T. Ichiyama et al., Inhibition of peripheral NF-kappa B activation by central action of alpha-melanocyte-stimulating hormone, J NEUROIMM, 99(2), 1999, pp. 211-217
With the rise in the field of neuroimmunomodulation research, there is incr
eased recognition of the influence of the nervous system and neuropeptides
in peripheral disease. The neuropeptide alpha-melanocyte-stimulating hormon
e (alpha-MSH) is a neuroimmunomodulatory agent that modulates production of
proinflammatory cytokines and inhibits peripheral inflammation via actions
on CNS receptors. We examined whether central alpha-MSH operates by inhibi
ting activation of the nuclear factor kappa B (NF-kappa B) that is essentia
l to the expression of proinflammatory cytokines and development of inflamm
ation in the periphery. Electrophoretic mobility shift assays of nuclear ex
tracts from the murine foot pad injected with TNF-alpha demonstrated that c
entrally administered alpha-MSH does inhibit NF-kappa B activation. Western
blot analysis revealed that this inhibition was linked to central alpha-MS
H-induced preservation of expression of I kappa B alpha protein in the peri
pheral tissue. The NF-kappa B and I kappa B alpha effects were inhibited in
mice with spinal cord transection. Intraperitoneal (ip) injection of the n
onspecific beta-adrenergic receptor blocker propranolol, and of a specific
beta(2)-adrenergic receptor antagonist, likewise prevented these effects of
central alpha-MSH; blockade of cholinergic, alpha-adrenergic, or beta(1)-a
drenergic receptors did not. Centrally administered alpha-MSH inhibited per
ipheral NF-kappa B activation and I kappa B alpha degradation even in mice
with nonfunctional melanocortin 1 receptors (MC1R). These findings indicate
that alpha-MSH can act centrally to inhibit NF-kappa B activation in perip
heral acute inflammation via a descending neural pathway. The pathway invol
ves beta(2)-adrenergic receptors, but does not require activation of MC1R w
ithin the brain. (C) 1999 Elsevier Science B.V. All rights reserved.