title: Cold water swim stress inhibits the nociceptive responses to intrathecally administered somatostatin, but not substance P.
abstract: The effects of cold water swim stress (CWSS) on the nociceptive responses to i.t. administered substance P (SP) and somatostatin (SST) were examined. Male ICR mice, weighing about 30 g, were forced to swim in water at 20 degrees C for 3 min. In unstressed mice, i.t. injection of SP (0.1 nmol) and SST (1 nmol), respectively, produced nociceptive-related behaviors. Although CWSS had no effect on the intensity of the SP-induced nociceptive responses, CWSS significantly reduced the intensity of the SST-induced nociceptive responses. The effect of CWSS on the SST-induced nociceptive responses was blocked by naloxone (5 mg/kg, s.c.) and naltrindole (1 mg/kg, s.c.), a selective delta-opioid receptor antagonist, but not by beta-funaltrexamine (20 mg/kg, s.c.), a selective mu-opioid receptor antagonist. These results indicate that CWSS may selectively reduce the SST-induced nociceptive responses primarily through delta-opioid receptors.
authors.affiliation: Department of Pharmacology, Faculty of Pharmaceutical Sciences, Hoshi University, Tokyo, Japan.
authors.forename: J
authors.initials: J
authors.lastname: Kamei
authors.forename: H
authors.initials: H
authors.lastname: Hitosugi
authors.forename: M
authors.initials: M
authors.lastname: Misawa
authors.forename: H
authors.initials: H
authors.lastname: Nagase
authors.forename: Y
authors.initials: Y
authors.lastname: Kasuya
mesh_terms: D000818:Animals; D003080:Cold Temperature; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009270:Naloxone / Q000494:pharmacology; D010146:Pain / Q000503:physiopathology*; D017465:Receptors, Opioid, delta / Q000502:physiology; D013004:Somatostatin / Q000008:administration & dosage*; D013312:Stress, Physiological / Q000503:physiopathology*; D013373:Substance P / Q000008:administration & dosage*; D013550:Swimming
chemical_list: D017465:Receptors, Opioid, delta; D013373:Substance P; D009270:Naloxone; D013004:Somatostatin