Untitled

**Similarities:**
- Both are adrenergic receptors.
- Both are G-protein coupled receptors.

**Differences:**

**Location:**
- Alpha receptors in blood vessels, smooth muscles, organs.
- Beta receptors in heart, lungs, liver, adipose tissue.

**Subtypes:**
- Alpha: alpha-1 (vasoconstriction) and alpha-2 (inhibit neurotransmitter release).
- Beta: beta-1 (heart rate, contractility), beta-2 (bronchodilation, vasodilation), beta-3 (lipolysis, thermogenesis).

**Response to Agonists:**
- Alpha responds to norepinephrine, epinephrine (variable affinities).
- Beta-1 responds to norepinephrine, epinephrine.
- Beta-2 responds to epinephrine.
- Beta-3 responds to norepinephrine.

**Effects:**
- Alpha regulates blood pressure, vascular tone, blood flow.
- Beta regulates heart rate, cardiac contractility, bronchial relaxation, metabolism.

**Functional Significance:**
- Alpha and beta receptors work together for stress response, exercise, and quick physiological adjustments.