title: The formalin test in the naked mole-rat (Heterocephalus glaber): analgesic effects of morphine, nefopam and paracetamol.
abstract: The present experiments were initiated to study the effects of morphine, nefopam and paracetamol in the naked mole-rat, a hairless rodent that lives in subterranean colonies of up to 300, following the inability to demonstrate morphine analgesia in the hot-plate test in the rodent. The formalin test was used. Injection of 20 microliters 10% formalin produced two periods of high licking and pain behaviour, the early (0-5 min) and the late phase (15-60 min). Morphine (10 or 20 mg/kg), nefopam (10 or 20 mg/kg) and paracetamol (200 mg/kg) significantly inhibited the two phases. Paracetamol (400 mg/kg) produced significant analgesia only during the late phase. It is concluded that, unlike in the hot-plate test, it is possible to demonstrate the analgesic effects of morphine in the naked mole-rat, in the formalin test.
authors.affiliation: Department of Animal Physiology, University of Nairobi, Kenya.
authors.forename: T I
authors.initials: TI
authors.lastname: Kanui
authors.forename: F
authors.initials: F
authors.lastname: Karim
authors.forename: P K
authors.initials: PK
authors.lastname: Towett
mesh_terms: D000082:Acetaminophen / Q000494:pharmacology*; D000700:Analgesics / Q000494:pharmacology*; D000704:Analysis of Variance; D000818:Animals; D004305:Dose-Response Relationship, Drug; D005557:Formaldehyde; D009020:Morphine / Q000494:pharmacology*; D009340:Nefopam / Q000494:pharmacology*; D009619:Nociceptors / Q000187:drug effects / Q000502:physiology; D010146:Pain / Q000188:drug therapy / Q000503:physiopathology*; D012377:Rodentia
chemical_list: D000700:Analgesics; D005557:Formaldehyde; D000082:Acetaminophen; D009340:Nefopam; D009020:Morphine