Question

1-1. Ecstasy or MDMA uses a unique mechanism; it binds to the serotonin reuptake transporter and does two things. Ecstasy stops serotonin reuptake and causes the transporter to reverse direction, moving serotonin from the synaptic terminal into the synapse. Due to this mechanism, what effect will ecstasy have on postsynaptic neurons? (Include in your answer whether EPSP or IPSP is affected.)

1-2. The pharmaceutical company is looking to introduce a new drug that enhances neurotransmission. Knowing what you know about the physiology of neurotransmission, the company is asking you what part of the pathway you would recommend targeting and how that would enhance neurotransmission. Explain how your drug would work and what part of neurotransmission your drug would target.

Answer 1

1-1. Serotonin is a monoaminase neurotransmitter released by the raphe nucleus in brainstem.
Serotonin is associated with increased mental arousal and alertness.
When the reuptake of serotonin is inhibited and serotonin is moved to synapse, more amount of serotonin is available for binding to postsynaptic receptors. This results in increased excitatory post synaptic potential which causes mood elecation and feeling of ecstacy.
1-2. There are number of pathways through which neurotransmission can be increased. Increased release of neurotransmitter from presynaptic vesicles, increase in number of receptors at postsynaptic neurons, inhibiting reuptake of neurotransmitter and inhibiting degradation of the neurotransmitter are some of the mechanism through which increased neurotransmission can be achieved.
I will suggest the pathway of dopamine. Introducing a drug that mimincs the action of dopamine will bind to dopamine receptor at postsynaptic neurons. This will Increase intracellular levels of cAMP
by activating adenylate cyclase.This will cause increase in opening of sodium channels and increased neutransmission.