What happenes when the brain is exosed to too much norepinephrine?

Neurotransmitter: Norepinephrine (ne) is a sympathomimetic catecholamine that is synthesized in the adrenal medulla, in sympathetic neuron terminals, and in the brainstem and pons. Along with serotonin and dopamine, norepinephrine is a neurotransmitter in the brain. "too much" could lead to activation &anxiety. It may enhance some types of aggression in animals, plus impulsivity and episodic violence in humans.