Journal of neuroscience research
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Our recent morphologic studies indicated that peripheral nervous system (PNS) adrenergic neurons synthesize, transport, and store the serene protease, tissue plasminogen activator (t-PA) in axon terminals, many of which innervate vessel walls. Sympathoadrenal stimulation induces a surge of t-PA from vessel walls into the blood. The vascular endothelium, which constitutively secretes t-PA into blood also has long been widely assumed to be the principal source of this stress-induced release, but has not been verified as such. ⋯ Adventitial and endothelial ablations from normal large vessel explants produced greater reductions than small vessel endothelial ablations. Ganglion electrical stimulation also induced an acute microvascular release in vivo. These and past morphologic findings indicate a physiological infusion of t-PA into the vessel walls, blood, and other innervated matrices by sympathetic neurons.