Recreational drugs and the CNS - biological

Describe the first aspect of recreational drugs of the transgression process in the CNS (AO1)

A drug is a chemical you take that impacts the way your body works. They can change the message your brain cells are sending to each other and the rest of the body by interfering with your brain’s chemical signals.

All recreational drugs increase dopamine levels. 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 leading to over-stimulation at the postsynaptic receptors. Therefore there is more dopamine than usual creating intense feelings of pleasure, or euphoria. Continuous use can damage dopamine receptors which leads to desensitisation and addiction.

What are the strengths and weaknesses of the first aspect of recreational drugs of the transgression process in the CNS (AO3)

Supporting AO3:

- Weinshenker and Schroeder conducted a study on mice’s brains

- They found that cocaine’s impact is due to the level of activity of dopamine in the brains reward system

- This supports the idea that cocaine’s influence is impacted by dopamine levels

Weakness AO3:

- The studies studies were conducted on animals which means the results can’t necessarily be generalised to humans as the human brain involves various interactions between neurotransmitters so we cannot draw a cause-and-effect conclusion

Describe the second aspect of recreational drugs of the transgression process in the CNS (AO1)

Heroin is usually injected intravenously and flows through the bloodstream to the brain.

Once in the brain is it broken down into morphine (a closely related opioid) which binds to specific opioid receptors at the synapse - (mu) receptors in the cerebral cortex, limbic system and hypothalamus. Receptors for heroin/morphine exist in the body because the CNS has its own opioid system.

Endorphins and enkephalins are the bodies natural painkillers. Heroin takes advantage of this system by binding with the natural opioid receptors to enhance its effects. Heroin is an agonist drug because it mimics the action of another chemical, i.e. it binds to the natural opioid receptors because it has a complimentary shape

What are the strengths and weaknesses of the second aspect of recreational drugs of the transgression process in the CNS (AO3)

AO3 supporting:

- Morgan et al 2013

AO3 refuting:

drug replacement therapy only tackles the neurobiology of drug addiction and not the psychological willingness of the person

- Therefore the treatment may not be successful because of the unpleasant withdrawal symptoms and cravings