recreational drugs & neurotransmitters

• what are recreational drugs (2)

  recreational drugs are drugs taken for enjoyment rather than medical reasons & they affect existing neurotransmitter in the CNS e.g: an example is stimulants which increase feelings of well being
• what are opioids

  opioids are painkillers producing a quick feeling of pleasure
• what are sedatives

  sedatives slow down normal brain function producing a drowsy or calming effect
• what are hallucinogens

  hallucinogens are drugs which cause altered perception and feeling such as seeing colours
• describe the effects and action mechanism that a drug has on the synapse (4)

  • cocaine
  • heroin
• describe cocaine

  cocaine is a stimulant drug which acts on the MP associated with the dopamine reward system in the brain called the nucleus accumbens
• mechanism of cocaine

  cocaine acts by mimicking the neurotransmitter to agonise (block) the receptors at the terminal buttons of the presynaptic neuron leading to dopamine molecules staying in the synapse
• effect of cocaine

  excess of dopamine causes a person to feel euphoric and overtime, dopamine receptors become downregulated due to damage of cocaine on receptors so fewer receptors active - decreases number of dopamine produced in the body so explains withdrawal effects and cravings for drug
• describe heroin

  heroin is an opioid drug which depresses CNS activity - acts on neurons with opioid receptors in the cerebral cortex, limbic system and hypothalamus
• mechanism of heroin

  • opioid receptors in the brain inform CC, LS and hypothalamus to release more endorphins
  • as heroin agonises opioid receptors for longer than normal neurotransmitters, opioid system produces excess levels of endorphins causing a person to feel pleasure
• effects

  over time, opioid receptors become downregulated so fewer receptors active - means quantity of opioid in the brain declines explaining withdrawal and craving of the drug and tolerance - as body makes less endorphins, these pains make the drug user crave drugs again
• strength of how drugs affect neurotransmission process

  • from animal research - cocaine works on dopamine reward system
  • weinshenker & schroeder (2007) deliberately damaged MP in mouse brains so mice were unable to create dopamine - mice used cocaine given in lab. once brain lesioning was done, no longer used cocaine - behaviour did not occur when other areas of mouses brain was destroyed
  • cocaines high inducing effects are due to dopamine and its reward system
• weakness (counterpoint)

  • research on recreational drugs and effects based on animal studies
  • dopamine does not only affect a single neurotransmitter (affects noadrenaline system) and humans have complex social and psychological issues that could be an explanation for usage of drugs
  • animal research lacks validity so cant be used for how drugs affect humans
• strength

  • knowing drugs effect on CNS = more treatments available treating addiction
  • knowledge that heroin binds to opiate receptor les to development of naloxone - antagonist drug (blocks) for opioid receptors to be used in addiction treatment and helped reduce withdrawal symptoms
  • knowledge helped develop real treatments
• how do recreational drugs change the way neurotransmitters operate in the brain

  • recreational drugs work by increasing or decreasing neurotransmitters at synaptic gap
  • if a drug increases levels of dopamine, user experiences feelings of pleasure or euphoria