hbs 2.1.4-2.1.5

What is Neuropharmacology?

The study of the action of drugs—including medicines and illegal drugs—on the nervous system.

What are action potentials?

Electrical impulses that neurons require to convey information to other neurons.

Which ions are crucial for generating electricity in nerve impulses?

Na^+ and K^+ ions.

How do potassium channels contribute to nerve impulses?

They move K^+ ions from the cell interior to the cell exterior.

How do sodium channels contribute to nerve impulses?

They move Na^+ ions from the cell exterior to the cell interior.

Explain the function of the sodium-potassium pump.

A specialized protein in the cell membrane that:

• Moves Na^+ and K^+ ions back to their starting sites.

• Uses ATP for energy.

• Moves 3 Na^+ ions extracellular for every 2 K^+ ions intracellular.

• Maintains the resting potential by making the outside of the cell more positively charged.

What is the resting potential of a neuron?

The state where the outside of the cell is more positively charged (due to the sodium-potassium pump's action) and the inside is more negative, maintained until the neuron receives a signal.

Describe the depolarization phase of an action potential.

Sodium channels open while potassium channels close, allowing Na^+ ions to rush into the cell. This makes the intracellular space more positive and the extracellular space more negative, passing the electrical signal through the axon.

Describe the repolarization phase of an action potential.

Potassium channels open while sodium channels close, allowing K^+ ions to move out of the cell. This makes the intracellular space more negative and the extracellular space more positive, beginning the return to resting potential.

Name two chemicals used by researchers to inhibit ion channels and their purpose.

1. Tetrodotoxin (TTX): Inhibits sodium channels.
2. Tetraethyl ammonium (TEA): Inhibits potassium channels.

Researchers use these to shut down nervous or muscular electrical activity, study action potential propagation, or isolate effects of other stimuli.

What three components are involved in neuron-to-neuron communication?

The presynaptic cell, synapse, and postsynaptic cell.

Where does neuron-to-neuron communication occur?

In the synaptic cleft, the space within the synapse.

How are neurotransmitters released into the synaptic cleft?

When an action potential reaches the axon terminal, calcium channels open, allowing Ca^{2+} into the cell. This Ca^{2+} then causes vesicles to fuse with the membrane, releasing neurotransmitters.

What is a neuromuscular junction?

The synapse between a neuron and a muscular gland, which activates muscle cells to contract.

Which neurotransmitter is involved in muscle contraction, learning, and memory?

Acetylcholine.

Which neurotransmitter plays a role in pleasure, motivation, mood, attention, memory, and movement?

Dopamine.

What is the primary inhibitory neurotransmitter of the central nervous system, and what is its effect?

GABA (gamma-aminobutyric acid). It slows down the brain by blocking specific signals, leading to feelings of calmness. It causes the neuron's membrane potential to become more negative (hyperpolarization).

What is the primary excitatory neurotransmitter in the brain?

Glutamate, present in more than 90% of all brain synapses.

Which neurotransmitters are involved in the fight-or-flight response?

Epinephrine (adrenaline) and Norepinephrine. They are excitatory neurotransmitters that increase arousal and attention.

What are the functions of Serotonin?

It governs mood, sleep, digestion, nausea, wound healing, blood clotting, and sexual desire.

Distinguish between an inhibitory and an excitatory neurotransmitter.

• Inhibitory: Binds to a receptor and causes the neuron's membrane potential to become more negative (hyperpolarization).

• Excitatory: Binds to a receptor and causes the neuron's membrane potential to become more positive (depolarization).

Define an Agonist drug and provide an example.

A drug that mimics a neurotransmitter and activates the receptor. Example: Morphine.

Define an Antagonist drug and provide an example.

A drug that blocks the receptor and prevents the neurotransmitter from binding. Example: Diphenhydramine.

Define an Inverse Agonist drug and provide an example.

A drug that binds to the same receptor as an agonist but produces an opposite effect to the neurotransmitter. Example: Opioids or Antihistamines.

Define a Reuptake Inhibitor drug and provide an example.

A drug that prevents the reabsorption of neurotransmitters in the synaptic cleft. Example: Cocaine.