Production of 15-HETE by cultured smooth muscle cells from cerebral artery

Hydroperoxyeicosatetraenoic acids (HPETEs) are potent vasoconstrictors which have been implicated in the pathogenesis of the delayed cerebrovascular spasm which follows subarachnoid haemorrhage. We have previously shown that one of their stable breakdown products, 15-hydroxyeicosatetraenoic acid (15-HETE), is the major lipoxygenase product released from isolated cerebral arteries. To investigate the vascular cell type responsible for their production we have established the culture of smooth muscle cells from cerebral arteries and have measured their release of HETEs upon stimulation with arachidonic acid. The cultured cells isolated from bovine cerebral arteries expressed smooth muscle phenotype as they stained positively for smooth muscle alpha-actin and not factor VIII-related antigen. Furthermore, these cells possessed the calcium and potassium conductances characteristic of smooth muscle cells. Upon incubation with arachidonic acid, the major lipoxygenase product was 15-HETE; no leukotrienes were detected. The formation of 15-HETE was concentration-dependent and was attenuated by nordihydroguaiaretic acid, but not by indomethacin. Similar to intact cerebral artery, cultured cerebrovascular smooth muscle cells have lipoxygenase activity, the major product of which is 15-HETE. These results are consistent with a possible role of the HPETEs in the pathogenesis of cerebral vasospasm.