nervous system pharmacology Al Azhar University Gaza Dr. lama khaled El Banna Faculty of Oral and Dental Medicine

1. Nervous System
Dr. Mahmoud H. Taleb
Assistant Professor of Pharmacology and Toxicology
Head of Pharmacology and Medical sciences Department
Faculty of Pharmacy- Al azhar University

2. Central Nervous System (CNS) - Brain and
spinal cord
Peripheral Nervous System (PNS) - Located
outside the brain & spinal cord
* Autonomic Nervous System (ANS) &
the somatic
The PNS receives stimuli from the CNS &
initiates responses to the stimuli after it’s
interpreted by the brain

3. General organization of NSGeneral organization of NS
1.1. Central Nervous SystemCentral Nervous System
► The brain + the spinal cordThe brain + the spinal cord
• The center of integration and controlThe center of integration and control
1.1. Peripheral Nervous SystemPeripheral Nervous System
► The nervous system outside of the brain andThe nervous system outside of the brain and
spinal cordspinal cord
► Consists of:Consists of:
• 31 Spinal nerves31 Spinal nerves
► Carry info to and from the spinal cordCarry info to and from the spinal cord
• 12 Cranial nerves12 Cranial nerves
► Carry info to and from the brainCarry info to and from the brain
Dr. Mahmoud H. 3

4. ► Responsible for communication btwn theResponsible for communication btwn the
CNS and the rest of the body.CNS and the rest of the body.
► Can be divided into:Can be divided into:
• Sensory DivisionSensory Division
►Afferent divisionAfferent division
• Conducts impulses from receptors to the CNSConducts impulses from receptors to the CNS
• Informs the CNS of the state of the body interior and exteriorInforms the CNS of the state of the body interior and exterior
• Sensory nerve fibers can beSensory nerve fibers can be somaticsomatic (from skin, skeletal(from skin, skeletal
muscles or joints) ormuscles or joints) or visceralvisceral (from organs w/i the ventral(from organs w/i the ventral
body cavity)body cavity)
• Motor DivisionMotor Division
►Efferent divisionEfferent division
• Conducts impulses from CNS to effectors (muscles/glands)Conducts impulses from CNS to effectors (muscles/glands)
• Motor nerve fibersMotor nerve fibers
Dr. Mahmoud H. 4
Peripheral Nervous System

5. Motor Efferent DivisionMotor Efferent Division
► Can be divided further:Can be divided further:
• Somatic nervous systemSomatic nervous system
►VOLUNTARY (generally)VOLUNTARY (generally)
►Somatic nerve fibers that conduct impulses fromSomatic nerve fibers that conduct impulses from
the CNS to skeletal musclesthe CNS to skeletal muscles
• Autonomic nervous systemAutonomic nervous system
►INVOLUNTARY (generally)INVOLUNTARY (generally)
►Conducts impulses from the CNS to smoothConducts impulses from the CNS to smooth
muscle, cardiac muscle, and glands.muscle, cardiac muscle, and glands.
5

6. Autonomic Nervous SystemAutonomic Nervous System
Can be divided into:Can be divided into:
• Sympathetic NervousSympathetic Nervous SystemSystem
• ““Fight or Flight”Fight or Flight”
• ParasympatheticNervousParasympatheticNervous
SystemSystem
• ““Rest and Digest”Rest and Digest”
6
These 2 systems are antagonistic.These 2 systems are antagonistic.
Typically, we balance these 2 to keepTypically, we balance these 2 to keep
ourselves in a state of dynamic balance.ourselves in a state of dynamic balance.

7. Divisions of human nervous systemDivisions of human nervous system
7Dr. Mahmoud H. Taleb

8. Nervous systemNervous system
8Dr. Mahmoud H. Taleb

9. Summary of some neurotransmitters of the central nervousSummary of some neurotransmitters of the central nervous
system. GABA = λ-aminobutyric acidsystem. GABA = λ-aminobutyric acid
Dr. Mahmoud H. 9

11. Parasympathetic ResponsesParasympathetic Responses
11Dr. Mahmoud H. Taleb

12. Dr. Mahmoud H. Taleb 12

13. Is the neurotransmitter of the parasympatheticIs the neurotransmitter of the parasympathetic
N.S and cholinergic nerves, it is therapeuticallyN.S and cholinergic nerves, it is therapeutically
of no importance due to:of no importance due to:
1. Multiplicity of actions.1. Multiplicity of actions.
2. Rapid inactivation by acetyl-cholinesterase.2. Rapid inactivation by acetyl-cholinesterase.
3. Has both muscarinic and nicotinic activity.3. Has both muscarinic and nicotinic activity.
ACHACH
Dr. Mahmoud H. Taleb 13

14. Dr. Mahmoud H. Taleb 14

15. ““SLUDGE”SLUDGE”
SSalivationalivation
LLacrimationacrimation
UUrinary incontinencerinary incontinence
DDiarrheaiarrhea
GGastrointestinal crampsastrointestinal cramps
EEmesismesis
Drug Effects of Cholinergic AgentsDrug Effects of Cholinergic Agents
15Dr. Mahmoud H. Taleb

16. Figure 20-2.
Sympathetic and Parasympathetic Effects on Body Tissues

17. Dr. Mahmoud H. Taleb 17

18. ANS - Sympathetic nervousANS - Sympathetic nervous
system (Adrenergic)system (Adrenergic)
Sympathetic Nervous System (adrenergic)
Norepinephrine = neurotransmitter
- Drugs that mimic = adrenergic drugs,
sympathomimetics, or adrenomemetics
* Adrenergic agonists - Drugs initiate a
response
- Drugs that block = adrenergic blockers,
sympatholytics or adrenolytics
* Adrenergic antagonists - prevent a response

19. 19

20. SYMPATHETIC RESPONSESSYMPATHETIC RESPONSES
20Dr. Mahmoud H. Taleb

21. Dr. Mahmoud H. Taleb 21

23. Neurotransmission in adrenergic neurons closelyNeurotransmission in adrenergic neurons closely
resembles that already described for the cholinergicresembles that already described for the cholinergic
neurons except that norepinephrine is theneurons except that norepinephrine is the
neurotransmitter instead of acetylcholine.neurotransmitter instead of acetylcholine.
Neurotransmission takes place at numerous bead-likeNeurotransmission takes place at numerous bead-like
enlargements called varicosities. The process involvesenlargements called varicosities. The process involves
five steps:synthesis, storage, release, and receptorfive steps:synthesis, storage, release, and receptor
binding of norepinephrine, followed by removal of thebinding of norepinephrine, followed by removal of the
neurotransmitter from the synaptic gapneurotransmitter from the synaptic gap
A. NeurotrANsmissioN AtA. NeurotrANsmissioN At
AdreNergic NeuroNsAdreNergic NeuroNs
Dr. Mahmoud H. Taleb 23

24. : Adrenergics and Adrenergic: Adrenergics and Adrenergic
BlockersBlockers
Drugs that Stimulate the sympathetic Nervous
System (adrenergics, adrenergic agonists,
sypathomimetics, or adrenomimetics)
Mimic the sympathetic neruotransmitters
norepinephrine and epinephrine
Act on one or more adrenergic receptor sites
located on the cells of smooth muscles -
heart, bronchioles, GI tract, bladder, eye
4 main receptors (alpha-1, alpha-2, beta-1,
beta-2)

25. SYMPATHETIC RESPONSESSYMPATHETIC RESPONSES

26. Sympathomimetics/Sympathomimetics/
AdrenomimeticsAdrenomimetics
Stimulate adrenergic receptors: 3 categories
1. Direct-acting = directly stimulates receptors
(epinephrine or norepinephrine)
2. Indirect-acting = stimulates release of norep.
from terminal nerve endings (amphetamine)
3. Mixed-acting (indirect & direct) = stimulates
receptor sites & release of norep. from nerve
endings (Ephedrine)

27. Sympathomimetic Agents/Sympathomimetic Agents/
AdrenergicsAdrenergics
Action - Many of the adrenergic drugs
stimulate more than one of the adrenergic
receptor sites (alpha & Beta)
Response = Inc. BP, pupil dilation, inc. HR, &
bronchodilation
Use = Cardiac stimulation, bronchodilator,
decongestant
Side effects = Hyperness in body

28. Sympathomimetics/AdrenergicsSympathomimetics/Adrenergics
Albuterol - Beta-2 agonist (bronchodilation)
Use - bronchospasm, asthma, bronchitis
SE - nervousness, restlessness
CI - severe cardiac disease, HTN
Epinephrine - stimulates alpha & beta
Use - allergic reaction, cardiac arrest
SE - nervousness, agitation
CI - cardiac dysrhythmias

29. Adrenergic AgentsAdrenergic Agents
Dopamine - alpha-1 & beta-1
stimulation
Use - Hypotension, shock, inc. cardiac
output, improve perfusion to vital
organs
SE - N & V, headache
CI - V. Tach

30. Adrenergic BlockersAdrenergic Blockers
(antagonists/sympatholytics)(antagonists/sympatholytics)
Block alpha & beta receptor sites
(nonselective)
direct or indirect acting on the release of
norepinephrine and epinephrine
Use - Cardiac arrthymias (HR), HTN ( cardiac
output), angina (O2 demand)
SE - CHF, bronchospasm, bradycardia,
wheezing

31. Nonselective vs Selective BetaNonselective vs Selective Beta
blockersblockers
Nonselective have an equal inhibitory effect
on B1 & B2 receptors -
- Drugs have lots of interactions due to lots of
alpha/beta receptor sites throughout body
- use with caution on clients with cardiac
failure or asthma
Selective B1 helpful in asthma clients

32. Adrenergic Blocking AgentsAdrenergic Blocking Agents
Inderal (Propranolol) - Nonselective
Use - angina, dysrhythmias, HTN, migraines
SE - Many d/t nonselective
CI - asthma, heart block > 1st degree
Minipress (Prazosin) - A blocker
Use - mild to mod. HTN
SE - orthostatic hypotension
Tenormin (Atenolol), Lopressor (Metoprolol)
B1 (cardio) selective
Use - mild to mod HTN, angina

33. Cholinergics andCholinergics and
AnticholinergicsAnticholinergics
Cholinergics stimulate the parasympathetic
nervous system
Mimic the neurotransmitter acetylcholine
2 types of cholinergic receptors
1. muscarinic - stimulates smooth muscle &
slows HR
2. nicotinic - affect skeletal muscle
Many = nonselective & affect both receptors
Some affect only the muscarinic receptors
and not the nicotinic receptors

34. Parasympathetic ResponsesParasympathetic Responses

35. Cholinergic AgentsCholinergic Agents
Direct acting - act on the receptors to
activate a tissue response
Indirect acting - inhibit the action of the
enzyme cholinesterase
(acetylcholinesterase - ACH)
Major uses = Stimulate bladder & GI
tone, constrict pupils (miosis), neuro-
muscular transmission

36. Direct-acting ParasympathomimeticDirect-acting Parasympathomimetic
(cholinergic drugs)(cholinergic drugs)

37. Cholinergic AgentCholinergic Agent
(Parasympathomimetics)(Parasympathomimetics)
Bethanechol (Urecholine) selective to
muscarinic receptors, mimic action of
acetylcholine
Use - For urinary retention
* Take on an empty stomach d/t inc. peristalsis
* Alert- Never give IM or IV – circulatory
collapse, hypotension, shock & cardiac arrest
poss.
Pilocarpine (Pilocar) - Ophthalmic - direct
acting

38. Cholinergic Blocking AgentsCholinergic Blocking Agents
Anticholinergics/ParasympatholyticsAnticholinergics/Parasympatholytics
Drugs that inhibit action of acetylcholine
(ACH) receptors
Affects the heart, resp. tract, GI tract, bladder,
eye, & exocrine glands.
Allows the sympathetic nervous system to
dominate
Anticholinergic & cholinergic drugs have
opposite effects
Major responses = dec. in GI motility, dec. in
salivation, dilation of pupil (mydriasis), inc.
pulse rate

39. AnticholinergicsAnticholinergics
Uses: Pre-op meds,bradycardia, GI/urinary
antispasmodic
SE: Dry mouth/mucus membranes
Atropine Sulfate - Inhibits ACH blocks
vagal effects on SA & AV nodes inc.
conduction & inc. HR
Use = Bradycardia, pre-up to dec. secretions,
peptic ulcer disease
SE = Many. Most frequent = dry mouth,
blurred vision, urine retention, constipation

40. AnticholinergicsAnticholinergics
(Dicyclomine) - Inhibits ACH on muscarinic
receptors & dec. GI motility
Use - Irritable bowel syndrome
SE - constipation, urinary retention, dry mouth

41. AnticholinergicsAnticholinergics
Anticholinergics effect the CNS & benefit
people prone to motion sickness
Scopolamine Patch - Classified as an
antihistamine for motion sickness