Effects of prostaglandins on cerebral blood vessels: interaction with vasoactive amines

Prostaglandins B1 and B2 were topically applied to the pial vessels of mice and arteriolar constriction was observed. This constriction could be significantly increased if serotonin was added to B1, but not when norepinephrine was added. Response to B2 was not enhanced by the simultaneous addition of either serotonin or norepinephrine. Earlier work with prostaglandin F2alpha was replicated. F2alpha constricted pial arterioles and a significantly greater constriction was produced when norepinephrine was applied simultaneously with F2alpha. The data suggest that among the causes of cerebral vasospasm one should consider not only the action of singly agents, but also the combined effects of several agents that might be in contact with cerebral vessels.