Effects of Naloxone on Opioid-induced Hyperalgesia and Tolerance to Remifentanil under Sevoflurane Anesthesia in Rats

Abstract

An ultra-low dose of naloxone blocked remifentanil-induced hyperalgesia but did not change opioid tolerance under inhalant anesthesia. Moreover, the MAC increase associated with hyperalgesia was also blocked by naloxone.

The Effects of the Toll-Like Receptor 4 Antagonist, Ibudilast, on Sevoflurane’s Minimum Alveolar Concentration and the Delayed Remifentanil-Induced Increase in the Minimum Alveolar Concentration in Rats

“…5 The naloxone dose was selected based on its ability to block opioid-induced hyperalgesia in rats. 6,22 Ibudilast (100 mg, TCI Europe N.V., Amsterdam, the Netherlands) was dissolved in 2% Tween and 20% phosphate-buffered saline at 5 mg/mL. Remifentanil (Ultiva) was obtained from Glaxo-Smith-Kline (Madrid, Spain), naloxone was obtained from Kern Pharma (Terrasa, Spain), and sevoflurane (Sevorane) was obtained from Abbott Laboratories (Madrid, Spain).…”

“…[11][12][13] Interestingly, the opioid antagonist and also toll-like receptor 4 (TLR4) antagonist, naloxone, may block remifentanil-induced hyperalgesia and the associated increase in anesthetic requirements (MAC) 6 in the naive nonoperated rat. Ibudilast (AV-411) is a nonselective phosphodiesterase inhibitor and TLR4 receptor antagonist.…”

“…6 This is determined by measuring the reduction in the minimum alveolar concentration (MAC) produced by analgesics and is considered an indirect, although clinically valuable, method of determining analgesic potency during the intraoperative period.…”

CaMKII Phosphorylation in Primary Somatosensory Cortical Neurons is Involved in the Inhibition of Remifentanil-induced Hyperalgesia by Lidocaine in Male Sprague-Dawley Rats

“…1,2 Our previous studies reported that remifentanil-induced hyperalgesia could be suppressed by the systemic application of lidocaine, but the underlying mechanisms remain incompletely understood. 2 Here, using a rat model, we explored the role of the primary somatosensory (S1) cortex in remifentanilinduced hyperalgesia as well as its inhibition by lidocaine.…”

Does perioperative opioid infusion increase postoperative opioid requirement?

“…They are also widely used during the intraoperative period as they reduce the need for inhalational anesthetic agents. [1] However, perioperative opioid infusion is accused to result in acute opioid tolerance as the postoperative opioid requirement increases in time to provide efficient analgesia. It comes out as a decrease in drug efficacy.…”