drugs on synapses

• drugs can increase transmission of impulse

  • causing more neurotransmitter to be produced in synaptic knob
  • more NT is released at presynaptic membrane
  • imitating effect of NT-binding to and stimulating post synaptic neurone receptors
  • prevent the break down of NT by enzymes
  • prevent reuptake of NT by presynaptic cell
• drugs can decrease transmission of impulse

  • prevent production of NT in knob/limiting release of NT in presynaptic membrane
  • binding to receptors in post synpatic membrane so preventing NT from binding
  • allowing NT to leak out of knob gradually-so little is left when AP arrives- NT that leaks out is destoyed by enzymes
• example- MDMA(ectasy)

  • MDMA effects multiple neurotransmitters- mainly serotonin
  • MDMA inhibits the reuptake of serotonin into presynaptic neuroneby binding to specific proteins which enable reuptake=increase serotonin in brain
  • also triggers release of more serotonin

  symptoms=extreme euphoria, enhanced touch and bodily sensation
• L-dopa

  • transported via blood to brain, converted into dopamine in reaction catalysed by dopa-carboxylase
  • increases levels of dopamine in brain
  • so more nerve impulses are transmitted in parts of the brain which control movement=better control of movement