Effect of phospholipase C blockade on cerebral vasospasm.

BACKGROUND

Delayed cerebral ischemia due to cerebral vasospasm remains a major cause of morbidity and mortality following subarachnoid hemorrhage. Oxyhemoglobin (OxyHb) and vasoconstrictor prostanoids have been suggested as putative spasmogens. We have previously reported a synergistic vasoconstrictive action between thromboxane A(2) (TXA(2)) and OxyHb. In the present study we examine the effect of neomycin, a phospholipase C inhibitor, on the cerebral vasoconstriction induced by TXA(2) and OxyHb.

METHODS

Using an in vitro tissue bath method, we assess the effect of neomycin in a concentration-dependent manner, on isolated porcine basilar arteries constricted by U-46619 (TXA(2) analogue) and OxyHb.

RESULTS

The functional synergism between TXA(2) and OxyHb, leading to significant cerebral vasoconstriction, is attenuated in a dose-dependent manner by neomycin.

CONCLUSION

Blockade of phospholipase C may provide an alternative strategy in the treatment of subarachnoid-hemorrhage-induced cerebral vasospasm.