Many studies have demonstrated that ablation of the sympathetic nervous 
system (SNS) alters subsequent immune responses. Researchers have 
presumed that the altered immune responses are predominantly the result 
of the peripheral phenomenon of denervation. We, however, hypothesized 
that chemical sympathectomy will signal and activate the central nervous 
system (CNS). Activation of the CNS was determined by 
immunocytochemical visualization of Fos protein in brains from male 
C57BL/6 mice at 8, 24, and 48 h following denervation. A dramatic 
induction of Fos protein was found in the paraventricular nucleus (PVN) of 
the hypothalamus and other specific brain regions at 8 and 24 h compared 
to vehicle control mice. Dual-antigen labeling demonstrates that 
corticotrophin releasing factor (CRF)-containing neurons in the PVN are 
activated by chemical sympathectomy; however, neurons containing 
neurotransmitters which may modulate CRF neurons, such as vasopressin, 
tyrosine hydroxylase, and adrenocorticotropin, do not coexpress Fos. Our 
findings suggest an involvement of the CNS in sympathectomy-induced 
alterations of immunity. 
 
 
Central Nervous System Activation following Peripheral Chemical Sympathectomy: Implications for Neural–Immune Interactions
Brain, Behavior, and Immunity 
Volume 12, Issue 3, September 1998, Pages 230-241