[Effects of serial administration of vanillyl n-nonoylamide on vocalization responses by arterial algogenics in guinea pigs].

R Andoh, A Yonezawa, T Fujii, S Sakurada, T Sakurada, K Kisara

Index: Nippon. Yakurigaku Zasshi. 85(6) , 481-6, (1985)

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Abstract

Desensitizing effects of vanillyl n-nonoylamide, one of the synthetic capsaicinoids, were investigated by algogenics induced vocalization in conscious guinea pigs. Intra-arterial administration of bradykinin, acetylcholine and capsaicinoids (capsaicin, dihydrocapsaicin, vanillyl n-nonoylamide) evoked strong vocalization responses. Increasing doses (50 mg/kg, 100 mg/kg, 200 mg/kg, 400 mg/kg) of vanillyl n-nonoylamide were given to guinea pigs by subcutaneous administration for 4 days. Consecutive administration of vanillyl n-nonoylamide produced a weak but not significant desensitizing effect on bradykinin, acetylcholine-evoked vocalization at several doses. However, a complete suppressive effect on capsaicinoids-evoked response was observed in animals treated with serial administration of vanillyl n-nonoylamide. A weak vocalization response reappeared by three kinds of capsaicinoids (3 micrograms), but there were statistically significant effects on vocalization count when compared with the control values. It was therefore concluded that serial administration of vanillyl n-nonoylamide had a selective desensitizing action on chemonociceptors.