Smulation of target organs by the parasympathetic vagus nerve would exert which of the following effects ?

Options

A. Acetylcholine inhibition of the GI tract
B. Norepinephrine-stimulated increase in the heart rate
C. Norepinephrine inhibition of pancreatic secretion
D. Acetycholine-stimulated increase in pancreatic secretion

Answer

To answer the question regarding the effects of stimulation of target organs by the parasympathetic vagus nerve, we can follow these steps:

### Step-by-Step Solution:

1. **Understand the Role of the Vagus Nerve**: The vagus nerve is a major component of the parasympathetic nervous system. It is responsible for promoting "rest and digest" functions in the body.

2. **Identify the Neurotransmitter**: The primary neurotransmitter used by the parasympathetic nervous system, including the vagus nerve, is acetylcholine. This neurotransmitter has various effects on target organs.

3. **Analyze Each Option**:
- **Option 1**: "Acetylcholine inhibition of the GI tract" - This is incorrect because the vagus nerve stimulates the GI tract, not inhibits it.
- **Option 2**: "Norepinephrine stimulated increase in the heart rate" - This is also incorrect because norepinephrine is associated with the sympathetic nervous system, which increases heart rate, opposing the vagus nerve's action.
- **Option 3**: "Norepinephrine inhibition of the pancreatic secretion" - This is incorrect as norepinephrine is related to sympathetic responses, not parasympathetic.
- **Option 4**: "Acetylcholine stimulated increase in pancreatic secretion" - This is correct. The vagus nerve stimulates pancreatic secretion through acetylcholine.

4. **Conclusion**: Based on the analysis, the correct answer is **Option 4: Acetylcholine stimulated increase in pancreatic secretion**.