E4 Neurotransmitters and Synapses

Question 1

Explain how psychoactive drugs affect the brain and personality

Answer 1

• Psychoactive drugs may either increase postsynaptic transmission (stimulants) or decrease postsynaptic transmissions (depressants)
  
  • Stimulants produce psychomotor arousal and increased alertness, whereas depressants slow down brain activity and relax muscles
  • Both act primarily on the CNS and can cause a chemical dependency, leading to substance abuse and addictions

Question 2

List three excitatory psychoactive drugs

Answer 2

Cocaine, Amphetamines, Nicotine

Question 3

List three inhibitory psychoactive drugs

Answer 3

Benzodiazepines (BZD), Alcohol, THC

Question 4

Explain the effects of THC in terms of its effect on synapses in the brain

Answer 4

• Before THC enters the system, neurotransmitters are released into the synapse which inhibit the release of dopamine
  
  • THC mimics the neurotransmitter anandamide by binding to cannaboid receptors, preventing the release of this inhibitory neurotransmitter
  • This allows dopamine to be released into the synapse

Question 5

Explain the effects of Cocaine in terms of its effect on synapses in the brain

Answer 5

• Dopamine transporters remove dopamine from the synaptic clef after they have done their job
  
  • Cocaine blocks, these transporters, leaving dopamine trapped in the synaptic clef
  • As a result, dopamine binds repeatedly to the receptors, overstimulating the neuron

Question 6

Discuss the causes of addiction, including genetic predisposition, social factors and dopamine secretion

Answer 6

Genetic
• Possible genetic predisposition to addition
Social
• Alcohol problems among family members
• Poor school performance
• Stress
• Having friends who drink
Dopamine and addition
• Dopamine is a chemical in the brain that is associated with pleasure and reward
• Substances with addictive potential stimulate the release of dopamine
• Substance use causes a flood of dopamine, which alters the chemistry of the brain