Which type of drugs block adrenergic receptors and produce the opposite effect of the sympathetic nervous system?

Antiadrenergic drugs are designed to block adrenergic receptors, which are involved in the sympathetic nervous system's response. By inhibiting these receptors, antiadrenergic drugs counteract the effects typically produced by sympathetic stimulation, such as increased heart rate, blood pressure elevation, and increased blood flow to muscles.

This class of drugs interacts with either alpha or beta adrenergic receptors, which play distinct roles in physiological responses. For instance, by blocking beta-1 receptors in the heart, antiadrenergic drugs can reduce heart rate and myocardial contractility, which is beneficial in conditions such as hypertension or certain types of heart disease. Blocking alpha receptors can lead to vasodilation and reduced blood pressure.

The other types of drugs listed do not have the same mechanism of action. Adrenergic drugs would stimulate the sympathetic system, cholinergic drugs typically act within the parasympathetic nervous system by mimicking acetylcholine, and anticholinergic drugs block the actions of acetylcholine, also influencing parasympathetic responses. Hence, antiadrenergic drugs most accurately fit the description of blocking adrenergic receptors and opposing sympathetic effects.