Opioides parte 1 | Aula 36 | Farmacologia do SNC rápida e fácil | Flavonoide

Summary

This pharmacology lesson focuses on opioids, medications primarily used for pain relief. It covers their history, from the discovery of opium to the isolation of morphine, and their mechanisms of action. Opioids interact with specific receptors in the body, such as the mi, kappa, and delta receptors, affecting pain perception and producing both therapeutic and adverse effects, such as respiratory depression. The lesson also highlights the role of endorphins, the body's natural opioids, and examines different types of opioid agonists, including full, partial, and mixed agonists. The video addresses their uses, risks, and the opioid crisis, particularly in the U.S.

Takeaways

• 😀 Opioids are primarily used for the relief of acute and chronic pain, but they also have interesting uses for treating conditions like cough and diarrhea.
• 😀 The history of opioids began with the discovery of opium, which is derived from the poppy plant, leading to the isolation of substances like morphine.
• 😀 Opioids interact with three main classes of opioid receptors: mu, kappa, and delta, which are found in the central nervous system and gastrointestinal tract.
• 😀 Endogenous opioids, such as endorphins, encephalins, and dynorphins, naturally exist in the body and work through opioid receptors.
• 😀 The mu opioid receptors are key to both the desired effects (analgesia) and unwanted effects (such as respiratory depression).
• 😀 Pain transmission involves the brain's processing of signals from neurons, with the thalamus playing a critical role in signal routing.
• 😀 Opioids work by binding to opioid receptors, which modulate ion channels and disrupt pain signal transmission, mimicking the effects of endorphins.
• 😀 There are different types of opioid drugs, such as full agonists (e.g., morphine) that produce a complete response, partial agonists, and mixed agonist-antagonists.
• 😀 Full agonists like morphine are highly effective at relieving pain, with some drugs, like fentanyl, being far stronger and more potent than others.
• 😀 Opioids like codeine, although weaker, have been used for pain relief and as cough suppressants, but their misuse has led to increasing regulation and replacement by drugs like dextromethorphan.
• 😀 Opioids are also used to treat diarrhea, as they slow gastrointestinal transit by activating opioid receptors, though certain opioids like loperamide don’t cross the blood-brain barrier, avoiding central nervous system effects.

Q & A

What are opioids used for?

Opioids are primarily used for the relief of acute and chronic pain. They also have uses in treating conditions like cough and diarrhea.

What are the key types of opioid receptors?

There are three main types of opioid receptors: mu, kappa, and delta. These receptors are found in the central nervous system (brain and spinal cord) and in the gastrointestinal tract.

What are endorphins, and how do they relate to opioids?

Endorphins are endogenous opioids produced by the body. They function in a similar way to opioids, binding to opioid receptors to modulate pain and induce feelings of euphoria.

How do opioids work at the molecular level?

Opioids bind to opioid receptors, particularly the mu receptor. This activates a G-protein mechanism that inhibits calcium channels, reducing neurotransmitter release and preventing pain signals from being transmitted.

What is the significance of the mu opioid receptor?

The mu receptor is the primary target for the effects of most opioids. It is responsible for the analgesic (pain-relieving) effects but also contributes to side effects like respiratory depression.

What role does the thalamus play in the perception of pain?

The thalamus acts as a relay station in the brain. It receives pain signals from the spinal cord and sends them to other parts of the brain, such as the cortex, where the pain is perceived.

Why is fentanil considered the most potent opioid?

Fentanil is considered the most potent opioid because it is 100 times more potent than morphine and 50 times more potent than heroin. It is highly effective for managing severe pain, especially in surgical and post-operative settings.

What are agonists and antagonists in the context of opioids?

Agonists are substances that activate opioid receptors to produce a full effect, while antagonists block these receptors, preventing other opioids from producing their effects. Partial agonists produce a weaker response.

What is the role of opioids in treating diarrhea?

Opioids like loperamide can be used to treat diarrhea. They act on opioid receptors in the gastrointestinal tract to slow down the movement of the intestines, allowing for more water absorption.

What led to the abuse of opioids like codeine in the United States?

The abuse of opioids like codeine increased due to their inclusion in over-the-counter cough syrups, especially in a popular recreational drink called 'lean'. This led to widespread misuse and contributed to the opioid crisis.