El dolor tiene dos aspectos fundamentales, el sensorial discriminativo (es decir localización, tipo, intensidad, y otras características sensitivas), y el emocional afectivo (el sufrimiento que origina el dolor). En un estudio efectuado en Maryland, EEUU, estudiaron los efectos de la electroacupuntura sobre la respuesta afectiva inducida por el dolor. Aparentemente la dimensión afectiva tiene mecanismos diferentes que la sensorial, de hecho, la localización de la actividad en la corteza del cíngulo revela que son localizaciones diferentes. Para demostrarlo utilizaron un modelo experimental en ratas que se explica a continuación en el abstract. Muy reciente, actual, y publicado en un revista de impacto.
Electroacupuncture alleviates affective pain in an inflammatory pain rat model.
Source
Center for Integrative Medicine, School of Medicine, University of Maryland, 520 W. Lombard Street, Baltimore, MD, 21201, USA; Department of Neurobiology, Shanxi Medical University, Taiyuan, 030001, Shanxi, PR China.
Abstract
Pain has both sensory-discriminative and emotional-affective dimensions. Previous studies demonstrate that electroacupuncture (EA) alleviates the sensory dimension but do not address the affective. An inflammatory pain rat model, produced by a complete Freund adjuvant (CFA) injection into the hind paw, was combined with a conditioned place avoidance (CPA) test to determine whether EA inhibits spontaneous pain-induced affective response and, if so, to study the possibility that rostral anterior cingulate cortex (rACC) opioids underlie this effect. Male Sprague-Dawley rats (250-275 g, Harlan) were used. The rats showed place aversion (i.e. affective pain) by spending less time in a pain-paired compartment after conditioning than during a preconditioning test. Systemic non-analgesic morphine (0.5 and 1.0 mg/kg, i.p.) inhibited the affective reaction, suggesting that the affective dimension is underpinned by mechanisms different from those of the sensory dimension of pain. Morphine at 0.5 and at 1 mg/kg did not induce reward. Rats given EA treatment before pain-paired conditioning at GB 30 showed no aversion to the pain-paired compartment, indicating that EA inhibited the affective dimension. EA treatment did not produce reward or aversive effect. Intra-rACC administration of D-Phe-Cys-Tyr-D-Trp-Orn-Thr-Pen-Thr amide (CTOP), a selective mu opioid receptor antagonist, but not norbinaltorphimine (nor-BNI), a selective kappa opioid receptor antagonist, blocked EA inhibition of the affective dimension. These data demonstrate that EA activates opioid receptors in the rACC to inhibit pain-induced affective responses and that EA may be an effective therapy for both the sensory-discriminative and the affective dimensions of pain.
© 2011 European Federation of International Association for the Study of Pain Chapters
Acupuntura Médica Sabadell 