Stimulation of inositol phosphate production by propranolol in human neutrophils.

1. Propranolol has been reported to be beneficial in treating patients suffering from a variety of diseases including migraine, psychosis and schizophrenia. The mode of action of propranolol in the treatment of the above diseases is not clear. 2. An investigation into the possible effect of propranolol on receptor activated inositol phospholipid hydrolysis was carried out using human neutrophils. Receptor activated inositol phosphate production by formyl-methionyl-leucyl-phenylalanine has also been studied. 3. DL-propranolol caused a time and concentration dependent increase in inositol phosphate generation which was similar to that obtained for chemotactic peptide in neutrophils. The EC50 for propranolol was 2 microM compared to 0.5 microM for chemotactic peptide. 4. These results indicate the possibility that propranolol has a direct action on inositol phospholipid hydrolysis in addition to its beta-blocking effect.