Synaptic transmission and how it is affected by drugs

| SYNAPTIC TRANSMISSIONDescribe what takes place in the synaptic transmission, What neurotransmitters and ions are involved? |
TYPE OF DRUG | WITHOUT THE DRUG | WITH THE DRUG |
1. Cannabis(marihuana) | Without the drug, the synaptic transmission would normally work like this: the presynaptic neuron would release neurotransmitters trough the synaptic channels that would bind in the ions inthe postsynaptic neuron. | Anandmide molecules normally attach to the receptors in the brain and this molecule is involved in regulating mood, memory, appetite, pain, cognition, and emotions but whencannabis is introduced into the body, its active ingredient, Delta-9-tetrahydrocannabinol (THC), can therefore interfere with all of these functions. Then THC begins to bind to another receptors andthese receptors affect the activity of several enzymes. The general excitability of the brain’s neural networks is thus reduced as well.  |
2. Alcohol | | Alcohol inhibits the neurotransmission in twoways: inhibits the excitatory channels in the postsynaptic neuron and lowers the rate of action potentials in the presynaptic neuron. It also binds directly to the receptors for acetylcholine(excitatory neurotransmitter), serotonin (involved with mood, appetite, sensory perception and it also blocks pain pathways), GABA (major inhibitory neurotransmitter in the brain), and the NMDA receptors forglutamate (most common excitatory neurotransmitter in the brain). It also increases the levels of dopamine even though is lowers the secretion of the enzyme that breaks down dopamine. |
3.Nicotine | | This drug blocks the reuptake of dopamine, norepinephrine and serotonin by the presynaptic neuron and this leads to a higher concentration of dopamine in the synapse, which excites the neuronsto fire action potentials. |
4. Caffeine | | Caffeine inhibits sleepiness by blocking adenosine neurotransmission and increases the nervous activity by the withdrawal of this molecule. |
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