Autonomic Nervous SystemPotent suppressive effects of urocortin on splenic lymphocyte activity in ratsOkamoto, Shiki1; Ishikawa, Ikuyo1; Kimura, Kazuhiro1; Saito, Masayuki1,2Author Information 1Laboratory of Biochemistry, Department of Biomedical Sciences, School of Veterinary Medicine, Hokkaido University, Sapporo 060-0818, Japan 2Corresponding Author: Masayuki Saito ACKNOWLEDGEMENTS: This work was supported by a Grant-in-Aid for Scientific Research from the Ministry of Education, Science, and Culture of Japan, and also by a grant from the Naito Foundation, and a Sasakawa Scientific Research Grant from The Japan Science Society. Received 23 September 1998; accepted 5 October 1998 NeuroReport: December 21st, 1998 - Volume 9 - Issue 18 - p 4035-4039 Buy Abstract To assess the possible role of urocortin, a recently identified neuropeptide related to corticotropin-releasing factor (CRF), in modulation of peripheral immune functions, the effects of intracranially administrated urocortin on the proliferative activity of splenic lymphocytes were examined in rats. Intracerebroventricular (i.c.v.) injection of urocortin (1 ng) produced a marked decrease in the proliferative response of splenocytes to a mitogen. The suppressive effect of urocortin was abolished by pretreatment with a ganglionic blocking agent (chlorisondamine) or β-adrenergic receptor antagonist (propranolol), but not by adrenalectomy. These results suggest that urocortin is an important neuropeptide involved in the brain control of peripheral immune functions such as stress-induced immunosuppression, and that the suppressive effect of urocortin is mediated by the sympathetic nervous system. © 1998 Lippincott Williams & Wilkins, Inc.