d-Tubocurarine -Mechanism of action:
Ref. KDT. Page. 352
d-TC

The competitive blockers have affinity for the nicotinic (NM) cholinergic receptors at the muscle end plate, but have no intrinsic activity
Most of the competitive blockers have two or more quaternary N+ atoms which provide the necessary attraction to the same site, but the bulk of the antagonist molecule does not allow conformational changes in the subunits needed for opening the channel
d-TC thus reduces the frequency of channel opening but not its duration or the conductance of a channel once it has opened.
The competitive blockers also block prejunc- tional nicotinic receptors located on motor nerve endings
Competitive, nondepolarizing block at the Nm cholinergic receptors
Noncompetitive, nondepolarizing block at the Nm cholinergic receptors
Competitive, depolarizing block at the Nm cholinergic receptors
Noncompetitive, Depolarizing block at the Nm cholinergic receptors