Autonomic nervous system

1. Yousaf khan
Renal Dialysis Lecturer
IPMS-KMU

2. CNS- Bain and spinal cord
Peripheral- Nervous outside brain- enter or leave ( afferent and
efferent = reflex arc = neural pathway
• Somatic and ANS (vital body function – smooth muscle cardiac
muscle, blood vessels and exocrine gland
ANS:
• Efferent ( preganglionic – cell body – CNS, Postganglionic – cell
body – ganglion – non myelinated and terminate on effector organ
• Afferent – reflex regulation e.g baroreceptor

3. Sympathetic system
• thoracolumber region (T1 to L3)
• preganglionic fiber short and
postganglionic long
• Sweat gland, hair follicles,
spleen and most of the blood
vessals
Parasympathetic system
• cranial outflow – cranial nerves
III(oculomotor) , VII (facial),
IX(glossopheryngeal), X(vegus)
• sacral outflow from S2, S3 and
S4 Spinal Roots
• preganglionic fiber are very
long and postganglionic very
short
• Ciliary muscle, pancreatic and
gastric glands
Most of the visceral organ have dual
nerve supply i.e

4. • Ach is the neurotransmitter in the cholinergic system
• cholinergic neurons involves six sequential
• 1) synthesis,
• 2) storage
• 3) release
• 4) binding of ACh to a receptor
• 5) degradation of the neurotransmitter in the synaptic cleft
• 6) recycling of choline and acetate

5. True cholinesterase or ACHE:
• it found in cholinergic neuron, ganglia, RBCs and neuromuscular
junction,
• It rapidly hydrolyses Ach and methacholine
Pseudocholinesterase:
• its found in plasma, liver and glial cell
• Can act a wide veriety esters including Ach but does not hydrolyse
methacholine

6. Muscarinic receptor
• M1 – gastric gland, autonomic ganglia, CNS
• M2- Heart
• M3- Smooth muscles, exocrine glands, Endothelial cells
• M4, M5- CNS
• All muscarinic receptor are G-protein coupled receptor regulate the
production of intracellular second messengers.
Nicotinic receptor
• Nn – autonomic ganglia, adrenal medulla
• Nm- neuromuscular junction
• Activation of these receptor directly open the ion channels and cause
depolarization of the membrane

7. Cholinergic agonist:
Directly acting
Choline ester
• Acetylcholine
• Bathanechol
• carbachol
Alkaloids
• Pilocarpine
• muscarine
Indirectly acting
Indirectly acting
(anticholinesterases)
Reversible
Carbamates
• Neostigmine
• Donepezil
• Rivastigmine
• Edrophonium
Irreversible
Organophospho
us compound
(OP)
• Parathion
• Malathion
• Sarin,
• soman
• dyflos

8. • These drug active the cholinergic receptor by directly binding to
them. Their action depend on whether they stimulate muscarinic or
nicotinic receptor.
• Acetylcholine:
• Acetycholine is not used therapeutically because its duration of
action is very brief ( a few milisecond) because it is rapidly
inactivated by a specific enzyme acetycholinerstrase.
• Muscarinic action:
A: cardiovascular system:
• Heart rate is decreased ( -ve chrontropic effect)
• Force of contraction is decrease (-ve iontropic effect)
• Decrease A.V conduction ( -ve dromotropic effect – decrease b.p)

9. B: blood vessels:
• Vasodilation – decrease b.p
C: Smooth muscles:
A: Gastrointestinal tract:
• Tone and motility are increase
• Gastric and salivary secretion are increased
• Sphincters are relaxed
B: Urinary tract:
• Contraction of detrusor muscle and relaxation of internal urethral
sphincter result in emptying of urinary bladder

10. C: Respiratory system:
• Bronchial constriction and increase bronchial secretion
Eye:
• Stimulation of the constrictor pupillary muscle resulting in miosis
• Contraction of ciliary muscle resulting in spasm and accommodation
for near vision
Exocrine glands:
• Salivary, lacrimal, gastric, pancreatic, intestinal, nasopharyngeal and
bronchial secretion are stimulated

11. NICOTINIC ACTION:
CVS:
• Stimulation of sympathetic ganglia and adrenal medulla, with
discharge of adrenaline and noradrenaline, resulting in
vasconstriction, techycardia and increase blood pressure
• CNS:
• Stimulation of CNS ( alertness, tremors, convulsion) followed by
depression
• Release of ADH
ANS:
• Initially stimulation of autonomic ganglia leading to activation of both
sympathetic and parasympathetic system. Subsequently
depolarizing type of paralysis of all autonomic ganglia.

12. Neuromuscular junction:
• Depolarization of the neuromuscular junction resulting in muscle
contraction, followed by depolarization type of neuromuscular
blocked.
GIT:
• Tone and peristalsis are increased
Glands:
• Stimulation of salivary and bronchial secretion
Side- Effect of cholinergic agonist:
• Nausea, vomiting, increased salivation, diarrhea, bronchospasm and
abdominal cramps

13. Action:
• It is not inactivated by acetylcholinertrase but by other esterases
unlike Ach that is inactivated by acetylchlinestrase
• It has strong muscarinic activity and has no nicotinic action
• It is major action on the smooth muscles of urinary bladder and GIT
causing
• increase intestinal motility
• Stimulate detrusor muscles of bladder while the trigon and sphincter
are relaxed, causing expulsion of urine
• Duration of action Is 1 hr

14. Therapeutic uses:
• It is used to atonic bladder, particularly in postpartum or
postoperative urinary retension.
• Post operative abdominal distension
• In reflux esophagitis it is used to increase lower esophageal
sphincter tone
Side effect:
• Sweating, salivation, flushing, hypotension, nausea, abdominal pain,
diarrhea and bronchospasm
Contraindication:
• Asthma, hyperthyroidism, coronary insufficiency and peptic ulcer