This document discusses neuromuscular blocking agents and disorders of the neuromuscular junction. It describes how neuromuscular blockers like curare, bungarotoxin, succinylcholine, and botulinum toxin work by blocking neuromuscular transmission at the motor end plate. It also discusses neuromuscular stimulators like methacholine and drugs that inhibit cholinesterase. Finally, it summarizes two disorders: myasthenia gravis, an autoimmune disease where antibodies destroy acetylcholine receptors, and Lambert-Eaton syndrome where antibodies affect calcium channels and acetylcholine release.

1. PHARMACOLOGY-I
Session 2020-21
Submitted by –
Mr. Suyash Jain
Department Of Pharmaceutical Sciences
Dr. Harisingh Gour Vishwavidyalaya, Sagar (M.P.)
Neuromuscular blocking agents
( A Central University )

2. INTRODUCTION
Neuro-muscular
junction/Myoneural
junction/Motorend
plate.
Junctionbetween Motor
neuron & Muscle fibre.
Action potential from
nerve is transmitted to
muscle through this
junction.

3. DRUGS AFFECTING
NEUROMUSCULAR JUNCTION.
Neuromuscular
Blockers–this block
neuromuscular
transmission at
junction.
Curare
Bungarotoxin
Succinylcholine and
carbamylcholine
Botulinum toxin

4. NEUROMUSCULAR BLOCKERS
Curare–active
principle D-
Tubocurarine (Cobra)
Block by combine with
Ach-receptors.
So Ach cannot act on
receptors & NoEnd
PlatePotential develop
So these are receptor
blockers.

5. NEUROMUSCULAR
BLOCKERS
Bungarotoxin –
Venomof deadly snake.
Krait.
Also block N-Mjunction
by combiningwith
acetylcholine
receptors.

6. NEUROMUSCULARBLOCKERS
Succinylcholine&
Carbamylcholine–act like
acetyl choline & Depolarizes
post synaptic membrane
But these are not destroyed by
cholinesterase –so muscle
remain in depolarized state for
a long time.
So these blockMyoneural
junctionby keepingthe
muscleindepolarized state.

7. NEUROMUSCULARBLOCKERS
BotulinumToxin–
derived from bacteria
Clostridium
Botulinum.
Block the junction by
preventing the
ReleaseOfAcetyl
Cholinefrom terminal
button.

8. NEUROMUSCULAR
STIMULATORS
Drugs having acetylcholine like action-
Methacholine,Carbachol& Nicotin
But these are either not destroyed or destroyedvery
slowly by acetylcholinesterase so causes repeated
stimulation & continuous action of muscle –Muscle
spasm.

9. NEUROMUSCULAR
STIMULATORS
Drugs that Inactivatethe enzyme Cholinesterase
(Anticholinesterase)–Neostigmine,
Physostigmine&Disopropylflurophosphate
(DFP)
So it leads to repeated stimulation & continuous action of
muscle. E.g–Laryngeal Spasm.

10. DISORDERSOF
NEUROMUSCULARJUNCTION.
MyastheniaGravis
AutoImmunedisease.
Antibodies are
produced against
Acetylcholine
Receptors& destroy
these channels

11. DISORDERSOF
NEUROMUSCULARJUNCTION.
So acetyl choline
released will not
produceadequate
endplate potential &
excite muscle fibre
So patient dies of
paralysis of
RespiratoryMuscles.

12. DISORDERSOF
NEUROMUSCULARJUNCTION.
Lambert-Eaton
syndrome.
Antibodies are
produced against
calciumchannels
present on pre-synaptic
membrane –so Ca
influxdecrease &
decreases release of
acetyl choline

14. Thank You