**Question:** Amphetamine causes which of the following -

A. Increased heart rate
B. Depression of the central nervous system
C. Increased blood pressure
D. Hypersalivation

**Core Concept:** Amphetamines are a class of psychostimulant drugs that exert their effects by increasing the levels of neurotransmitters (e.g., dopamine, norepinephrine, and serotonin) in the brain.

**Why the Correct Answer is Right:** Amphetamines primarily target the central nervous system (CNS) and increase the release of neurotransmitters, particularly dopamine and norepinephrine. As a result, they lead to the following effects:

1. **Increased heart rate (Correct Answer A):** Amphetamines increase the rate at which the heart beats to deliver more oxygen and nutrients to the body's tissues, which is clinically relevant in conditions like fatigue, obesity, or narcolepsy.
2. **Depression of the central nervous system (Option B):** Although amphetamines increase CNS activity initially, prolonged use can lead to neuroadaptation and tolerance, resulting in a depressive effect on the CNS.
3. **Increased blood pressure (Correct Answer C):** Similar to increased heart rate, amphetamines elevate blood pressure to improve oxygen and nutrient delivery to tissues but may lead to hypertension in some cases.
4. **Hypersalivation (Option D):** Amphetamines can cause excessive salivation due to their effects on the autonomic nervous system.

**Why Each Wrong Option is Incorrect:**

5. **Depression of the central nervous system (Option B):** As mentioned earlier, prolonged amphetamine use results in neuroadaptation and tolerance, leading to a depressive effect on the CNS. This is not a direct consequence of amphetamine administration.
6. **Hypersalivation (Option D):** Although amphetamines do increase salivation, the effect is not as significant as other options and is not typically listed as a direct consequence of amphetamine use.
7. **Increased heart rate (Option C):** While amphetamines do increase heart rate, the correct answer is option A, which emphasizes the immediate impact on cardiovascular system.
8. **Increased blood pressure (Option C):** As mentioned, amphetamines increase blood pressure to improve tissue perfusion, but option A emphasizes the primary effect on the cardiovascular system.

**Clinical Pearl:** While amphetamines have various physiological effects, it is essential to understand that certain symptoms may not be present in all cases or may not be the primary outcome of amphetamine use. A clear understanding of the core effects is crucial to accurately diagnose and manage patients with amphetamine-induced symptoms.