Immobilization increases norepinephrine release and reduces natural killer cytotoxicity in the conscious rat spleen. Nobuakieeshimizu, Yasuoeekaizuka, Tetsuroeehori, and Hideyukieenakane. Department of Chemistry & Chemical Engineering, Kanazawa University, Kanazawa 920, Japan, Department of Physiology, Faculty of Medicine, Kyushu University, Fukuoka 812, Japan
APStracts 3:0058R, 1996.
The purpose of this study was to investigate whether immobilization -stress would affect the cytotoxic activity of natural killer (NK) cells through the changes in norepinephrine release in the spleen. An in vivo microdialysis technique consisting of high-performance liquid chromatography with electrochemical detection was used to examine norepinephrine levels in the spleen of the conscious rat. The results of the physiological and pharmacological manipulations indicated that norepinephrine recovered in the dialysis solution was mainly derived from the nerve terminals of the splenic sympathetic nerve. Immobilization-stress rapidly increased norepinephrine levels to 817.4+/-181.7% of baseline in conjunction with the suppression of NK cytotoxicity. Both the increased levels of norepinephrine and the immunosuppression of NK cytotoxicity by immobilization-stress were significantly attenuated after surgical denervation of the splenic sympathetic nerve. The results suggest that immobilization-induced suppression of splenic NK cytotoxicity is mediated predominantly through enhanced activity of the splenic sympathetic nerve.

Received 29 July 1994; accepted in final form 3 February 1996.
APS Manuscript Number R414-4.
Article publication pending Am. J. Physiol. (Regulatory Integrative
Comp. Physiology).
ISSN 1080-4757 Copyright 1996 The American Physiological Society.
Published in APStracts on 13 March 96