zapped

1) v.t. Neuroadapted. One is "zapped" when he is depressed on account of being elated at an earlier time. Explanation: There is an idea in neurochemistry that the proliferation of pleasure causing neurotransmitters (i.e. dopamine) will actually decrease one's sensitivity to those neurotransmitters (because organisms tend to maintain homeostasis. There various physiological mechanisms. The presence of dopamine, for instance, probably downregulates the dopamine receptor in the post-synaptic neuron, upregulates the enzymes that break down dopamine in the synapse, and upregulates the mechanisms that re-uptake dopamine in the pre-synaptic neuron. Supposedly, individuals suffering from bipolar disorder tend to overshoot resting levels of neurotransmitters, altrenating between manic and depressed phases.