brain chemicals

• Parkinson's disease


  Muscle tremors (shakes); stiffness of muscles and slowness of movement; poor balance and walking problems; difficulties with speech and breathing; depression
• Parkinson's disease


  Associated with the death of a group of dopamine-secreting neurons in the brain, resulting in the reduction of dopamine levels
• Dopamine


  A neurotransmitter that is active in neurones in the frontal cortex, brain stem and spinal cord, associated with the control of movement and emotional responses
• Treatment of Parkinson's disease


  1. Increase the concentration of dopamine in the brain

  2. Use L-dopa (the molecule used to make dopamine) to help control the symptoms
• Serotonin


  A neurotransmitter linked to feelings of reward and pleasure
• Depression


  Prolonged feelings of sadness, anxiety, hopelessness, loss of interest, restlessness, insomnia
• Lack of serotonin


  Linked to clinical depression
• Ecstasy (MDMA)


  Works by preventing the reuptake of serotonin, maintaining a high concentration of serotonin in the synapse, which brings about the mood changes in the users
• Serotonin selective reabsorption inhibitor (SSRI)


  Prozac is an example, it binds to reuptake proteins so serotonin is not reabsorbed, resulting in a high level of serotonin in the synapses
• How drugs affect the nervous system


  1. Affect the synthesis or storage of the neurotransmitter

  2. Affect the release of the neurotransmitter from the presynaptic membrane

  3. Affect the interaction between the neurotransmitter and the receptors on the postsynaptic membrane

  4. Be stimulatory by binding to the receptors and opening the sodium ion channels

  5. Be inhibitory, blocking the receptors on the postsynaptic membranes and preventing the neurotransmitters binding

  6. Prevent the reuptake of the neurotransmitter back into the presynaptic membrane

  7. Inhibit the enzymes involved in breaking down the neurotransmitter in the synaptic cleft
• Dopamine agonists


  Have a similar shape to dopamine
• Dopamine agonists that mimic dopamine might be a useful treatment for Parkinson's disease, as patients with Parkinson's disease have little of the neurotransmitter dopamine in their brains