Histamine secretion from mast cells stimulated with ATP

Area of Science:

• Immunology
• Pharmacology
• Cell Biology

Background:

• Mast cells are key immune cells involved in allergic responses.
• Adenosine triphosphate (ATP) is a ubiquitous signaling molecule.
• The role of ATP in mast cell degranulation is not fully understood.

Purpose of the Study:

• To investigate the effects of Adenosine triphosphate (ATP) on mast cell degranulation.
• To identify the purinergic receptors involved in ATP-mediated mast cell responses.
• To determine the species and tissue specificity of ATP-induced mast cell mediator release.

Main Methods:

• Primary rat serosal mast cells were isolated and stimulated with ATP.
• Calcium-dependent release of histamine and prostaglandin D2 was measured.
• The effects of various antagonists (Reactive Blue 2, Suramin) and agonists were assessed.
• Responses were compared across different species (rat, guinea pig, human) and tissues.

Main Results:

• ATP induced non-cytotoxic release of histamine and prostaglandin D2 from rat mast cells.
• The release was calcium-dependent and showed significant tissue and species specificity (unresponsive in guinea pig and human mast cells).
• Antiasthmatic chromones were ineffective, while flavonoids and cAMP-active drugs inhibited the release.
• Secretion was blocked by P2Y and P2X antagonists, but not by common P2 receptor agonists.

Conclusions:

• ATP acts via a novel purinoceptor or binding site on specific mast cell types.
• This purinoceptor differs from known P2X and P2Y receptors.
• The findings have implications for understanding mast cell activation and potential therapeutic targets.