In a previous study, it was demonstrated, for the first time, that Phα1β has analgesic effect in rodent models of chronic and acute pain with a therapeutic index wider than ω-conotoxin MVIIA ( Souza et al., Selleckchem XAV 939 2008). The present work aimed to compare Phα1β with ω-conotoxin MVIIA and morphine as a new therapy for postoperative pain treatment in a mice model of pain. Additional investigation was performed comparing the cardiac, neurological and

immunogenic side effects induced by Phα1β, ω-conotoxin MVIIA and morphine in rats and human polymorph mononuclear cells. Phα1β was purified by a combination of gel filtration, reverse phase FPLC/FPLC and ion exchange HPLC, as previously described (Cordeiro Mdo et al., 1993). ω-Conotoxin MVIIA was purchased from Latoxan (Valence, France). Morphine sulfate was obtained from Cristália (Dimorf®, São Paulo, Brazil). The stock solutions of the toxins were prepared with phosphate buffer saline (PBS) in siliconized plastic tubes, maintained at −18 °C and diluted to the desired concentration just before

use. Morphine was dissolved in PBS on the same day of the experiment. Complete Freund’s adjuvant (1 mg/mL of heat killed Mycobacterium tuberculosis in 85% paraffin oil and 15% mannide monooleate), Ficoll/Hypaque gradient and RPMI-1640 medium were obtained from Sigma (St. Louis, MO, USA). Bovine fetal serum, l-glutamine and Cisplatin molecular weight antibiotics (penicillin/streptomicin) were obtained from GIBCO (Long Island, NY, USA). Anti-CD14-FITC were obtained from Caltag (Burlingame, CA, USA), anti-IL-1β, IL-6 and IL-10-PE were obtained from Biosciences (San Jose, CA, USA). The other reagents were of analytical grade. All experiments were carried out according to the current guidelines for the care of laboratory animals and ethical guidelines for investigations of experimental

pain in conscious animals (Zimmermann, 1983). They were authorized by the Ethics Committee of the Federal University of Minas Gerais (protocol number: 179/2006). Male adult Swiss mice (30–40 g) or Wistar rats (180–250 g) were kept in the home cage environment with free access to water and food. Room temperature was maintained at 22 ± 1 °C with a 12–12 h light-dark cycle. Intrathecal injection was performed in accordance with the method previously described (Hylden and Wilcox, 1980 and Mestre et al., 1994). Briefly, check details a volume of 5 μl for mice and 10 μl for rats was administered with a 28-gauge needle connected to a 10 μl Hamilton microsyringe, while the animal was lightly restrained to maintain the position of the needle. Puncture of the dura mater was indicated behaviorally by a slight flick of the tail. Behavioral evaluation was performed blindly with respect to drug administration. The incisional pain model was carried out according to the procedure described in rats (Brennan et al., 1996) and adapted to mice (Pogatzki and Raja, 2003). Mice were anesthetized with 2% halothane via a nose cone.