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Substance P induces histamine release from human pulmonary mast cells
L G Heaney1, L J Cross, C F Stanford
1Department of Clinical Biochemistry, Queen's University of Belfast, UK.
Summary
Substance P stimulates histamine release from human mast cells in the airways, a process linked to asthma severity. This neuropeptide may activate mast cells, contributing to bronchoconstriction in asthma patients.
Area of Science:
- Immunology
- Respiratory Medicine
- Neuroscience
Background:
- Substance P is known to trigger histamine release from mast cells in skin and rodents.
- Neuropeptide-mediated reflexes are implicated in the pathophysiology of asthma.
Purpose of the Study:
- To investigate the effect of substance P on human mast cells obtained from bronchoalveolar lavage (BAL).
- To explore the role of substance P-induced mast cell activation in asthma.
Main Methods:
- Human mast cells were isolated from BAL samples of 35 patients.
- Histamine release was measured in response to substance P and calcium ionophore A23187.
- Substance P-induced release was assessed for energy dependence and correlation with mast cell counts.
Main Results:
- Both substance P and A23187 significantly increased histamine release compared to spontaneous release.
- Substance P-induced histamine release was energy-dependent and blocked by antimycin A.
- Mast cell counts correlated significantly with substance P-induced histamine release.
Conclusions:
- Substance P activates human mast cells from the airways, leading to histamine release.
- This activation mechanism, particularly in the context of increased mast cell numbers in asthma, may contribute to the bronchoconstrictor effects of substance P in vivo.