Biology Reference
In-Depth Information
Antigens
IgE
IgG
Mast cell
Neurite
CNS
Axon
reflex
Mast
cell
Nerve cell
body
Tissue
targets
Figure 7.1 Neurogenic inflammation.
A schema outlining our concept that mast cells
may behave as sensory receptors for antigens. As a result of passive sensitization by specific
antibodies (IgE or IgG), upon subsequent interactions with an antigen, mast cells will release
mediators that may affect nerves in the local environment. Information may pass back to the
nerve cell body, or affect, by axon reflex, local tissue targets. Through interneuronal contacts,
information would be expected to go to the spinal cord and/or to the central nervous system.
Alternatively, the CNS might act by an efferent system to modulate mast cell function.
Source: From Bienenstock, J.
are able to induce mast-cell discharge, and therefore they are pro-inflammatory. In
contrast, somatostatin and galanin are anti-inflammatory mediators
[24]
. These medi-
ators enable sensory nerves to induce and also to inhibit inflammation. The CNS
ensures that the correct amount and type of mediators are released into the target
area where a pathological process is to be controlled.
7.5 Some Functions of the Sensory Nerve
Mast Cell Pathway
There is evidence to suggest that the sensory nerve mast cell (SNMC) pathway reg-
ulates blood flow and participates in gastrointestinal physiology
[67,68]
. Sensory
nerves may induce or down-regulate inflammation by regulating the discharge of mast
cells. Under normal conditions, inflammation is the ultimate phase of host defense
reactions exerted by the CNS, NATIM, and ADIM systems. By strict regulation of
the inflammatory process, the CNS ensures that this potentially harmful reaction will
provide protection for the host while staying within limits compatible with survival.
Maladjustment of the SNMC regulatory pathway has the following pathological
consequences.
7.5.1 SNMC Malfunction Causes Diseases
The current dogma is that allergy is due to excess IgE antibodies, which discharge mast
cells after contact with minute amounts of antigen (allergen) and create a powerful
