What are the ways that drugs can affect synaptic transmission?
2 Answers
Our body produces natural chemicals such as hormones and neurotransmitters, these chemicals assist or prevent synaptic transmissions.
Explanation:
Drugs are made of man-made chemicals, All of these chemical, can imitate how our hormones and neurotransmitters work. These chemicals vary on how they affect a person synaptic transmission, some of them, can speed up synaptic transmissions, some can slow down them down, some can block them from transmitting, while some can even cause chemical reaction, causing our natural chemical to affect us differently.
Three main ways: affect the number of neurotransmitters available, the rate of release of neurotransmitters, and binding affinity of neurotransmitter receptors to the neurotransmitters.
Explanation:
I am not too familiar with specific drugs. The following article will describe how they can be affected, and what enzymes/chemicals are available to cause changes. These are not necessarily pharmaceutical drugs.
So I said there are three main ways of drugs affecting synaptic transmission.
Let's go into detail for each one:
Availability of neurotransmitters
Drugs can affect the production of neurotransmitters, movement of neurotransmitters into vesicles, or movement of vesicles to a synapse.
Example:
- Hydrazinopropionic acid inhibits biosynthesis of GAD enzyme required for GABA biosynthesis.
Rate of release of neurotransmitters
Neurotransmitters are released into the synapse via exocytosis. Exocytosis is a complicated process requiring many structural proteins such as SNARE proteins. Selectiveness of exocytosis is also a contributive factor.
Examples:
- TAT-NSF polypeptide inhibits SNARE proteins, disabling exocytosis.
- Tetanus toxin is a specific inhibitor of VAMP3/cellubrevin (one of
SNARE proteins).
Affinity of neurotransmitter receptors
Drugs that affect the receptors' affinities is probably the most well-known type because they are even mentioned in usual college textbooks. They are also the most common type of recreational drugs.
Examples:
- Cocaine inhibits dopamine transporter (DAT), saturating the central nervous system with dopamine and overclocking the reward pathway.
- Antipsychotic drugs such as Quetiapine affect both dopamine and serotonin receptors and are used for treating Schizophrenia and bipolar disorder.
- NMDA receptor antagonists are a class of anesthetics used on both animals and humans.
Sources:
http://www.ncbi.nlm.nih.gov/pubmed/15778265
http://www.ncbi.nlm.nih.gov/pubmed/15777788
https://en.wikipedia.org/wiki/Dopamine_receptor
https://en.wikipedia.org/wiki/Antipsychotic#Schizophrenia
http://ocw.mit.edu/ans7870/SP/SP.236/S09/lecturenotes/drugchart.htm
http://www.auburn.edu/~deruija/GABA_Intro2002.pdf
