T. Watanabe et al., ACTH RESPONSE INDUCED IN CAPSAICIN-DESENSITIZED RATS BY INTRAVENOUS-INJECTION OF INTERLEUKIN-1 OR PROSTAGLANDIN-E, Journal of physiology, 475(1), 1994, pp. 139-145
1. We investigated whether afferent nerves are involved in the develop
ment of adrenocorticotrophic hormone (ACTH) responses induced either b
y systemic administration of interleukin-1 beta (IL-1 beta) and prosta
glandin E(2), or by psychological stress. The capsaicin desensitizatio
n method was used to impair afferent C fibres and we compared the ACTH
responses between capsaicin desensitized and vehicle pretreated contr
ol rats. 2. The present results showed that the capsaicin desensitized
rats had significantly smaller increases in plasma ACTH than the cont
rol rats in response to intravenous injection of IL-1 beta or prostagl
andin E(2). 3. There were no significant differences between the capsa
icin desensitized and control rats in the ACTH responses induced by ca
ge switch stress. 4. The capsaicin desensitized rats responded to intr
avenous injection of corticotrophin releasing factor (CRF) with a grea
ter increase in the plasma level of ACTH than the control rats, indica
ting that capsaicin pretreatment resulted in augmentation of pituitary
gland sensitivity to CRF. 5. These results suggest that afferent neur
ons play an important role in the ACTH responses induced by systemic i
njection of IL-1 beta or prostaglandin E(2).