Studies of Proteolytic Enzymes in Cerebrospinal Fluid

Abstract

A study of tissue fluid removed from regions of local tenderness in the scalp during vascular headache of the migraine type indicated that this fluid contained a painthreshold-lowering substance.^4,15It had many of the properties of vasodilator polypeptides derived from plasma proteins. Armstrong et al.^2,3demonstrated that such polypeptides were present in blister fluid, in fluid collected from painful joints, and in inflammatory pleural fluid. At about the same time, Hilton and Lewis¹¹described a proteolytic enzyme present in saliva and in saline perfusate of the salivary gland. This enzyme formed vasodilator polypeptides when incubated with plasma proteins. Increased amounts of enzyme were observed during heightened metabolic activity of the gland. Hilton and Lewis concluded that the enzyme and polypeptide are responsible for local vasomotor control in the salivary gland. The properties of the polypeptide correspond closely to those of "bradykinin," the name given by Rocha e