Stimulation of phosphoinositide hydrolysis via class I antigen-specific recognition in murine cardiac tissue

Induction of polyphosphoinositide hydrolysis in cardiac tissue by specific recognition of class I histocompatibility antigens was assayed. C3H (H-2 k) mice auricles were labelled with myo- 3H]inositol precursor and inositol phosphate production in the presence or absence of anti-class I k products was measured. Anti-class I, but not anti-class II products specifically increased phosphoinositide turnover. This increment was partially blocked by muscarinic cholinergic and α-adrenergic blockers and even more so by the phospholipase C inhibitor NCDC. Alloantibodies specifically directed against class I antigens could then exert stimulation of phospholipase C-mediated phosphoinositide hydrolysis through the interaction with muscarinic cholinergic and/or α-adrenergic receptors. The induction of intracellular second messengers by class I antigens and hormone-receptor interactions is discussed.