Skeletal muscular relaxant
NM cholinoceptor blocking drugs, also called neuromuscular blocking drugs or skeletal muscular relaxant, can interfere with the transmission of nerve impulses to the skeletal muscle by selectively blocking NM cholinoceptor of skeletal muscular motor-end plate postsynaptic membrane, which manifests as skeletal muscular relaxation. According to its function and characteristics, it can be divided into the depolarizing muscular relaxant and the non-depolarizing muscle relaxant.
Part one Depolarizing muscular relaxant
Also known as non-competitive muscle relaxants, the drug combines with its receptor continuously, which makes the receptor cannot deliver more nerve impulses. As time goes on, sustained depolarization transforms into stable repolarization because the sodium channel is closed or blocked. Consequently, depolarization reversal happens and the action potential which arrives after that cannot be reacted. As a result, the transmission of nerve impulses is blocked, which manifest as skeletal muscular relaxation. At present, clinically succinylcholine is most commonly used among this kind of medicine.
Part two Non-depolarizing muscle relaxant
Also called competitive muscular relaxants, it can competitively combine with NM cholinoceptor of the skeletal muscular motor-end plate. Although itself has no intrinsic activity which can excite the receptor to produce depolarization, it can block the ACh to combine with the receptor and generate the depolarization effect to relax skeletal muscle. This kind of drugs mainly includes atracurium, mivacurium, doxacurium and so on. The kind of Steroid amines drugs includes ammonium steroids pancuronium, pipecuronium, rocuronium and vecuronium and so on.