Relationships between mast cells and the nervous system

We and others have shown bi-directional mast cell communication with nerves both in vitro and in vivo. Many examples of this now exist in terms of skin, lung, intestine and urinary bladder both in vitro and in vivo. This communication appears to be important in a variety of situations relating to emotion, behaviour, stress and allergic and other hypersensitivity reactions, and these interactions appear to be important also in host resistance and responses to toxins. It is reasonable to conclude that mast cells and nerves can form a homeostatic unit, that mast cells are present in part to act as relays of environmental information to the nervous system, and that in turn they can be involved in the regulation of immune and inflammatory responses. They can act as a switchboard in this latter condition, or as a regulatory gateway in control of the release of hormones in the HPA axis, Mast cells are multifunctional cells and when associated with nerves, these functions are further amplified, and in this sense they can act both as conductors of the orchestra as well as players within it. (C) 2002 Editions scientifiques et medicales Elsevier SAS.