Agonists & Antagonists Drugs [AP Psychology Unit 2 Topic 5]

Summary

In this video, Mr. Sin dives into the influences of drugs on neural firing, continuing the discussion from previous lessons on the nervous and endocrine systems. He explains how agonists, such as Xanax, Prozac, and opioids, enhance neurotransmitter effects by mimicking or increasing neurotransmitter activity. On the other hand, antagonists like certain schizophrenia medications and alcohol block neurotransmitter activity, reducing their effects. The video also covers how reuptake inhibitors prevent neurotransmitter absorption, prolonging their effects. This topic provides valuable insights into the role drugs play in altering brain function and mental health, making it a crucial concept for AP Psychology students.

Takeaways

• 😀 Neurons only fire if there is a strong enough stimulus to trigger an action potential, sending electrical signals through the axon to the axon terminal.
• 😀 Neurotransmitters are stored in synaptic vesicles at the axon terminal and are released to bind to receptors on the postsynaptic neuron.
• 😀 Agonists are substances that enhance the effects of neurotransmitters by mimicking them, increasing their production, or preventing reuptake.
• 😀 Xanax is an example of an agonist that increases the activity of GABA neurotransmitters, helping to calm the nervous system.
• 😀 Prozac is another agonist that blocks the reuptake of serotonin, making it more available to help treat depression.
• 😀 Reuptake inhibitors prevent neurotransmitters from being reabsorbed by the presynaptic neuron, which prolongs their action in the synapse.
• 😀 Opioids are agonist drugs that mimic endorphins, causing a stronger signal than natural endorphins and producing euphoria, but also leading to addiction.
• 😀 Antagonists are drugs that reduce or block neurotransmitter effectiveness by either blocking their release or preventing them from binding to receptors.
• 😀 Medications for schizophrenia often act as antagonists by blocking dopamine receptors to reduce the symptoms of the disorder.
• 😀 Alcohol is an example of an antagonist that blocks the release of glutamate, acting as a depressant and reducing neural activity.

Q & A

What is the role of neurotransmitters in the process of neural firing?

Neurotransmitters are chemicals that transmit signals across the synapse from one neuron to another. When a neuron fires, neurotransmitters are released from the axon terminal and bind to receptors on the postsynaptic neuron, allowing the signal to continue.

What is an agonist substance and how does it affect neurotransmission?

An agonist substance enhances the effect of a neurotransmitter by either mimicking it, increasing its production, or blocking its reuptake. This results in a stronger or longer-lasting signal at the synapse.

Can you give examples of drugs that act as agonists?

Examples of agonist drugs include anti-anxiety medications like Xanax, which increase the effects of GABA neurotransmitters, and antidepressants like Prozac, which inhibit the reuptake of serotonin, making it more available in the brain.

What does 'reuptake' mean in the context of neurotransmission?

Reuptake is the process by which a presynaptic neuron reabsorbs neurotransmitters that were released into the synapse. This process regulates the amount of neurotransmitter available for future transmission.

What is the difference between an agonist and an antagonist drug?

An agonist drug enhances the effect of a neurotransmitter, while an antagonist drug reduces or blocks the effect of a neurotransmitter. Antagonists may block the release of neurotransmitters or prevent them from binding to their receptors.

How do opioid drugs act as agonists?

Opioid drugs mimic the effects of endorphins, which are the body's natural painkillers. They bind to the same receptors and produce a much stronger signal, leading to intense feelings of euphoria, which contributes to their addictive nature.

What is an example of a drug that acts as an antagonist and its effect?

An example of an antagonist drug is medication used to treat schizophrenia, which blocks dopamine receptors, thereby reducing the effects of dopamine in the brain.

What effect does alcohol have on neurotransmission?

Alcohol acts as an antagonist by blocking the release of glutamate, a neurotransmitter that excites neural activity, thus depressing the nervous system and slowing down brain function.

What does it mean for a drug to be a reuptake inhibitor?

A reuptake inhibitor blocks the reabsorption of neurotransmitters into the presynaptic neuron, ensuring that the neurotransmitter remains in the synapse longer and continues to have an effect on the postsynaptic neuron.

Why are opioid drugs particularly addictive?

Opioids are addictive because they mimic endorphins, producing a much stronger sensation of pleasure or euphoria than the body’s natural endorphins. This intense feeling encourages repeated use, leading to addiction.