Cannabinoid receptors are principle present in

Options

A. Brain
B. Bone marrow
C. Muscles
D. Gonads

Answer

To determine where cannabinoid receptors are principally present, let's analyze the options provided:

1. **Understanding Cannabinoid Receptors**: Cannabinoid receptors are specialized proteins that respond to cannabinoids, which are compounds found in cannabis as well as produced naturally in the body (endocannabinoids).

2. **Identifying Locations**: Cannabinoid receptors are distributed throughout the body, including in various organs such as the liver, kidneys, and lungs. However, their primary function is closely associated with the nervous system.

3. **Nervous System Connection**: The cannabinoid receptors play a significant role in regulating various functions of the nervous system, including mood, memory, and sensory perception.

4. **Evaluating the Options**:
- **Brain**: The brain is a central organ of the nervous system and is heavily involved in processing the effects of cannabinoids. This is where the majority of cannabinoid receptors are concentrated, making it the principal site of their action.
- **Bone Marrow**: While bone marrow has various receptors, it is not known for a significant presence of cannabinoid receptors.
- **Muscle**: Cannabinoid receptors are not primarily associated with muscle tissue.
- **Gonads**: Although cannabinoid receptors can be found in gonadal tissues, they are not the principal site of action.

5. **Conclusion**: Based on the analysis, the correct answer is that cannabinoid receptors are principally present in the **brain**.

### Step-by-Step Solution:
1. Identify what cannabinoid receptors are and their function.
2. Recognize that they are distributed throughout the body.
3. Understand their primary role in the nervous system.
4. Evaluate each option to determine where cannabinoid receptors are most concentrated.
5. Conclude that the principal location of cannabinoid receptors is the brain.