[Effect of cysteamine on vocalization responses by arterial algogenics in guinea pigs].
Effects of cysteamine (2-mercaptoethylamine) on vocalization responses, a parameter of nociceptive response, was studied in conscious guinea pigs. Intra-arterial injection of bradykinin (3 micrograms), acetylcholine (300 micrograms), capsaicin (3 micrograms) and vanillyl n-nonoylamide (3 micrograms, VNA) induced severe vocalization responses. Three hours after an administration of cysteamine (300 mg/kg, s.c.), a significant suppressive effect was observed for bradykinin and acetylcholine-evoked vocalization. A weak suppressive effect appeared in capsaicin and VNA-evoked vocalization, but there were not statistically significant changes on vocalization counts when compared with the value of the saline-treated animals. However, consecutive pretreatment of guinea pigs with VNA led to a complete suppression of capsaicinoids-evoked vocalization only. Cysteamine completely suppressed bradykinin, acetylcholine, capsaicin and VNA-evoked vocalization responses in VNA desensitized guinea pigs. These findings suggest that the mechanisms of bradykinin and acetylcholine-evoked vocalization response differ from that of capsaicinoids.
Ando
R
R
Center for Laboratory Animal Science, Tohoku College of Pharmacy, Sendai, Japan.
Yonezawa
A
A
Kawamura
S
S
Fujii
T
T
Sakurada
S
S
Kisara
K
K
D000109:Acetylcholine / Q000008:administration & dosage / Q000494:pharmacology; D000818:Animals; D001920:Bradykinin / Q000008:administration & dosage / Q000494:pharmacology; D002211:Capsaicin / Q000008:administration & dosage / Q000494:pharmacology; D003543:Cysteamine / Q000494:pharmacology*; D006168:Guinea Pigs; D007269:Injections, Intra-Arterial; D007271:Injections, Intradermal; D008297:Male; D009619:Nociceptors / Q000187:drug effects*; D014641:Vanillic Acid / Q000008:administration & dosage / Q000031:analogs & derivatives / Q000494:pharmacology; D014828:Vocalization, Animal / Q000187:drug effects*
C005871:vanillyl-N-nonylamide; D003543:Cysteamine; D014641:Vanillic Acid; D000109:Acetylcholine; D002211:Capsaicin; D001920:Bradykinin