Comprehensive Nursing Pharmacology Q 141
Epinephrine is administered to a female patient. The nurse should expect this agent to rapidly affect:
A. Adrenergic receptors.
B. Muscarinic receptors.
C. Cholinergic receptors.
D. Nicotinic receptors.
Correct Answer: A. Adrenergic receptors.
Epinephrine (adrenaline) rapidly affects both alpha and beta adrenergic receptors eliciting a sympathetic (fight or flight) response. Epinephrine (adrenaline) is an endogenous catecholamine with potent ?- and ?-adrenergic stimulating properties. The ?-adrenergic action increases systemic and pulmonary vascular resistance, increasing both systolic and diastolic blood pressure.
Option B: Muscarinic receptors are cholinergic receptors and are primarily located at parasympathetic junctions. Muscarinic receptors are G-coupled protein receptors involved in the parasympathetic nervous system. The only exception to these receptors is the sweat glands, which possess muscarinic receptors but are part of the sympathetic nervous system.
Option C: Cholinergic receptors include muscarinic and nicotinic receptors. Cholinergic receptors respond to acetylcholine stimulation. Cholinergic receptors function in signal transduction of the somatic and autonomic nervous system. The receptors are named because they become activated by the ligand acetylcholine. These receptors subdivide into nicotinic and muscarinic receptors, which are named secondary to separate activating ligands that contributed to their study. Nicotinic receptors are responsive to the agonist nicotine, while muscarinic receptors are responsive to muscarine.
Option D: Nicotinic receptors are cholinergic receptors activated by nicotine and found in autonomic ganglia and somatic neuromuscular junctions. Nicotinic receptors function within the central nervous system and at the neuromuscular junction. The nicotinic receptor subdivides into two subtypes, N1 and N2. N1 may also be referred to as the peripheral or muscle receptor type, while N2 is known as the central or neuronal receptor subtype.