Release of Proteolytic Enzyme from Cat Brain During Stimulation

Introduction  Reversible chemical changes in rapidly frozen homogenate have been described by other investigators which indicate that stimulation of the brain, either directly or indirectly through afferent nerves, induces a state of excitation in which the rate of protein breakdown increases, proteolytic enzymes are activated, and partial protein denaturation occurs; with intense and prolonged stimulation the denaturation may be irreversible.^1-3 The observation that certain proteolytic enzymes when incubated with plasma globulin form polypeptides^4,5 that can be assayed readily in minute amounts, offers a method for observing small increases of proteolytic enzymes in dilute solutions such as perfusate collected before and during excitation. A vasodilator polypeptide formed by the action of a proteolytic enzyme on plasma globulin has been shown to be an important mediator of local vasomotor control in the salivary gland.⁶ Also, human cerebrospinal fluid collected from patients with disorders of the central nervous system forms