THE AUTONOMIC NERVOUS SYSTEM · CRANIO-SACRAL DIVISION ... Autonomic neural control mechanisms. With special reference to the ... Visceral afferents e.g. vasomotor (RVLM),

AUTONOMIC NERVOUS SYSTEM

THE AUTONOMIC NERVOUS SYSTEM

Judit Rosta

TOPICS Nr. 19-20.

9/19/2018 Evening Seminar Notes-Phys


…“I propose the term 'autonomic' nervous

system for the sympathetic system and the

allied nervous system of the cranial and

sacral nerves and for the local nervous

system of the gut .”…

(John Newport Langley, 1898)



Autonomic Peripheral

Efferents

maintain cardiovascular, gastrointestinal

and thermal homeostasis

and organization of stress responses

Autonomic(„automatic control”)

Vegetative(function)


„ …System of motor nerve cells

to ‚involuntary’ structures”: (Gaskell, 1916)



Menitmeter


• source of innervation (sympathetic-parasymp.,dual-not dual)

• the activity of the nerves (tonic or phasic)

• the effect of nervous activation (contraction-relaxation,

stimulating/inhibiting secretion, +/- cardiac effects etc.)

• neurotransmitter using which receptor (muscarinic cholinergic, alpha

(1 or 2) or beta (1, 2 or 3) adrenergic, perhaps „NANC” mechanism)

• peripheral or central nervous structures control nervous activity-

vegetative reflexes

Autonomic control of a target organ:

(smooth muscle, cardiac muscle, glands)



„ ‚Sympathy’ ?: as cooperation and coordination of organs”

SY

PARASY

PARASY

AND THE ‚PARA’SYMPATHETIC :

CRANIO-SACRAL DIVISION

(flank on both sides)

„each tissue supplied by two sets of fibers with

opposite characters”

Dual innervation-Antagonistic effects

THE SYMPATHETIC TRUNK:

PARAVERTEBRAL CHAIN

Thoracolumbar origin



SYMPATHETIC

PARASYMPATHETIC


NOTICE ! Structure (location of ganglia)Fiber type (myelinization)Neurotransmitters (Ach, NE,E)



Menitmeter

How does look like the autonomic innervation?Choose the typical presynaptic arrangement of an autonomic neuron!

Common presynaptic arrangements:



Burnstock (1988) Autonomic neural control mechanisms. With special reference to the airways. In: Kaliner, M.A., Barnes, P.J. (Eds.)

How does look like the autonomic innervation?

Network of varicose terminal axons containing norepinephrine in iris

((Falck, 1962)

VARICOSITY: contain the enzymes necessary to synthesize or degradetransmitters

Autonomic ground plexus

cotransmitters: Ach+ATP, Norepinephrine+NPY(act on their own receptors!)


Cotransmitter: Ach + VIP, NO

Botulinum TOXIN

Physostigmin

ACETYLCHOLINE

Parasympathetic(and sudomotor sympathetic)

Notice!

Acetylcholinesterase (AchE)

Choline reuptake

Botulinum toxin blocking

AchE blocking-muscarinic

Atropine-antimuscarinic

ATROPINE


Cotransmitter: NE + NPY, ATP

NOTICE!

Synthetisation-vesicles

NE-terminals, E-adrenal med.

Metabolism by: COMT, MAO

Neuronal reuptake

Autoreceptor

blocked by cocaine !

CATECHOLAMINES



Adrenaline (Epinephrine) is far more potent beta-adrenoceptor agonistthan NA. Importance of circulating A in arrythmias and bronchi

+-

At low concentration of Adrenaline b2 effect

predominates vasodilation (anticipation)

At high plasma concentration of Adrenaline

a1 effect predominates vasoconstriction

SKELETAL MUSCLE ! BLOOD VESSELS

RECEPTORS

M1,2,3

LUNG

HEART

b2



AUTONOMIC PHARMACOLOGY

-MIMETICS (+):

1. increase synthesis/release of NT

2. decrease degradation of NT

3. use receptor agonist

4. block synthesis of NT

5. block release of NT

6. use receptor antagonist

-LYTICS:

Antimuscarinic effect: M-AchRantagonist (Atropine)

Sympathomimetic e.g.: Amphetamineincreases NE synthesis and release

AUTONOMIC NERVOUS SYSTEM CURARE (-)

nAchR

ATROPINE

M-AchR

E: b>a

PROPRANOLOL (-)

a-AR

BOTULINUM TOXIN (-)

9/19/2018

PRAZOSIN (-)

COCAINE(+)

NICOTINE

nAchR

AU

TO

NO

MIC

PH

AR

MA

CO

LOG

Y

ISOPROTERENOL (+)

b-AR

AMPHETAMINE (+)

PHYSOSTIGMINE(AchE inhibitor)

nAchR

nAchR

nAchR



constricts sphincters

Release of glucagonGlucose levels up


Evening Seminar Notes-Phys

tonic activity of the autonomic nervous

system under resting condition

VEGETATIVE TONE

- psy tone in the heart

- sy tone in the arterioles

- psy tone in the bronchi

Predominance of a

division!

at rest increased effectdecreased effect

Pattern of action potentials rate of an autonomic fiber exerts tonic activity

return individually below


How can we distuinguish between sympathetic and parasympathetic autonomic nerves? (1)

a) Functionally, based on whether the effects can be attributed to the to „rest and digest” or the „flightor fight” group of responses

b) Neurochemically, as the sympathetic nerves are all adrenergic and the parasympathetic nerves are all cholinergic

c) Anatomically, as the sympathetic nerves stem from the thoracolumbal spinal cord segments, and the parasympathetics stem from the brainstem as well as from the sacral spinal cord segments


Mentimeter



Mentimeter

Choose, which of the followings can be used stimulate

the urinary bladder following surgery:

1. M-AchR agonist MUSCARINE

2. 2.M-AchR- antagonist Atropine

3. 3. sympathomimetics like MAO inhibitors

AUTONOMIC NERVOUS SYSTEMCASE STUDY ANALYSIS


Case:

Antecedent: 10-years old boy, „red face”, disoriented, distracted

manner, hot temperature

Basic parameters: blood pressure 170/110 Hgmm,

pulse 144/min !

temperature 39.6 !

Flushed, hot, dry skin

Dilated pupils! (mydriasis), cycloplegia (no accomodation)

Neurological symptoms: amnesia, hallucination



CASE STUDY ANALYSIS

SY provocation and/or Psy dropout ??

SYMPTOMS COMMENT

CONSIDER!

-Compare heart effects and vasoactive effects

-Source of ciliary muscles innervation (accomodation reflex)

-Sudomotor effects (dry skin)

dilated pupils


Symptoms Comment:

BP:170/110 Hgmm little effect on blood pressure (not so much muscarinergic

vasodilation what can be suspended)

HR: 144/min speeds up the heart rate and increases conduction velocity= PSY

tone decreased

Flushed, hot, dry

skin

inhibited the activity of sweat glands

T: 39.6 sweating sufficiently depressed and this elevated the body

temperature

Dilated pupils

(mydriasis)

cholinergically innervated sphincter muscles of the iris relaxed

Cycloplegia

(no accomodation)

accommodative ciliary muscle of the lens is blocked

Amnesia,

Hallucinationrestlessness

symptoms can be explained by loss of muscarinic effects9/19/2018 Evening Seminar Notes-Phys

CASE STUDY ANALYSIS


Diagnosis: Atropine Overdose

ANTIMUSCARINIC INTOXICATION

Course: Small doses of Physostigmine slowly intravenously

administered

Within 6 hours normal vital signs. The remainder of the

stay was uneventful.


Case History: Ingestion of black

seeds of a plant

located near the house

CASE STUDY ANALYSIS


pinterest.com

Physostigmine has side effects on skeletal muscles (Ach up)


Atropine effect: M-AchR antagonist

Course: PSY mimetic (Physostigmine)

Overdose: ANTIMUSCARINIC INTOXICATION

ATROPINE


Atropine and Antimuscarinic Alkaloids:


• Atropa Belladonna: medicine, cosmetic and poison

the devil’ breath aka SCOPALAMINE- an alkaloid of belladonna, is helpful in treating motion sickness

Belladonna has a long history of medicinal applications in healthcare

Scopalamine: „…criminals in Colombia and Ecuador use the

drug, which is said to remove a person’s free will…”

(TheGuardian)

The famous poison

of Roman

Emperors’ wives

• Datura stramonium: hallucinogen- fatally toxic

Extracurrical


More adverse effect

Gastrointestinal tract decreased bowel sounds, reduction of salivary secretion

Respiratory tract inhibits the secretion of nose, mouth, pharynx and

bronchi

produces bronchodilation

Urinary retention Urinary sphincter contraction

Therapeutic Uses of Atropine

PREANAESTHETIC MEDICATION Can suppress bronchiolar secretions and reduce the risk

of airway obstruction

increase the heart beat when anaesthetic drug is going

to be used

ANTIDIARRHEAL DRUG in the treatment of irritable bowel movement

OPTHALMOLOGICAL USES; against peptic ulcer; dries up breast milk…

Extracurrical


ATROPINE


Exemptions of Dual Innervation

adrenal medulla

arrector pili muscles

sweat glands

most blood vessels

musc.dilatator pupillae

ventricle of the heart

lacrimal gland acini

ciliary muscle

musc. sphincter pupillae

Bronchial smooth muscle


PSYSY



HEART

The endogenous frequency of the pacemaker cells: 100 AP/min

The individual variation of the heart rate at rest is based mainly on the difference in the psy tone at rest

chronotropic effect:(incerased frequency of AP generation)

dromotropic effect:(increased speed of AP propagation)

heart rate: 72 beats/min!!!!!!Psy tone

+

+-

-

Predominance of PSY


INNERVATION OF THE PUPIL

T1

Nucl.Edinger-

Westphal

(oculomotor nucl.)

NOTICE!

Pupillary Light Reflex

(PSY REFLEX!)

ATROPINE

PSY: myosisSY: mydriasis


SY

PSY

The two distinctmuscles


Horner’s syndrome

„The loss of sympathetic”

Lesion of the superior cervical ganglion (tumor, trauma).Sympthoms: Horner’s (triad)- ipsilateral

Lost innervation of:1. Miosis - pipullary dilator muscle2. Ptosis - tarsalis muscle3. Enopthalmus - orbitalis muscle4. (Anhydrosis) - facial sweat glands5. (Flush) - facial skin arterioles

Pancoast tumor



Sympathetic VASOMOTOR TONE

Serum Ach caused endothelium-derived NO-

dependent relaxation

keeps vasculatura and arterioles partially

constricted and this maintains blood pressure

(regulating amount of blood flow into the

capillaries)

carry out their function through the change of their diameters

a1

BLOOD VESSELS WITHOUT DUAL INNERVATION


Bronchi

PSY

Vagal nerve

Bronchoconstriction, secretion (M1)

SY

Bronchodilation, secretion↓ (β2)

- Circulating EPINEPHRINE

parasympatheticpreganglionar

sympatheticpostganglionar

blood-stream

smoothmuscle

mucus secretion

contractiondilation

secretorygland

The bronchi don’t have sympathetic innervation but adrenergic receptors are

present which are activated by the circulating catecholamines.


Parasympathetic BRONCHOMOTOR Tone



increased smooth muscle contraction (bronchoconstrion)

increased smooth muscle contraction (bronchoconstrion)

mucosawall of the bronchus

lumensmooth muscle

increased secretion of the glands in the

airways

THERAPY: Dilatation of the airways

increase of the sympathetic effect decrease of the parasympathetic effect

b2-agonist Atropin

Bronchodilatation

direct smooth muscle relaxation Anticholinergic effect

Respir Res. 2006; 7(1): 73.

Bronchial asthma:

chronic inflammation of the airway


NICOTINE


Notice!

• Nicotine stimulates the postganglionic

neurons of both the sympathetic and

parasympathetic divisions!

• The action of nicotine on acetylcholine

receptors of the neuromuscular synapse is

much less important than that on ganglia of

the autonomic nervous system

• Different effects according to doses

(Agonist/Antgonist)

Nicotine lethal dose: 500-

1000 mg

Nicotine dosage in a traditional

cigarette: 2 mg

it would take smoking over 100

cigarettes in a short time period

to ingest a lethal dose

BUT: tobacco leaves through

skin can produce high doses



Vegetative Functions: Integrative Function of the Spinal Cord

Micturition Reflex

• spinal reflexes: – erection

– defecation

– urination

The ‚VEGETATIVE REFLEX’



Vegetative Functions:Supraspinal Stimuli- Brainstem control

• brainstem reflexes:e.g. touching cornea – lacrimation; salivation, swallowing, vomiting, coughing, sneezing

HYPOTHALAMUS

Thermoregulation:

Preoptic area

Peripheral thermoreceptors

Sympathetic vasomotor, sudomotor

Endocrine response: TRH,tiroxin synthesis

MEDULLA

Nucl. Tractus Solitarii

Vegetative efferents

Visceral afferents

e.g. vasomotor (RVLM), respiratory, coughing centre interneurons

Target organ



Anticipation of exercise

Heart rate, blood pressure and respiratory

rate increased with anticipation

Vegetative stimulation correlates with activation

in certain structures in CNS

(etc. PAG, dorsal raphe nuclei) Limbic system, cortical areas

Vegetative Functions:Supraspinal Stimuli- Central Coordination

Spinal shock-areflexia- loss of central

excitatory impulses

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THE AUTONOMIC NERVOUS SYSTEM · CRANIO-SACRAL DIVISION ... Autonomic neural control mechanisms. With special reference to the ... Visceral afferents e.g. vasomotor (RVLM),