soft monotone are said to facilitate the reflex. An animal immobilized can commonly be left lying on its back for a short period without additional restraint. The reflex can last from a few seconds to several minutes; the period depends on the species, the animal, previous experience, and the time that the animal is held in the supine position. Gentle traction on its neck will continue maintenance of TI and its associated analgesia. Loud noises or sudden poking or probing of the animal will cause it to arouse.
TI is useful in performing physical examinations, deep abdominal palpation, and ophthalmologic examinations. It is readily reversible by returning the animal to its normal posture. After immobility is terminated, some degree of analgesia and disorientation can persist for a period that depends on the duration and depth of TI.
The use of acupuncture is limited primarily to the treatment of specific chronic, painful disorders (Klide, 1989; Klide and Martin, 1989). It has been used successfully in the management of chronic pain in horses and dogs. It is not curative, and it has to be repeated periodically to allow the animal mobility and comfort.
Acupuncture has been successful in modifying acute pain, but has no lingering effect on removal of the stimulation. It has been used for surgical analgesia under limited circumstances.