Which of the following may be attributed to the effects of endogenous opioids?

• A. Reduction in pain perception
• B. Increased heart rate
• C. Impaired memory formation
• D. Heightened anxiety

Answer: (A)

Verified step by step guidance

1. Step 1: Understand what endogenous opioids are. These are naturally occurring chemicals in the brain, such as endorphins, that bind to opioid receptors and influence various physiological and psychological processes.
2. Step 2: Recognize the primary function of endogenous opioids, which is to modulate pain and produce analgesia (pain relief). They act as natural painkillers by reducing the perception of pain.
3. Step 3: Evaluate each option in the context of endogenous opioid effects: Reduction in pain perception aligns with their analgesic role; increased heart rate is typically not associated with opioid activity; impaired memory formation is more related to other neurotransmitter systems; heightened anxiety is generally not caused by endogenous opioids, which often have calming effects.
4. Step 4: Conclude that the effect most directly attributed to endogenous opioids is the reduction in pain perception, as this is their well-established physiological role.
5. Step 5: Summarize that endogenous opioids primarily function to decrease pain sensation and promote feelings of well-being, which explains why 'Reduction in pain perception' is the correct answer.