Neurotransmitters

• Neurotransmitters are chemicals transported from the pre-synaptic to post-synaptic neuron across the synaptic cleft via electrical impulses
• Neurotransmitters are transferred when an action potential excites the pre-synaptic neuron, sending an electrical impulse past the synaptic vesicles holding the neurotransmitters, then gets released into the synaptic cleft
• Excess neurotransmitters that aren't passed across the synaptic cleft are taken back up by the presynaptic neuron. This is known as reuptake.
• Synapses are be excitatory, meaning it increases probability of an action potential occurring in the post-synaptic neuron.
• Synapses are be inhibitory, meaning it decreases probability of an action potential occurring in the post-synaptic neuron.
• Examples of neurotransmitters are dopamine and serotonin.
• Dopamine is part of a group of neurotransmitters called monoamines. Brain regions/structures associated with dopamine production are the ventral tegmental area and the caudate nucleus.
• Dopamine is a chemical messenger that communicates between cells from the brain to the rest of the body. It's strongly associated with reward, motivation, intense pleasure and hence addiction.
• Irregular levels of dopamine have been linked to schizophrenia symptoms
• Fisher et al (2005) focuses on effect of neurotransmitters on behavior because it studies the link between early stage romantic love and dopaminergic activity in the brain
• An agonist is a molecule that binds to a synaptic receptor and "activates it" to promote a reaction. Drugs can be agonists, affecting the degree of a neurotransmitter's effect. If a drug like an antidepressant increases the effect of a neurotransmitter like serotonin, it's an agonist.
• Selective serotonin uptake inhibitors (SSRIs) are agonists since they prevent the re-absorption of serotonin back into the presynaptic neuron and increases the amount of serotonin available. SSRIs are usually for treating depression but also anxiety disorders like OCD and PTSD
• Antagonists are molecules that bind to a synaptic receptor and decrease the neurotransmitter's effect. Drugs can also be antagonists, blocking the receptor so the neurotransmitters can't bind to the post-synaptic neuron. Dopamine agonists can treat drug addiction, schizophrenia, etc.