What is a characteristic of antagonistic drugs?

Antagonistic drugs are defined by their ability to block the effects of specific neurotransmitters. This characteristic is fundamental to understanding how these drugs function in the body. When an antagonist binds to a receptor, it prevents the normal neurotransmitter from engaging with that receptor, thereby inhibiting its action. This can lead to a reduction or cessation of the physiological effects that would typically occur if the neurotransmitter were able to activate the receptor.

For instance, if a neurotransmitter is responsible for promoting muscle contraction, an antagonist would bind to the receptor designated for that neurotransmitter, counteracting its effects and potentially leading to muscle relaxation. This mechanism is crucial in various therapeutic contexts, such as managing conditions like anxiety, hypertension, or gastrointestinal issues.

The other options describe actions not associated with antagonistic drugs. Activating receptors would be characteristic of agonists, while enhancing the effects of neurotransmitters suggests a facilitative action rather than a blocking one. Lastly, the statement about acting only on skeletal muscles is too narrow, as antagonists can have broader applications across different organ systems and neurotransmitter pathways.