Cluster headache: increased incorporation of (1-14C)arachidonic acid into phosphatidylserine in polymorphonuclear cells

Vasoactive metabolites deriving from arachidonic acid (AA) have been considered as putative mediators in the pathogenesis of various types of headache. In the present study we therefore compare the ability to synthesize AA containing precursor phospholipids in polymorphonuclear cells (PMNs) from healthy controls and cluster headache patients. 3.7% ± 1.4 (mean ± SD) of the (1-¹⁴C)AA incorporated into total PMN glycerophospholipids (GPLs) was recovered in the phosphatidylserine (PS) in a group of cluster headache patients ( n = 12). This was almost twice the value of 1.9% ± 0.8% found in a corresponding group of 24 healthy controls ( p < 0.001). A significant decrease in the incorporation of (1-¹⁴C)AA into phosphatidylcholine (PC) ( p < 0.01) and an increase in the incorporation of (1-¹⁴C)AA into phosphatidyletanolamine (PE) ( p < 0.05) were also found in cluster headache patients when compared to the control group. The increased incorporation of (1-¹⁴C)AA into PS in PMNs from this group of patients is interesting because PS plays an important role in the activation of protein kinase C, an enzyme involved in transmembrane signalling. The clinical implications of the present findings in cluster headache, if any, cannot yet be defined.