Prostaglandins and experimental cerebral vasospasm

Of the prostaglandins given alone in the cerebrospinal fluid, PGF(2α) caused spasm in ten of ten dogs, and PGF(1α) (also a pressor agent given intravenously) induced spasm in eight of ten dogs. PGE₂ also induced spasm in seven of eight animals. Reducing the dosage of the latter to 5μg/kg similarly produced spasm in three of four animals. Spasm was evident within 15 min and usually lasted at least 2 hr. The results with PGE₂ were unexpected since this agent is a depressor when given intravenously to dogs. In contrast to these compounds, PGE₁ failed to produce spasm in five animals. The effect of giving PGF(2α) with blood indicates that this prostaglandin will enhance the spasmogenic properties of the latter. These results clearly demonstrate that substances present in brain tissue and the CSF can induce cerebrovascular spasm.