The effect of meperidine on thermoregulation in mice: involvement of alpha2-adrenoceptors.
Meperidine has potent antishivering properties. The underlying mechanisms are not fully elucidated, but recent investigations suggest that alpha2-adrenoceptors are likely to be involved. We performed the current study to investigate the effects of meperidine on nonshivering thermogenesis in a model of thermoregulation in mice. After injection (0.1 mL/kg intraperitoneally) of saline, meperidine (20 mg/kg), the specific alpha2-adrenoceptor antagonist atipamezole (2 mg/kg), plus saline or atipamezole plus meperidine, respectively, mice were positioned in a Plexiglas chamber. Rectal temperature and mixed expired carbon dioxide were measured after provoking thermoregulatory effects by whole body cooling. Maximum response intensity of nonshivering thermogenesis and the thermoregulatory threshold for nonshivering thermogenesis, which was defined as the temperature at which a sustained increase in expiratory carbon dioxide can be measured, were investigated. Meperidine significantly decreased the threshold of nonshivering thermogenesis (36.6 degrees C +/- 0.7 degrees C) versus saline (37.9 degrees C +/- 0.6 degrees C) and versus atipamezole plus saline (37.8 degrees C +/- 0.4 degrees C; P <0.01). This effect was abolished after administration of meperidine combined with atipamezole (37.7 degrees C +/- 0.6 degrees C; P <0.05). Meperidine did not decrease the maximum intensity of nonshivering thermogenesis. The results suggest a major role of alpha2-adrenoceptors in the inhibition of thermoregulation by meperidine in mice.
Paris
Andrea
A
Department of Anaesthesiology and Intensive Care Medicine, University Hospital Schleswig-Holstein, Campus Kiel, Kiel, Germany; *Department of Anesthesia, University of California, San Francisco, California.
Ohlendorf
Christina
C
Marquardt
Michael
M
Bein
Berthold
B
Sonner
James M
JM
Scholz
Jens
J
Tonner
Peter H
PH
D000317:Adrenergic alpha-Antagonists / Q000494:pharmacology; D000701:Analgesics, Opioid / Q000494:pharmacology*; D000818:Animals; D001833:Body Temperature Regulation / Q000187:drug effects*; D002245:Carbon Dioxide / Q000378:metabolism; D007093:Imidazoles / Q000494:pharmacology; D008297:Male; D008614:Meperidine / Q000494:pharmacology*; D051379:Mice; D018341:Receptors, Adrenergic, alpha-2 / Q000187:drug effects*; D013696:Temperature; D022722:Thermogenesis / Q000187:drug effects
D000317:Adrenergic alpha-Antagonists; D000701:Analgesics, Opioid; D007093:Imidazoles; D018341:Receptors, Adrenergic, alpha-2; C050701:atipamezole; D002245:Carbon Dioxide; D008614:Meperidine