In humans, receptors for opioids are present in

Options

A. central nervous system
B. gastrointestinal tract
C. respiratory tract
D. both (1) and (2)

Answer

To answer the question about where opioid receptors are present in humans, we can break down the information as follows:

### Step-by-Step Solution:

1. **Understanding Opioids**:
- Opioids are a class of drugs that include both natural and synthetic substances. They are known for their pain-relieving properties and their ability to produce feelings of euphoria.

2. **Identifying Receptors**:
- In the human body, opioid receptors are specific sites that opioids bind to in order to exert their effects.

3. **Location of Opioid Receptors**:
- Opioid receptors are primarily found in two main areas:
- **Central Nervous System (CNS)**: This includes the brain and spinal cord, where opioids can affect pain perception, mood, and various bodily functions.
- **Gastrointestinal Tract**: Opioid receptors are also present in the digestive system, where they can influence gut motility and other functions.

4. **Conclusion**:
- Based on the information, we can conclude that opioid receptors are present in both the central nervous system and the gastrointestinal tract.

5. **Final Answer**:
- Therefore, the correct answer to the question is option D: both 1 (Central Nervous System) and 2 (Gastrointestinal Tract).