title: Daily variation in an intensity of kaolin-induced writhing reaction in mice.
abstract: The daily variation in an intensity of kaolin-induced writhing reaction was examined in mice kept under conditions of light; 07:00 - 19:00 and dark; 19:00 - 07:00. The number of writhes was counted for 30 minutes after a single intraperitoneal injection of kaolin at 00:00, 02:00, 04:00, 06:00, 08:00, 10:00, 12:00, 14:00, 16:00, 18:00, 20:00 and 22:00. The number of writhes showed a daily variation with a peak at 18:00 and a trough at 06:00. The intensity of writhing reaction was significantly reduced by pretreatment with the bradykinin B1 (Des-Arg9-[Leu8]-BK) and B2 (icatibant) receptor antagonists. Significant daily variation in this parameter was still observed in the group with the B1 antagonist, but disappeared in the B2 antagonist-treated group. These results suggest that the kaolin-induced writhing reaction shows the daily variation with a peak at the end of the resting period and a trough at the end of the active period. The B2 receptor mediated stimuli appears to be involved in this phenomenon.
authors.affiliation: Department of Clinical Pharmacology, Jichi Medical School, Tochigi, Japan.
authors.forename: K
authors.initials: K
authors.lastname: Sakamoto
authors.forename: M
authors.initials: M
authors.lastname: Arakawa
authors.forename: M
authors.initials: M
authors.lastname: Ohmori
authors.forename: K
authors.initials: K
authors.lastname: Sugimoto
authors.forename: A
authors.initials: A
authors.lastname: Fujimura
mesh_terms: D000698:Analgesia; D000818:Animals; D001920:Bradykinin / Q000031:analogs & derivatives / Q000627:therapeutic use; D065168:Bradykinin Receptor Antagonists; D002940:Circadian Rhythm; D007616:Kaolin; D007700:Kinetics; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D010146:Pain / Q000139:chemically induced* / Q000188:drug therapy; D017440:Photoperiod
chemical_list: D065168:Bradykinin Receptor Antagonists; D007616:Kaolin; C051090:bradykinin, Leu(8)-des-Arg(9)-; C065679:icatibant; D001920:Bradykinin