**Core Concept**
Pancuronium and tubocurarine are both non-depolarizing muscle relaxants used in anesthesia to facilitate endotracheal intubation and provide skeletal muscle relaxation during surgery. The primary difference between these two agents lies in their pharmacokinetic and pharmacodynamic properties.

**Why the Correct Answer is Right**
Pancuronium is a long-acting non-depolarizing neuromuscular blocker with a duration of action approximately 60-90 minutes. In contrast, tubocurarine has a shorter duration of action, typically lasting around 30-60 minutes. This difference can be attributed to pancuronium's lower metabolism rate and longer half-life compared to tubocurarine. Additionally, pancuronium has a higher potency and a greater resistance to hydrolysis, which contributes to its longer duration of action.

**Why Each Wrong Option is Incorrect**
**Option A:** Incorrect, as pancuronium and tubocurarine are both non-depolarizing muscle relaxants, and their primary difference is not related to the type of neuromuscular blockade they induce.
**Option B:** Incorrect, as tubocurarine is actually a competitive antagonist at the nicotinic acetylcholine receptor, whereas pancuronium is a competitive antagonist as well, but with a higher affinity for the receptor.
**Option C:** Incorrect, as both pancuronium and tubocurarine can cause histamine release, but pancuronium has a lower incidence of histamine release compared to tubocurarine.

**Clinical Pearl / High-Yield Fact**
It's essential to note that the choice of non-depolarizing muscle relaxant depends on the patient's underlying medical conditions, the surgical procedure, and the anesthesiologist's preference. Additionally, the use of a reversal agent, such as neostigmine, should be considered when reversing the effects of a non-depolarizing muscle relaxant.

**Correct Answer:** D