Neurotransmitters and Their Functions

Study Notes

Neurotransmitters & their roles

Acetylcholine: plays a vital role in muscle contraction, learning, and memory.
Glutamate: the primary excitatory neurotransmitter in the brain, responsible for over 90% of brain synapses.
Dopamine: associated with pleasure, motivation, mood, attention, memory, and movement.
Epinephrine & Norepinephrine: excitatory neurotransmitters that play a key role in the "fight or flight" response by increasing arousal and attention.
Gamma Aminobutyric Acid (GABA): the primary inhibitory neurotransmitter in the central nervous system, crucial for regulating signals and maintaining normal brain function.

Excitatory & Inhibitory Postsynaptic Potentials (EPSPs & IPSPs)

EPSPs: triggered by neurotransmitters like glutamate, leading to sodium ion (Na+) influx, resulting in membrane depolarization and excitation.
IPSPs: caused by neurotransmitters like GABA, leading to chloride ion (Cl-) influx, causing membrane hyperpolarization and inhibition.

Role of Potassium (K+) in Action Potential Termination

Potassium ions (K+) play a critical role in repolarizing the neuronal membrane after an action potential, returning it to its resting state.

Receptor Modes of Action

Agonist: binds to a receptor and activates it, triggering a response.
Antagonist: binds to a receptor but blocks its activation, preventing it from responding.
Inverse Agonist: binds to a receptor and produces an opposite effect to an agonist, suppressing receptor activity.
Reuptake Inhibitor: blocks the reuptake of neurotransmitters from the synapse, prolonging their effects.

Examples of Drugs and their Receptor Interactions

Diphenhydramine: acts as an inverse agonist.
Morphine: acts as an agonist.
Caffeine: acts as an antagonist.
Cocaine: acts as a reuptake inhibitor.

Reflex vs. Voluntary Reactions

Reflexes: are faster than voluntary reactions.

Differential Diagnosis

A differential diagnosis is a list of possible diagnoses, arranged from the most likely to the least likely, based on the patient's symptoms.

Presenting a Patient / "Rounds"

Key information to include:
- Age
- Sex
- Occupation (if relevant)
- Chief concern / Presenting problem
- Patient's subjective sense of improvement or worsening
- Vital signs / physical exam findings
- Summary of procedures, drugs, scans, etc.
- Proposed next steps

Neurological Diseases and Their Associated Neurotransmitters

Devic's Disease: affects interneurons, causing vision loss.
Epilepsy: affects interneurons, leading to seizures.
Fibromyalgia / Central Sensitization Syndrome: affects sensory neurons, causing widespread chronic pain and hypersensitivity.
Alzheimer's Disease: affects interneurons, contributing to memory loss and cognitive decline.
Multiple Sclerosis: affects sensory neurons, leading to symptoms like pins and needles, weakness, and fatigue.
Parkinson's Disease: affects interneurons, resulting in tremors, rigidity, and slow movements.
Charcot-Marie-Tooth Disease: affects sensory neurons, causing muscle loss, weakness, and nerve damage.
Huntington's Disease: affects interneurons, causing progressive brain degeneration and neurological decline.
Amyotrophic Lateral Sclerosis (ALS): affects motor neurons, causing progressive muscle weakness and paralysis.

In Vivo vs. In Vitro

In Vivo: experiments are performed on living organisms, including animal cells.
In Vitro: experiments are conducted in controlled environments outside of living organisms, using isolated animal cells.

Serotonin

Plays a crucial role in regulating mood and sleep, as well as digestion.

Description

This quiz explores the various neurotransmitters and their critical roles in brain function and behavior. It covers excitatory and inhibitory postsynaptic potentials, detailing how these neurotransmitters influence learning, memory, and the body's response to stress. Test your knowledge on this essential neuroscience topic!