Final answer:
Mrs. Peters' epinephrine has a sympathomimetic effect because it enhances the normal function of the beta-2 adrenergic receptors, leading to smooth muscle relaxation and bronchodilation.
Step-by-step explanation:
Mrs. Peters suffers an acute bronchospasm and receives epinephrine. This drug enhances the normal physiologic function of its beta-2 receptor to stimulate bronchodilation. No new function was developed as a result. Mrs. Peters' epinephrine has a sympathomimetic effect.
Epinephrine reacts with alpha (α) and beta (β) adrenoreceptors, causing vasoconstriction and vasodilation respectively. While receptors are less sensitive to epinephrine, activation by high levels primarily causes vasoconstriction. Conversely, lower levels promote vasodilation by stimulating β-adrenoreceptor. Sympathomimetic drugs like epinephrine mimic the actions of adrenergic molecules, enhancing sympathetic system functions by binding to adrenergic receptors.
The β2-adrenergic receptor subtype is specifically responsible for smooth muscle relaxation, such as in the bronchi, making it crucial in treating bronchospasm conditions. Epinephrine, by acting as a sympathomimetic agent, activates these receptors leading to relaxation of the bronchial muscles and alleviating symptoms of bronchospasm.