Background.  Various psychological stresses induce degranulation of mast cells. It has been confirmed by animal experiments that stress induced by restraint promotes mast-cell degranulation in various organs, and that the degranulation is inhibited by pretreatment with corticotropin-releasing factor (CRF)-neutralizing antibodies, CRF receptor antagonists, and neurotensin (NT) antagonists. Previous studies have suggested that anxiety and fear induced in animals by psychological stressors promote the production and release of various neuropeptides and neurotransmitters, and induce degranulation of mast cells in several organs.

Aim.  To evaluate the effect of prior treatment with antipsychotic and anxiolytic agents to inhibit foot-shock (FS) stress-induced degranulation of mouse dermal mast cells.

Methods.  Using a communication box system, FS was administered to mice and the degranulated dermal mast cells were counted. Chlorpromazine (2 or 4 mg/kg body weight), tandospirone (10 mg/kg body weight) or CRA1000, a selective non-peptidic CRF receptor type 1 antagonist (10 or 100 mg/kg body weight) was injected intraperitoneally 1 h before exposure to FS.

Results.  After FS was administered, the number of dermal mast cells did not change. However, FS significantly increased the proportion of degranulated mast cells. Pretreatment of mice with chlorpromazine hydrochloride, an antipsychotic agent (2 or 4 mg/kg), or the anxiolytic agents tandospirone citrate (10 mg/kg) or CRA1000 (10 or 100 mg/kg), significantly inhibited the FS-induced mast-cell degranulation (P < 0.05, P < 0.01, P < 0.05, P < 0.05, and P < 0.05, respectively).

Conclusions.  Antipsychotic and anxiolytic agents may be effective treatments for stress-aggravated inflammatory skin diseases by inhibition of mast-cell degranulation.