Norepinephrine uptake into cerebral cortical synaptosomes after one fight or electroconvulsive shock.

Membrane affinity for the neurotransmitter norepinephrine is rapidly but reversibly decreased in nerve terminals of the cerebral cortex by intense nervous stimulation. This should adaptively facilitate alerting during acute emergency and stress. The Michaelis constant (K(m)) for the high-affinity active uptake of norepinephrine into crude synaptosome-rich homogenates of the cerebral cortices of mice was increased 68 percent after 15 minutes of intense fighting and 110 percent 5 minutes after a single electroconvulsive shock. These changes were no longer evident 18 to 20 hours later.