title: Unilateral hot plate test: a simple and sensitive method for detecting central and peripheral hyperalgesia in mice.
abstract: The application of thermal noxious stimuli forms the basis of some widely used tests to detect either hyperalgesic or analgesic reactions. In the classical hot plate test, mice react by licking their paws and/or jumping. However, tests relying on the unilateral application of thermal radiant heat to the plantar side of the hindpaw, have become popular in recent years since unilateral changes in nociceptive sensitivity can be detected. Based on the aforementioned tests, we developed a testing procedure in mice, the unilateral hot plate (UHP): the plantar side of one hindpaw is placed on a hot plate surface and, thus, the withdrawal latency of each paw can be measured separately. The effectiveness of several analgesic and hyperalgesic drugs measured by the UHP was compared with that measured by a method based on the application of radiant heat (RH) stimuli. In the UHP method, morphine (1-10 mg/kg) increases latencies, while spinal NMDA (0.001-1 ng) or PGE2 (30-300 ng), intraplantar carrageenan (2 - 4%) or PGE2 (30-300 ng) decrease latencies. In all cases, the UHP method detected changes in pain reactivity at lower doses than the RH test. The sensitivity and usefulness of the UHP test for performing pain studies in mice is described.
authors.affiliation: Laboratorio de Farmacología, Facultad de Medicina, Instituto Universitario de Oncología del Principado de Asturias (IUOPA), Universidad de Oviedo, C/Julián Clavería 6, E-33006 Oviedo, Spain.
authors.forename: Luis
authors.initials: L
authors.lastname: Menéndez
authors.forename: Ana
authors.initials: A
authors.lastname: Lastra
authors.forename: Agustín
authors.initials: A
authors.lastname: Hidalgo
authors.forename: Ana
authors.initials: A
authors.lastname: Baamonde
mesh_terms: D000701:Analgesics, Opioid / Q000627:therapeutic use; D000818:Animals; D002493:Central Nervous System Diseases / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D015232:Dinoprostone / Q000627:therapeutic use; D018690:Excitatory Amino Acid Agonists / Q000008:administration & dosage / Q000627:therapeutic use; D007839:Functional Laterality / Q000502:physiology*; D006358:Hot Temperature; D006930:Hyperalgesia / Q000175:diagnosis* / Q000188:drug therapy; D007274:Injections, Intraperitoneal; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D009020:Morphine / Q000627:therapeutic use; D016202:N-Methylaspartate / Q000008:administration & dosage / Q000627:therapeutic use; D010147:Pain Measurement / Q000187:drug effects / Q000379:methods*; D010523:Peripheral Nervous System Diseases / Q000175:diagnosis* / Q000188:drug therapy / Q000503:physiopathology; D011930:Reaction Time / Q000187:drug effects / Q000502:physiology*
chemical_list: D000701:Analgesics, Opioid; D018690:Excitatory Amino Acid Agonists; D016202:N-Methylaspartate; D009020:Morphine; D015232:Dinoprostone