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		6. Neurotransmitter removal It is important that the actions of neurotransmitters be rapid and transient. Neurotransmitters must be rapidly cleared out of the synapses. There are several mechanisms that aid in their removal; neurotransmitters can be
			a. Destroyed by specific enzymes b. Rapidly diffuse away c. Taken up via active transport
		Q. What would be the effect of persistence of neurotransmitters in the synapse? -prolonged stimulation, enhance activity 7. Effect of drugs Most drugs that act on the nervous system alter some aspect of synaptic function: - increase leakage of NT out of vesicle - block NT release - increase NT release - inhibit NT synthesis - block NT reuptake - block degrading enzymes - bind to receptor and block NT action (antagonist) ** - bind to receptor and mimic NT activity (agonist) ** - inhibit second messenger activity - enhance second messenger activity 8. Formation of synapses Synapses involve a high local concentration of the appropriate receptors. A given neuron has discrete patches of receptors so that it can receive both stimulatory and inhibitory inputs. Each type of receptor is localized by associating with unique proteins that connect it to the cytoskeleton. The clustering of the patch of receptors is triggered by contact with the axon tip. B. Neurotransmitters Table 48.1 You are not required to memorize this table; you are only responsible for neurotransmitters discussed in class. Remember, neurotransmitters are differentiated from hormones primarily by the way they are delivered.