Recreational drugs, pt. 2
In this lesson, we'll continue our investigation of recreational drugs by covering depressants and opioids. Again, of course, some of these drugs are also used therapeutically.
1) First, watch these videos:
Depressants
Opioids
Kratom is not classified as an opioid, but because it acts on opioid receptors, I will include it here:
2) Next, answer these questions to test your understanding:
1. Alcohol's effects on the brain include increasing activity at GABA receptors and this effect at glutamate receptors:
- A. inhibition of activity at glutamate receptors
- B. increasing activity at glutamate receptors
- C. alcohol doesn't act on glutamate receptors
Show Answer
Correct answer: A
How alcohol acts on the brain is still not completely understood. Two of the best known effects, however, are alcohol's actions on GABA and glutamate receptors. Alcohol increases GABA activity at a subtype of the GABA receptor known as GABAa. And, it inhibits the activity of glutamate receptors.
2. Which of the following receptors is the primary direct target of the benzodiazepines (e.g., Xanax, Klonopin)?
- A. glutamate
- B. serotonin
- C. dopamine
- D. GABA
Show Answer
Correct answer: D
The sedating and anxiety-reducing effects of benzodiazepines are believed to be attributable to the drugs’ actions at receptors for the neurotransmitter gamma-aminobutyric acid, or GABA. By increasing GABA activity, these drugs reduce neural activity, which can help to reduce anxiety by reducing the occurrence of anxiogenic thoughts. Benzodiazepines are no longer a first-line option to treat anxiety, however, because they have a high potential to cause dependence.
3. Kratom's mechanism of action isn't completely understood, but its pain-relieving effects are thought to be at least partially attributable to its actions at this type of receptor:
- A. glutamate receptor
- B. cholinergic receptor
- C. opioid receptor
- D. GABA receptor
Show Answer
Correct answer: C
The active ingredients in kratom are thought to activate opioid receptors involved in pain relief to account for kratom’s analgesic and other opioid-like effects. Some refer to kratom alkaloids as "atypical opioids."
4. The pain-relieving effects of opioids are thought to result, at least in part, from:
- A. increased activity in pain pathways
- B. blocking all sensory input to the brain
- C. a reduction in neuronal activity and neurotransmitter release in pain pathways
- D. increased release of excitatory neurotransmitters in the spinal cord
Show Answer
Correct answer: C
When opioids bind to opioid receptors, they promote potassium conductance, which makes a neuron less likely to fire an action potential, and they inhibit calcium conductance, which makes a neuron less likely to release neurotransmitters. What effect these actions have depends on where the receptors are found. When opioid receptors on neurons in the spinal cord that carry information about pain are activated, it can inhibit the transmission of pain information to the brain.
5. Is fentanyl more or less potent than morphine?
- A. more
- B. less
- C. fentanyl and morphine have similar potency
Show Answer
Correct answer: A
Fentanyl is a highly potent opioid drug that’s approximately 75-100 times more potent than morphine.
