Brain mast cells act as an immune gate to the hypothalamic-pituitary-adrenal axis in dogs.

Abstract

Mast cells perform a significant role in the host defense against parasitic and some bacterial infections. Here we show that in the dog, degranulation of brain mast cells evokes hypothalamic-pituitary-adrenal responses via histamine release. A large number of mast cells were found in a circumscribed ventral region of the hypothalamus, including the pars tuberalis and median eminence. When these intracranial mast cells were passively sensitized with immunoglobulin E via either the intracerebroventricular or intravenous route, there was a marked increase in the adrenal cortisol secretion elicited by a subsequent antigenic challenge (whether this was delivered via the central or peripheral route). Comp.48/80, a mast cell secretagogue, also increased cortisol secretion when administered intracerebroventricularly. Pretreatment (intracerebroventricularly) with anti-corticotropin--releasing factor antibodies or a histamine H(1) blocker, but not an H(2) blocker, attenuated the evoked increases in cortisol. These data show that in the dog, degranulation of brain mast cells evokes hypothalamic-pituitary-adrenal responses via centrally released histamine and corticotrophin-releasing factor. On the basis of these data, we suggest that intracranial mast cells may act as an allergen sensor, and that the activated adrenocortical response may represent a life-saving host defense reaction to a type I allergy.

• Authors: I Matsumoto, Y Inoue, T Shimada, T Aikawa
• Journal: The Journal of experimental medicine (J Exp Med) Vol. 194 Issue 1 Pg. 71-8 (Jul 02 2001) ISSN: 0022-1007 [Print] United States
• PMID: 11435473 (Publication Type: Journal Article)

Chemical References

• Antibodies, Monoclonal
• Histamine H1 Antagonists
• Histamine H2 Antagonists
• Immunoglobulin E
• Histamine
• Corticotropin-Releasing Hormone
• Hydrocortisone

Topics

• Animals
• Antibodies, Monoclonal (pharmacology)
• Brain (cytology)
• Corticotropin-Releasing Hormone (immunology)
• Dogs
• Female
• Histamine (metabolism)
• Histamine H1 Antagonists (pharmacology)
• Histamine H2 Antagonists (pharmacology)
• Hydrocortisone (metabolism)
• Hypersensitivity (immunology)
• Hypothalamo-Hypophyseal System (cytology, immunology)
• Immunoglobulin E (immunology)
• Male
• Mast Cells (drug effects, immunology)
• Pituitary-Adrenal System (immunology)