ABSTRACT
BACKGROUND/AIMS: Acidic saline injections produce mechanical hyperresponsiveness in male Sprague-Dawley rats. We investigated the effect of milnacipran in conjunction with tramadol on the pain threshold in an acidic saline animal model of pain. METHODS: The left gastrocnemius muscle of 20 male rats was injected with 100 microL of saline at pH 4.0 under brief isoflurane anesthesia on days 0 and 5. Rats administered acidic saline injections were separated into four study subgroups. After determining the pre-drug pain threshold, rats were injected intraperitoneally with one of the following regimens; saline, milnacipran alone (60 mg/kg), milnacipran (40 mg/kg) plus tramadol (20 mg/kg), or milnacipran (40 mg/kg) plus tramadol (40 mg/kg). Paw withdrawal in response to pressure was measured at 30 min, 120 min, and 5 days after injection. Nociceptive thresholds, expressed in grams, were measured with a Dynamic Plantar Aesthesiometer (Ugo Basile, Italy) by applying increasing pressure to the right or left hind paw until the rat withdrew the paw. RESULTS: A potent antihyperalgesic effect was observed when tramadol and milnacipran were used in combination (injected paw, p=0.001; contralateral paw, p=0.012). This finding was observed only at 30 min after the combination treatment. CONCLUSIONS: We observed potentiation of the antihyperalgesic effect when milnacipran and tramadol were administered in combination in an animal model of fibromyalgia. Further research is required to determine the efficacy of various combination treatments in fibromyalgia in humans.
Subject(s)
Animals , Male , Rats , Analgesics, Opioid/administration & dosage , Antidepressive Agents/administration & dosage , Behavior, Animal/drug effects , Cyclopropanes/administration & dosage , Disease Models, Animal , Drug Synergism , Drug Therapy, Combination , Fibromyalgia/chemically induced , Hydrogen-Ion Concentration , Hyperalgesia/etiology , Injections, Intraperitoneal , Pain/etiology , Pain Measurement , Pain Threshold/drug effects , Rats, Sprague-Dawley , Sodium Chloride , Time Factors , Tramadol/administration & dosageABSTRACT
La alopécia areata (AA) es una patología realtivamente frecuente del folículo piloso. Su etiología, si bien es desconocida, probablemente corresponda a un fenómeno autoinmune, aunque factores genéticos y ambientales también estarían involucrados. La inmunoterapia tópica es la modalidad terapéutica más efectiva y aceptada en el tratamiento de la AA crónica severa. La inmunoterapia tópica se define como la inducción y posterior provocación periódica de una dermatitis de contacto alérgica, a través de la aplicación de un potente alergeno de contacto en una zona cutánea determinada. Han sido utilizados tres alergenos de contacto en el tratamiento de la alopecia areata: dinitroclorobenceno (DNCB), dibutil éster del ácido escuárico (SADBE) y difenciprona (DPC). En el presente trabajo se describen las principales características de estos agentes tópicos