Interest in the scientific basis of acupuncture has been increasing, as reflected by a dramatic rise in the number of scientific publications on medical and veterinary acupuncture. The mechanism of action remains unclear because it is not only one. Activation of the descending pain inhibitory system with spinal and supraspinal endorphin release as well as the involvement of other neurotransmitters like serotonin and norepinephrine have been analyzed. Acupuncture triggers a sequence of events involving the release of central endogenous opioid-like substances, as well as ACTH, vasopressin and cortisol, which modulate signals processed along the pathway and have effects on the immunoinflammatory response, the hypothalamic-pituitary axis and homeostasis. Central nervous system imaging techniques allow evaluate the events that occur after acupuncture-induced stimulation, including spinal gating and descending inhibitory pathways. The limbic system and thalamus play an important role in acupuncture-induced analgesia. Cortical somatosensory-evoked potentials have provided compelling evidence for the hypothesis that peripheral driver stimulation is the key element in producing propagated sensations along the meridians. Acupuncture has both local and distant analgesic effects that may be mediated by different mechanisms. The acupuncture points traditionally used for the treatment have a neuroanatomical significance from the viewpoint of western medicine; from that one can hypothesizes a plausible mechanism of action as to how acupuncture achieves its therapeutic effects in terms of contemporary western medicine.

La acupuntura es una de las modalidades terapéuticas últimamente más estudiadas y documentadas en el campo de la medicina y la veterinaria. El mecanismo de acción de la acupuntura ha resultado controvertido durante bastante tiempo por el intento de identificación de un proceso único. La estimulación con acupuntura de las fibras nerviosas periféricas envía impulsos a la médula espinal y activa varios centros en el cerebro, para liberar neurotransmisores que ejercen un efecto homeostático en todo el cuerpo. Modula la actividad neural en el diencéfalo, que ejerce influencia en las funciones autonómica, endocrina e inmune a través del eje hipotálamo-hipófisis-adrenal, regulando la liberación circadiana de ACTH, vasopresina y cortisol, conduciendo igualmente a la homeostasis. Los estudios por imagen han mostrado que la estimulación por acupuntura activa estructuras de inhibición descendente del dolor, demostrando que la acupuntura asume una vía central en el control del dolor. Igualmente, la acupuntura actúa sobre el sistema límbico y la integración talámica. Los potenciales evocados corticales somatosensoriales han mostrado que los canales de acupuntura son pasajes bioeléctricos que permiten la transmisión de impulsos. Diversos mecanismos locales de acción explican algunos de los efectos de la acupuntura. Es preciso estudiar si el genotipo y la influencia de factores ambientales ejercen una influencia importante en predecir qué pacientes serán beneficiados por la terapia acupuntural.

OBJETIVO: Avaliar os possíveis efeitos benéficos da eletroacupuntura em ratos submetidos à anestesia intraperitoneal (i.p.) com ketamina / xilazina. MÉTODOS: Quarenta e oito ratos Wistar foram randomizados em quatro grupos iguais. Todos os ratos receberam injeções i.p. de ketamina (90 mg / kg) + xilazina (10 mg / kg). Os ratos do grupo Valores Basais (controle - BV) não receberam nenhum tratamento adicional. Os acupontos equivalentes aos humanos E-36 (Zusanli) e VC-12 (Zhongwan) foram escolhidos para inserção de agulhas e estimulação elétrica. Os ratos do grupo AC foram estimulados com agulhas esterilizadas descartáveis, de aço inoxidável, nos acupontos E-36 direito e VC12. As agulhas foram mantidas por 30 minutos. Nos ratos do grupo EAC10, após agulhamento, como descrito, eletrodos foram conectados às agulhas e ao eletro-estimulador modelo NKL EL-608 e aplicadas ondas quadradas pulsantes, 10 Hz, 10 mA, por 30 minutos. Os ratos do grupo EAC100 foram submetidos à EA como descrito. No entanto, uma maior freqüência (100 Hz) foi utilizada. RESULTADOS: Trinta e sete ratos permaneceram no nível anestésico adequado durante o experimento. No entanto, a manutenção da anestesia foi se fez necessária em 11 animais. Nos ratos do grupo EAC100 a necessidade de anestesia complementar diminuiu para 9,1% em comparação com ratos do grupo BV (36,3%). CONCLUSÃO: Tanto a AC como a EAC10/100 prolongam o efeito anestésico da combinação ketamina-xilazina em ratos, permitindo maior duração da anestesia com menor dose de anestésico, reduzindo assim a ocorrência de complicações.

PURPOSE: To evaluate the possible beneficial effects of electro-acupuncture in rats subjected to ketamine/xylazine (KX) intra-peritoneal (i.p.) anesthesia. METHODS: Forty-eight male Wistar rats were distributed in four equal groups. All rats received i.p. injections of ketamine (90 mg/kg) +xylazine (10 mg/kg) anesthesia. Basal values group (control) rats (BV) received no additional treatment. The equivalent of the human right ST36 (Zusanli) and CV-12(Zhongwan) acupoints were chosen for needling and electrical stimulation. AC rats were needled with sterilized disposable stainless steel needles at right ST36 and CV12 acupoints; needles were retained for 30 minutes. EAC10 rats, after needle insertion as described, had electrodes connected to both needles and to an electro stimulator model NKL EL-608; pulsed square waves, 10 Hz, 10 mA, was applied for 30 minutes. EAC100 rats were submitted to EA as described. However, a greater frequency (100 Hz) was used. RESULTS: Thirty-seven rats remained under adequate anesthetic level during the experiment. However, maintenance anesthesia was required by 11 rats. Need for additional anesthesia decreased to 9.1% in EAC100 rats compared to BV (36.3%). CONCLUSION: Both the AC and the EAC10/100 prolong the anesthetic effect of the combination Ketamine-xylazine in rats, allowing longer duration of anesthesia with a lower dose of anesthetic, thereby reducing the occurrence of complications.