Final answer:
Sympathomimetic drugs mimic the effects of sympathetic neurotransmitters like norepinephrine and epinephrine, either by binding to adrenergic receptors or by increasing neurotransmitter release. Examples include phenylephrine, amphetamines, and MDMA (ecstasy). Sympatholytic drugs, in contrast, block these adrenergic receptors to inhibit sympathetic effects.
Step-by-step explanation:
Sympathomimetic Drugs
Sympathomimetic drugs are agents that mimic the effects of the neurotransmitters norepinephrine and epinephrine, stimulating the sympathetic nervous system. These drugs work by either binding to adrenergic receptors to mimic sympathetic activity or increasing the production and release of norepinephrine.
Examples of Sympathomimetic Drugs
One commonly known sympathomimetic drug is phenylephrine, which binds to adrenergic receptors to stimulate target organs. Other drugs include amphetamine and methamphetamine, which notably raise levels of neural activity and are associated with stimulant effects. Moreover, MDMA (ecstasy), with mild stimulant properties, falls under this category as well.
Sympatholytic Drugs
Contrasting to sympathomimetics are sympatholytic drugs, which inhibit the sympathetic nervous system by blocking adrenergic receptors, therefore preventing the binding of norepinephrine and epinephrine. These include various drugs specific to alpha-adrenergic or beta-adrenergic receptors.