What is a primary action of drugs with the suffix "lytic" or "blocker"?

Drugs with the suffix "lytic" or "blocker" are primarily known for their ability to inhibit or block the effects of certain neurotransmitters in the body. This action typically involves preventing the neurotransmitters from binding to their receptors, thereby interfering with the normal communication pathways in the nervous system.

For instance, adrenergic blockers, such as beta-blockers, suppress the actions of norepinephrine and epinephrine at the adrenergic receptors, leading to outcomes such as lowered heart rate and decreased blood pressure. Likewise, other categories of blockers may target different neurotransmitter systems, such as the inhibition of acetylcholine's action at muscarinic receptors in the case of certain cholinergic antagonists.

The other choices do not accurately describe the primary action of "lytic" or "blocker" drugs. Blocking contraction of skeletal muscles relates more to neuromuscular blockers, while being bio-identical to acetylcholine does not align with the blocking action. Similarly, dilating the synapse between nerves does not describe the fundamental inhibitory role of these classes of drugs. Thus, the correct answer emphasizes the blocking mechanism as the defining characteristic of drugs categorized as "lytic" or "blocker".