Eletroacupuncture Analgesia in Dogs: Is There a Difference Between Uni or Bilateral Stimulation?

摘要

Acupuncture is an ancient art of Chinese medicine able to produce analgesia, mainly when electroacupunture (EA) is used. The study aimed to investigate the analgesic, cardiorespiratory, behavioral and endocrine effects of electrical stimulation of acupoints, comparing with false points and a control group. Eight clinically healthy adult dogs (7 females and one male) weighing 13+4 kg were submitted to four different treatments: Gfalse (n=8): electroestimulation of false acupoints; G-EA/bil (n=8): EA in stomach 36 (St 36), gall bladder 34 (GB 34) and spleen 6 (Sp 6), bilaterally; G-EA/uni (n=8): as G-EA/bil but unilaterally. An alternate square wave dense disperse (10-1000 Hz) electrical stimulus was applied after sedation of all animals with 0.05 mg/kg of acepromazine IV. The following measurements were performed: heart rate, pulse oxymetry, indirect arterial blood pressure, respiratory rate, EtCOz, rectal temperature and plasma cortisol concentration. Analgesia was investigated by the response to thermical and mechanical stimuli applied at the cutaneous region of the thorax and abdmonen and graded from 0 = no response, 1= slow response, 2 = quick and aggressive response. The thermical stimulus was also applied to the interdigital space of the anterior limbs, measuring the time in seconds until reaction. Visceral analgesia was evaluated by introducing a Foley catheter via rectus and inflating the cuff to a maximum volume of 60 ml. Behavior was also observed. Analysis of variance for repeated measures was used followed by Tukey's test. There were no important cardiorespiratory differences either in time in each group or among the groups. The cutaneous pain threshold was higher after bilateral and unilateral EA compared to false points, however thelatency period was shorter and analgesia was more intense and longer in the first group. Seventy five percent of the animals treated with both uni and bilateral EA were calm during treatment and 62,5% of the animals treated with false points showed signs of restlessness. Time to response to interdigital thermic stimulation was longer in bilateral EA group compared to the other groups. There was no difference in visceral response among the groups, but the animals undergoing bilateral EA supported greater volumes of air. There was no difference in plasma cortisol concentrations. Bilateral electrical stimulation of St 36, GB 34 and Sp 6 acupoints produced a shorter latency period, a greater intensity and longer duration of analgesia, than unilateral stimulation. EA did not produce stress response as there were no cardiorespiratory and cortisol changes during treatments. Electrical stimulation of false points did not produce any effect, suggesting that it is necessary to stimulate real acupoints to induce analgesia in dogs.