title: Analgesic effects of minodronate on formalin-induced acute inflammatory pain in rats.
abstract: Minodronate is expected to produce greater analgesic effects than other bisphosphonates. However, there are no studies comparing bisphosphonate analgesic effects on formalin-induced acute inflammatory pain in rats. The purpose of the present study was to evaluate the analgesic effects of minodronate, morphine, and placebo. Four-month-old female Wistar rats were administered minodronate (50 mg/kg), morphine (10 mg/kg), or vehicle (n = 10 each) injections. Thirty minutes later, all rats were injected with formalin (right hind paw) to induce acute inflammatory pain. Paw licking and lifting as indicators of nociceptive pain responses were monitored from 0 to 5 min (phase 1; chemical-stimulation state) and then from 10 to 30 min (phase 2; spinal-sensitized state) after injection. The percentage of limb usage of the formalin-injected and the non-injected sides were measured in phases 1 and 2 by counting foot stamps. Minodronate significantly decreased nociceptive responses and increased limb usage compared with vehicle in phase 2 only (P < 0.05). Morphine significantly decreased nociceptive responses and increased limb usage compared with minodronate and vehicle in both phase 1 and 2 (P < 0.05). In conclusion, minodronate showed significant analgesic effects for formalin-induced acute pain in the spinal-sensitized state.
authors.affiliation: Department of Orthopedic Surgery, Akita University Graduate School of Medicine, 1-1-1 Hondo, Akita 010-8543, Japan. tsegawa@doc.med.akita-u.ac.jp
authors.forename: Toyohito
authors.initials: T
authors.lastname: Segawa
authors.forename: Naohisa
authors.initials: N
authors.lastname: Miyakoshi
authors.forename: Yuji
authors.initials: Y
authors.lastname: Kasukawa
authors.forename: Hiroshi
authors.initials: H
authors.lastname: Aonuma
authors.forename: Hiroyuki
authors.initials: H
authors.lastname: Tsuchie
authors.forename: Yoichi
authors.initials: Y
authors.lastname: Shimada
mesh_terms: D059787:Acute Pain / Q000139:chemically induced / Q000188:drug therapy* / Q000523:psychology; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D000894:Anti-Inflammatory Agents, Non-Steroidal / Q000494:pharmacology*; D001522:Behavior, Animal / Q000187:drug effects; D004164:Diphosphonates / Q000494:pharmacology*; D005260:Female; D005557:Formaldehyde; D007093:Imidazoles / Q000494:pharmacology*; D009020:Morphine / Q000494:pharmacology; D059225:Nociception / Q000187:drug effects*; D010147:Pain Measurement; D051381:Rats; D017208:Rats, Wistar
chemical_list: D000701:Analgesics, Opioid; D000894:Anti-Inflammatory Agents, Non-Steroidal; D004164:Diphosphonates; D007093:Imidazoles; C087958:YM 529; D005557:Formaldehyde; D009020:Morphine