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Drugs and Synapses

Drugs and Synapses

drugs and synapses

Most drugs affect the nervous system in some way, whether they’re medicinal or recreational. They can have a number of effects on synapses as the table below illustrates.

Action Effect Example
Mimics a neurotransmitterStimulates neurotransmitter release

Opens a neuroreceptor channel

Blocks a neuroreceptor channel

Inhibits enzyme breakdown

Synapse stimulatedSynapse stimulated

Synapse stimulated

Synapse inhibited

Synapse stimulated

LevodopaCaffeine

Alcohol

Opioids

DDT

Drugs are created in order to target specific parts of the nervous system. Those that simulate a synapse are known as agonists while those that inhibit a synapse are called antagonists.

Although you don’t need to know for your exam how specific drugs work it’s important to understand the basics behind how their function.

Drugs Effect Drug type
Caffeine, amphetamines, cocaine, MDMA (ecstasy)Alcohol, barbiturates, marijuana benzodiazepinesCodeine, methadone, morphine, diamorphine (heroin) Stimulate the release of neurotransmitter in excitatory synapses associated with wakefulnessInhibit neuroreceptors in excitatory synapses associated with wakefulnessPrevent the transmission of pain signals to the brain and spinal cord SimulantsTranquilisersNarcotics or opioids

Parkinson’s disease is a result of not enough of the neurotransmitter dopamine being produced in the midbrain. Levodopa, which mimics dopamine, can be used to restore the balance.

Nerve gas and organophosphate insecticides (DDT) inhibit acetylcholinesterase. This means that the acetylcholine receptors located in the neuromuscular junctions are continuously active. This causes the muscles to spasm and results in death.

Hopefully this has helped with your revision on the role of drugs and synapses.