It seems that all your classes have tests and papers due on the same day. You don’t know how you’re going to get everything done before it’s time to leave for spring break. You tell your friend Sam, and he tells you to speak to his "friend" Mike. Sam declares that "Mike just might have something that will help you out."
You agree, although you aren’t really sure what Sam is referring to. You meet up with Sam’s "friend," and he seems to be bouncing off the walls, talking a mile a minute. He says he can offer you some stuff that will increase your alertness, help you pull a few all-nighters, and even put you in a much better mood. He drops some white powder onto a mirror and divides it into little lines and asks if you would like a sample.
What drug is Mike abusing and offering you?
Answer the following questions:
1. Determine what drug the individual in your case has been using and what led you to believe this.
2. Determine what the subjective effects of the drug are (i.e., what has a person reported feeling after using the drug).
3. Determine what receptors, transporters, or neurotransmitters could be involved and how the drug affects these receptors, transporters, or neurotransmitters.

C) Cocaine acts by blocking the reuptake of certain neurotransmitters such as dopamine, norepinephrine, and serotonin. By binding to the transporters that normally remove the excess of these neurotransmitters from the synaptic gap, cocaine prevents them from being reabsorbed by the neurons that released them and thus increases their concentration in the synapses. Due to this, the natural effect of dopamine on the post-synaptic neurons is amplified. The group of neurons thus modified produces much more dependency (from dopamine), feelings of confidence (from serotonin), and energy (from norepinephrine) typically experienced by people who take cocaine.

In addition, because the norepinephrine neurons in the locus coeruleus project their axons into all the main structures of the forebrain, the powerful overall effect of cocaine can be readily understood.

In chronic cocaine consumers, the brain comes to rely on this exogenous drug to maintain the high degree of pleasure associated with the artificially elevated levels of some neurotransmitters in its reward circuits. The postsynaptic membrane can even adapt so much to these high dopamine levels that it actually manufactures new receptors. The resulting increased sensitivity produces depression and cravings if cocaine consumption ceases and dopamine levels return to normal.

Dependency on cocaine is thus closely related to its effect on the neurons of the reward circuit.