Related Experiment Video
Updated: Jul 2, 2026

Assessment of Morphine-induced Hyperalgesia and Analgesic Tolerance in Mice Using Thermal and Mechanical Nociceptive Modalities
Published on: July 29, 2014
Magnesium ions and opioid agonist activity in streptozotocin-induced hyperalgesia
Magdalena Bujalska1, Ewelina Malinowska, Helena Makulska-Nowak
1Department of Pharmacodynamics, Medical University of Warsaw, Warsaw, Poland. mbujalska@gmail.com
Abstract:
Streptozotocin-induced hyperglycemia accompanied by a chronic decrease in the nociceptive threshold is considered a useful model of experimental hyperalgesia. We examined (1) the effect of the opioid receptor agonists and (2) the effect of the magnesium ions (Mg(2+)) on the antinociceptive action of opioid agonists in a diabetic neuropathic pain model. When administered alone, opioid agonists like morphine (5 mg/kg i.p.) and fentanyl (0.0625 mg/kg i.p.), as well as the partial agonist buprenorphine (0.075 mg/kg) had only little effect on streptozotocin-induced hyperalgesia. However, pretreatment with Mg(2+) at a dose of 40 mg magnesium sulfate/kg i.p. markedly enhanced the analgesic activity of all three investigated opioids. Practical aspects of co-administration of magnesium and opioids in diabetic neuropathy are discussed.
Related Concept Videos
Analgesia and Pain Management
Opioid Receptors: Overview
Opioid Analgesics: Synthetic and Semisynthetic Opioids
Opioid Analgesics: Morphine and Other Natural Cogeners
Ligand-Gated Ion Channel Receptor: Gating Mechanism
Nociception

