Unresponsiveness of mu-opioid receptor knockout mice to lipopolysaccharide-induced fever.
Recently, we demonstrated that lipopolysaccharide (LPS)-induced fever could be suppressed by a selective mu-opioid receptor antagonist, indicating that the mu-opioid system is involved in the LPS fever. In the present study, to confirm the role of the mu-opioid system in the pathogenesis of LPS fever, we used mice lacking the mu-opioid receptor. In the wild type (WT), following intraperitoneal (i.p.) injection of 100 microg kg(-1) of LPS, body temperature (T(b)) increased approximately 1 degrees C and remained elevated during the 360-min recording period. In the mu-opioid receptor knockout (MOR-KO) mice, the administration of 100 microg kg(-1) i.p. of LPS did not induce fever during the recording period. Saline by itself, given i.p., did not alter the T(b), either in WT or MOR-KO. These results confirm that the mu-opioid system is involved in LPS-induced fever.
Benamar
Khalid
K
Center for Substance Abuse Research, Temple University School of Medicine, 3400 N. Broad Street, Philadelphia, PA 19140, USA. kbenamar@temple.edu
McMenamin
Malgorzata
M
Geller
Ellen B
EB
Chung
Young G
YG
Pintar
John E
JE
Adler
Martin W
MW
D000818:Animals; D001831:Body Temperature / Q000187:drug effects / Q000235:genetics; D004361:Drug Tolerance / Q000235:genetics*; D005334:Fever / Q000139:chemically induced / Q000235:genetics* / Q000378:metabolism*; D008070:Lipopolysaccharides / Q000633:toxicity*; D051379:Mice; D008810:Mice, Inbred C57BL; D018345:Mice, Knockout; D017450:Receptors, Opioid, mu / Q000172:deficiency* / Q000235:genetics* / Q000502:physiology
D008070:Lipopolysaccharides; D017450:Receptors, Opioid, mu