The autonomic nervous system (ANS) carries nerve impulses from the central nervous system to effector organs via two types of neurons - preganglionic and postganglionic. Preganglionic neurons originate in the CNS and synapse in peripheral ganglia, while postganglionic neurons innervate effector organs. Acetylcholine is the main neurotransmitter of the parasympathetic division and some parts of the sympathetic division. It is synthesized locally and broken down by acetylcholinesterase. Cholinergic drugs like pilocarpine and edrophonium act by either directly activating cholinergic receptors or indirectly by inhibiting acetylcholinesterase. Atropine is a competitive mus
6. Working of ANS
• Efferent neurons The ANS carries nerve impulses
from the CNS to the effector organs by way of two
types of efferent neurons: the preganglionic
neurons and the postganglionic neurons
• The cell body of the first nerve cell, the
preganglionic neuron, is located within the CNS
7.
8. • The preganglionic neurons emerge from the
brainstem or spinal cord and make a synaptic
connection in ganglia (an aggregation of nerve cell
bodies located in the peripheral nervous system)
• The ganglia function as relay stations between the
preganglionic neuron and the second nerve cell,
the postganglionic neuron
• The cell body of the postganglionic neuron
terminates on effector organs, such as smooth
muscles of the viscera, cardiac muscle, and the
exocrine glands
9.
10. Cholinergic transmission
• Acetylcholine Neurotransmitter at
1. Neuromuscular junction (NMJ)
2. All preganglionic neurons
3. All postganglionic parasympathetic neurons
4. Postganglionic sympathetic neurons in sweat
glands
11.
12. Synthesis, storage and destruction
of ACh
• Synthesized locally in the cholinergic nerve endings
13. Cholinesterase
• 2 types:-
1. Acetylcholinesterase—AChE or true
cholinesterase
2. Butyrylcholinesterase—BuChE or pseudochE
25. Pilocarpine
• Obtained from the leaves of Pilocarpus microphyllus
and other species
• Prominent muscarinic action (M3) & mild nicotinic
action at ganglia (NN)
• Applied to the eye, it penetrates cornea and
promptly causes miosis, ciliary muscle contraction
and fall in intraocular tension lasting 4–8 hours.
• Uses Open angle glaucoma, xerostomia
• S/E Initial stinging sensation in the eye and painful
spasm of accommodation, marked sweating,
salivation and ↑ in other secretions
26. Edrophonium
• Resembles Neostigmine in action
• Has a brief duration of action (10–30 min)
• Diagnostic agent for myasthenia gravis
• Dose: 2–10 mg i.v.
27. Myasthenic vs Cholinergic crisis
• Myasthenic crisis Ach ↓↓
• Cholinergic crisis Ach ↑↑
• Edroph. (Rev. inhib. of AchE) ↑ Ach at NMJ
↓ ↓
Dramatic improvement Worsened condition
(Myasthenic crisis) (Cholinergic crisis)
• Short duration of action (desirable for pts.
presenting with cholinergic crisis as the worsening
in their condition would be for short lasting)
28. Uses of anti-cholinesterases
1. Glaucoma
2. To reverse the effect of mydriatic After
refraction error testing
3. To prevent and break adhesions between iris and
lens/cornea Miotic is altered with mydriatic
4. Myasthenia gravis Neostigmine is used
5. Postoperative decurarization To reverse effect
of muscle relaxants
6. Postoperative paralytic ileus/urinary retention
31. 7. Cobra bite To antagonize the curare-like action
of cobra neurotoxin
8. Belladonna poisoning Physostigmine is drug of
choice for atropine poisoning
9. Alzheimer’s disease Rivastigmine, Donepezil
and Galantamine afford some symptomatic
improvement
32. Signs and symptoms of OP
poisoning (Muscarinic)
M Miosis
U Urination
S Secretions↑ (Salivation, lacrimation & sweating)
C Cardiac contraction & conduction slows
A Abdominal cramps
R Reduction in i.o.t. (esp. in glaucoma)
I Increased GI motility
N NO (Nitric oxide) dependent vasodilatation
I Inc. sec. from GIT & tracheobronchial tract
C Constriction of tracheobronchial tract
35. Treatment
1. Termination of further exposure to the poison—
fresh air, wash the skin and mucous membranes
with soap and water, gastric lavage according to
need
2. Maintain patent airway, positive pressure
respiration if it is failing
3. Supportive measures—maintain BP, hydration,
control of convulsions with judicious use of
diazepam
36. Specific antidotes
1. Atropine All cases of anti-ChE (carbamate or
organophosphate) poisoning must be promptly
given atropine 2 mg i.v. repeated every 10 min till
dryness of mouth or other signs of atropinization
appear (upto 200 mg has been administered in a
day). Continued treatment with maintenance
doses may be required for 1–2 weeks
2. Cholinesterase reactivators Pralidoxime is
injected i.v. slowly in a dose of 1–2 g (children
20–40 mg/kg) [Only in OP poisoning]
39. Adverse effects of Atropine
(DHATURA)
1. Dry mouth, difficulty in swallowing & speaking
2. Hot dry skin & hypotension
3. Accommodation paralysis (blurring of near vision)
4. Tachycardia
5. Urinary Retention & fecal retention (constipation)
6. Ataxia & acute congestive glaucoma may
precipitate
• “Dry as a bone, blind as a bat, red as a beet, and
mad as a hatter”
40.
41. Dental implication of atropine
• Xerostomia caused by atropinic drugs can promote
dental caries and oral candidiasis
42.
43. Treatment of atropine poisoning
1. If poison has been ingested, gastric lavage should
be done with tannic acid
2. Patient should be kept in a dark quiet room
3. Cold sponging or ice bags are applied to reduce
body temperature
4. Physostigmine 1–3 mg s.c. or i.v. antagonises
both central and peripheral effects
5. Other general measures (maintenance of blood
volume, assisted respiration, diazepam to control
convulsions) should be taken as appropriate
44.
45. Contraindications of atropine
1. Individuals with a narrow iridocorneal angle—
may precipitate acute congestive glaucoma
2. Caution is advocated in elderly males with
prostatic hypertrophy—urinary retention can
occur
46. Interactions
1. Absorption of most drugs is slowed because
atropine delays gastric emptying. Extent of
digoxin and tetracycline absorption may be
increased
2. Antihistaminics, tricyclic antidepressants,
phenothiazines, disopyramide, pethidine have
anticholinergic property—additive side effects
occur with atropinic drugs
47. Uses of other anti-cholinergics
1. To relieve urinary frequency and urgency,
enuresis in children (Vasicoselective)
2. Bronchial asthma and COPD Ipratropium
bromide and Tiotropium bromide
3. Parkinsonism Central anticholinergics reduce
tremor and rigidity
4. Motion sickness Hyoscine (severe case),
Dicyclomine (mild cases)
Hinweis der Redaktion
involuntary ; A ganglion is a group of neuron cell bodies in the peripheral nervous system. In the somatic nervous system this includes dorsal root ganglia and trigeminal ganglia among a few others. In the autonomic nervous system there are both sympathetic and parasympathetic ganglia which contain the cell bodies of postganglionic sympathetic and parasympathetic neurons respectively.
The efferent neurons carry signals away from the brain and spinal cord to the peripheral tissues, and the afferent neurons bring information from the periphery to the CNS.
A ganglion is a collection of neuronal bodies found in the voluntary and autonomic branches of the peripheral nervous system (PNS).
Ganglia can be thought of as synaptic relay stations between neurons. The information enters the ganglia, excites the neuron in the ganglia and then exits.
"ganglion" should be reserved for collections of nerve cell bodies outside the central nervous system and nuclei should be used for collections of neurons inside.
While AChE is strategically located at all cholinergic sites and serves to inactivate ACh instantaneously, BuChE present in plasma and elsewhere probably serves to metabolize ingested esters.
Edrophonium is a short and rapid-acting anticholinesterase drug. Its effect is manifest within 30 to 60 seconds after injection and lasts an average of 10 minutes.
Deficiency of Ach in M. crisis
Paralytic ileus is the condition where the motor activity of the bowel is impaired, usually without the presence of a physical obstruction.
Why neostigmine & not physostigmine in myasthenia gravis ? m. Gravis A.b. against Nm rec.; 1. Neost. Has acn. On periph. Tissues without causing a/e in CNS;2. direct agonistic action on Nm rec. in addn. to inh. Of chE 3. Physost. Produces undesirable central effects. It lacks the direct agonistic action on nicotinic cholinergic receptors
Ptosis /ˈtoʊsɪs/ is a drooping or falling of the upper eyelid.
Cobra venom consists of a neurotoxin which is responsible for respiratory paralysis simulating that associated with a non-depolarizing muscle relaxant
a brief spontaneous contraction affecting a small number of muscle fibres, often causing a flicker of movement under the skin
A fasciculation, or muscle twitch, is a spontaneous, involuntary muscle contraction and relaxation, involving fine muscle fibers
The high affiity of pralidoxime for phosphorus enables it to break the phosphorus bond with cholinesterase and thereby regenerate the enzyme
Pralidoxime is ineffective as an antidote to carbamate anti-ChEs (physostigmine, neostigmine, carbaryl, propoxur) in which case the anionic site of the enzyme is not free to provide attachment to it.
Cycloplegia is paralysis of the ciliary muscle of the eye, resulting in a loss of accommodation
Inhaled mercury vapours while making hats
Delirium an acutely disturbed state of mind characterized by restlessness, illusions, and incoherence, occurring in intoxication, fever, and other disorders.
Why Physostigmine is preferred over Neostigmine in Atropine Poisoning ? P is tert. Amine (lipid soluble) & crosses BBB. Neost. Cannot cross BBB due to its polar nature & therefore, not able to reverse the central sympt. Of atr. poisoning