Inflammatory substances produced during allergic reactions by mast cells is

Options

A. Histamine
B. Heparin
C. Serotonin
D. Fibrinogen

Answer

### Step-by-Step Solution:

1. **Understanding Mast Cells**:
- Mast cells are specialized cells that are part of the immune system. They play a crucial role in the body's response to allergens and inflammation.

2. **Role of Mast Cells in Allergic Reactions**:
- During an allergic reaction, mast cells become activated. They release various substances that contribute to the inflammatory response.

3. **Key Substances Released by Mast Cells**:
- The two primary substances produced by mast cells during allergic reactions are **histamine** and **heparin**.

4. **Function of Histamine**:
- Histamine is a potent inflammatory mediator. It causes vasodilation (widening of blood vessels), which increases blood flow to the affected area. This can lead to symptoms such as redness, swelling, and itching.

5. **Function of Heparin**:
- Heparin acts as an anticoagulant, preventing blood from clotting at the site of inflammation. This helps maintain blood flow and allows immune cells to reach the site of the allergic reaction more effectively.

6. **Conclusion**:
- The inflammatory substance primarily responsible for the symptoms of allergic reactions produced by mast cells is **histamine**.