Question

Which of the following statements is true about cocaine?

O It activates dopamine receptors on a postsynaptic neuron and so acts as a direct dopamine agonist.
O It blocks potassium channels, keeping the presynaptic neuron in a state of depolarization and causing increased dopamine release, acting as a direct dopamine agonist.
O It blocks dopamine receptors on a postsynaptic neuron and so acts as an indirect dopamine agonist
O It is a GABA agonist, causing the inhibition of neurons that normally inhibit dopamine cells.
O It blocks dopamine transporters, preventing reuptake in the presynaptic neuron, and so acts as an indirect dopamine agonist.

Answer 1

Cocaine acts as an indirect dopamine agonist by blocking the reuptake of dopamine, increasing its availability in the synaptic cleft and causing a pleasurable 'high'.

Step-by-step explanation:

The statement that is true about cocaine is: It blocks dopamine transporters, preventing reuptake in the presynaptic neuron, and so acts as an indirect dopamine agonist. Cocaine enhances dopamine levels in the synaptic cleft by blocking the reuptake of dopamine into the presynaptic neuron.

This causes an accumulation of dopamine in the synapse, which results in prolonged stimulation of the post-synaptic dopamine receptors and is associated with the pleasurable 'high' experienced by users. It is the enhancement of dopamine action that is responsible for both the drug's stimulating effects and its potential for addiction.