embrane. 5htp is synthesized from tryptophan, which is found in a diet high in proteins, however, tryptophan must go through a number of metabolic changes before it turns into 5htp (Sferios). After being synthesized, it is stored in pre-synaptic or membrane vesicles (Leon van Aertes, PhD). Serotonin’s main functions are to control mood, appetite, and sleep. There are other neurotransmitters in the brain that function along with serotonin. Serotonin and dopamine are the two that are closely related to accepted hypotheses about the neurotoxicity of MDMA. The normal function of serotonin in a neuron is much different from the actions that take place once MDMA is taken into the system. Normally, the molecules of serotonin remain in the axon terminal until an electrical signal from the brain tells the molecules to be released. Transport vesicles in the axon terminal take up the serotonin and then bond with the cell surface membrane and bud off into the synapse to release serotonin (Sferios). There are two specialized parts of the neurons that function in this serotonergic system. First, the receptors, at the ends of the dendrites, which have the specific function of absorbing the serotonin into the cell and beginning its transport, down the axon to the next terminal. When normal amounts of serotonin are released, the number of these receptors remains small, because serotonin is a neurotransmitter that takes a lot of time to be synthesized and, thus, not much is used at any given time. The second part of the system is the reuptake transporters on the membranes of the axon terminals. Usually, when serotonin is released into the synapse, there are not enough receptors to accept all the transport vesicles secreted. When this happens, some are accepted back into the axon terminal by these reuptake transporters, where they are stored for later use, or destroyed by certain enzymes called monoamine oxidase, to be discussed later....
