Cocaine

• Cocaine is an illegal and addictive drug. It is taken recreationally for its stimulating effects; it speeds up the body e.g. heart rate. Cocaine is very fast acting and has immediate effects on neural transmission within the brain. Users experience a 'come down' after taking it due to depleted levels of dopamine and the bodies need to recover.
• Cocaine works on the reward pathway and dopamine receptors in the brain.
• Cocaine draws on the idea that there is reuptake by the presynaptic neuron of neurotransmitter left in the synaptic gap.
• Cocaine blocks the binding site on the reuptake receptor, or transporter molecule, and stops the reuptake of dopamine back into the presynaptic neuron
• This blocking of reuptake means there is excess dopamine in the synapse because it is not being reabsorbed.
• This excess of dopamine leads to over-stimulation at the postsynaptic receptors.

  Therefore there is more dopamine than usual creating intense feelings of pleasure, or euphoria.
• long term effects of cocaine ;The continuous binding of dopamine to the dopamine receptors is overstimulating and negatively affects the neural transmission, Overtime the dopamine receptors become damaged, changing shape which prevents neurotransmitters binding successfully, The number of dopamine receptor sites will also decrease, This leads to desensitisation and more dopamine is required to stimulate the post synaptic neuron to a 'normal level', As there is a loss of response to the drug so more is needed to experience the same effect, this is called tolerance.
• A person becomes addicted because they crave the intense pleasure experienced, due to activation of the dopamine reward pathway, and therefore want to take the drug again because it is rewarding.
• Typically dopamine increases in response to narural rewards such as food when cocaine in taken dopamine increases are exaggerated and communication is altered