| dc.description.abstract | The aim of the present study was to investigate the effect of
commonly used analgesic and anti-inflammatory drugs in the naked
mole-rat. Two centrally acting narcotic analgesics (pethidine
hydrochloride and codeine phosphate). two non-steroidal
antiinflammatory drugs (acetylsalicylic acid and naproxen) and two
steroidal antiinflammatory drugs (hydrocortisone sodium succinate
and dexamethasone phosphate) were used. The animals were kept
under controlled laboratory conditions.
The formalin test was performed by injecting a dilute solution
of formalin (20 ul of 10% formalin) subcutaneously in the right
hind paw of both control and test animals. Two parameters, the
number of licks and the time spent licking the paw (sec) were
monitored in blocks of 5 min for either 1 h or 2 h. The vehicle or
drug were inj ected 30 min prior to the formalin test.
The injection of dilute formalin produced two periods of pain
behaviour characterized by licking and biting of the injected paw,
the early (0-5 min) and the late (25-60 min) phase. Pethidine (20
or 30 mg/kg) and codeine (10, 25 or 50 mg/kg) significantly
reduced licking activity in a dose-dependent manner, in both the
early and late phase. In addition, pethidine and codeine
administration also induced agonistic, hypersensitive, hyperactive
behaviour and motor impairment that was naloxone (2 mg/kg)
reversible. Acetylsalicylic acid (400 or 600 mg/kg), naproxen (200
mg/kg). hydrocortisone (75 or 150 mg/kg) and dexamethasone
(30 mg/kg) significantly reduced licking and pain related activity
in a dose-dependent manner but in the late phase only.
It is concluded that the naked mole-rat has anti-nociceptive
systems that can be activated by administration of the narcotic and
non-narcotic drugs used. It appears that the opioid system. in the
naked mole-rat is more involved in the regulation of agonistic and
motor behaviour. than anti-nociception. | en |
