Differential roles of spinal cholera toxin- and pertussis toxin-sensitive G proteins in nociceptive responses caused by formalin, capsaicin, and substance P in mice.
The aim of the present study is to characterize the roles of spinal cholera toxin (CTX)- and pertussis toxin (PTX)-sensitive G proteins in the regulation of various nociceptive responses. The effects of intrathecal (i.t.) pretreatments with CTX and PTX on the formalin (subcutaneous)-, capsaicin (i.t.)-, and substance P (SP; i.t.)-induced nociceptive behaviours were examined in mice. Pretreatment with CTX (i.t.; 24 h before) significantly and dose-dependently (0.05-0.5 microg) suppressed both the first and second phases of the formalin-induced nociceptive behaviour. On the other hand, pretreatment with PTX (i.t., 6 days before) at the same doses (0.05-N0.5 microg) did not affect the formalin-induced response. Capsaicin (i.t., 0.5 microg)- and SP (i.t., 0.7 microg)-induced nociceptive behaviours were attenuated by the pretreatment with CTX. In addition, SP-induced nociceptive response was also attenuated by the pretreatment with PTX. However, the capsaicin-induced nociceptive response was not influenced by PTX pretreatment. These findings suggest that, at the spinal cord level, CTX-sensitive G-proteins are involved in the formalin-, capsaicin-, and SP-induced nociceptive behavioural responses, whereas PTX-sensitive G proteins are involved in SP-induced nociceptive response.
Chung
K M
KM
Department of Pharmacology and Institute of Natural Medicine, Hallym University, Kangwondo, South Korea.
Lee
K C
KC
Choi
S S
SS
Suh
H W
HW
D000818:Animals; D001522:Behavior, Animal / Q000187:drug effects / Q000502:physiology; D002211:Capsaicin / Q000494:pharmacology; D002772:Cholera Toxin / Q000494:pharmacology*; D004305:Dose-Response Relationship, Drug; D004347:Drug Interactions / Q000502:physiology; D005557:Formaldehyde / Q000494:pharmacology; D019204:GTP-Binding Proteins / Q000187:drug effects* / Q000378:metabolism; D007278:Injections, Spinal; D008297:Male; D051379:Mice; D008813:Mice, Inbred ICR; D009474:Neurons / Q000187:drug effects* / Q000378:metabolism; D009619:Nociceptors / Q000187:drug effects* / Q000378:metabolism; D010146:Pain / Q000139:chemically induced / Q000378:metabolism* / Q000503:physiopathology; D010147:Pain Measurement / Q000187:drug effects; D017288:Pain Threshold / Q000187:drug effects / Q000502:physiology; D037342:Pertussis Toxin; D013116:Spinal Cord / Q000187:drug effects* / Q000378:metabolism; D013373:Substance P / Q000494:pharmacology; D009435:Synaptic Transmission / Q000187:drug effects / Q000502:physiology; D010566:Virulence Factors, Bordetella / Q000494:pharmacology*
D010566:Virulence Factors, Bordetella; D005557:Formaldehyde; D013373:Substance P; D002772:Cholera Toxin; D037342:Pertussis Toxin; D019204:GTP-Binding Proteins; D002211:Capsaicin