IBDP Biology- Drugs effects on decision making

In this IBDP Biology blog post, we will be looking at how drugs impact the human brain and the way it disrupts its process.

 How psychoactive drugs affect the brain

By disrupting synaptic transmission

• Some have a chemical structure similar to a neurotransmitter and so binds to receptors for that neurotransmitter. --> block the receptors, preventing the neurotransmitter from having its usual effect.
• Others with the same chemical structure have the same effect as a neurotransmitter. However, they are not broken down so when they bind to the receptor --> the effect lasts longer.
• Some interfere with the breakdown of neurotransmitters or the reabsorption into the presynaptic neuron --> prolong the effect of neurotransmitters. 

The effects of THC and Cocaine

THC

• THC is an inhibitory psychoactive drug that decreases synaptic transmission. 
• THC affects synapses where the post-synaptic neuron releases a signal chemical that binds to cannabinoid receptors on pre-synaptic neurons. 
• THC also binds to cannabinoid receptors inhibiting the release of excitatory neurotransmitters from the pre-synaptic neurons. Cannabinoid receptors are found in various brain locations. 
• Cerebellum: THC thus impairs motor functions. 
• Hippocapus: THC thus impairs short-term memory functions. Cerebral cortex: THC thus affects higher order thinking.

Cocaine

• Cocaine is an excitatory psychoactive drugs that increases synaptic transmission. 
• It stimulates transmission at synapses in the brain that use dopamine as a NT. 
• Cocaine binds to membrane proteins that pump dopamine back into the pre-synaptic neurons thus causing a build-up of dopamine in the synapse. 
• Cocaine excites dopaminergic synapses, normally associated with pleasure, thus producing feelings we get when eg,. eating or sex.
• Brain adapts to regular cocaine use by reducing dopamine receptors therefore, cocaine withdrawal often causes depression.  

That is all!

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References:

https://www.google.com/url?sa=i&url=https%3A%2F%2Fwww.nature.com%2Farticles%2Fs41598-020-69454-5&psig=AOvVaw0DwehpWBC38QSenpetZFPB&ust=1627376490098000&source=images&cd=vfe&ved=0CAsQjRxqFwoTCKDNqYCwgPICFQAAAAAdAAAAABAJ

Drafted by Venetia (Biology)