Neurochemistry and Drug Action Flashcards
What types of substances can get through the blood-brain barrier?
- by passive diffusion: water, alcohol, nicotine, oxygen, carbon dioxide, nitrous oxide.
- by active transport: glucose, amino acids
- small fat-soluble molecules can get in if not chucked out by extrusion mechanisms
What is depolarisation?
The inside of the cell starts to become more positive than it was
What is hyper-polarisation?
The inside of the cell becomes more negative
What is resting potential?
The electrical potential of a neuron or cell relative to its surroundings when not stimulated
What are the main neurotransmitters and what sort of functions do they participate in?
- GABA: main inhibitory neurotransmitter
- Glutamate: main excitatory neurotransmitter (participated in relay of sensory info)
- Serotonin: mood and temperature
- Dopamine: motor function and reward
- Acetylcholine: muscle contraction and cortical arousal
- Anandamine: pain reduction, increase in appetite
- Norepinephrine: Brain arousal
What are the main ways in which a drug can affect communication between cells at the chemical synapse?
Drug blocks the deactivation of neurotransmitter molecules by blocking degradation or reuptake
Apparently there’s more so go back
Which neurotransmitter’s site does nicotine occupy ?
Nicotinic receptor in the ventral tegmental area
How does nicotine produce a reward?
After it binds to the nicotinic receptor in the VTA, it results in a release of dopamine in the nucleus accumbuns which is linked to reward
What are the main effects of alcohol on neurons in the brain?
It depresses neural firing
What type of neurotransmitter receptors does cannabis target?
- CB1 receptors
- CB2 receptors
- Endocannabinoids
Which neurotransmitters action is affected by cocaine? How?
Blocks dopamine transporters which is responsible for reuptake
Opiate drugs can produce reward (euphoria)- which neurotransmitters are involved in this?
Reward action: GABA (stops dopamine release)
Opiates can also offer analgesic effects. What do they do to cells in the pain pathways to reduce pain transmission?
If the opioid molecule binds to the cell, this will close the calcium channel. Which means that the cell will become more negative. The potassium channels now open so the potassium will leave the cell. Cell becomes too negative to fire so the pain cannot fire to the brain.
