PHL. 322PHL. 322Presented byPresented by

Dr. Khairy M A ZoheirDr. Khairy M A ZoheirAssociate ProfessorAssociate Professor

College of PharmacyCollege of PharmacyKSUKSU

I- CNS Stimulants I- CNS Stimulants DrugsDrugs  

Nervous SystemNervous System    

• The nervous system can be classified The nervous system can be classified intointo

• The Central Nervous System The Central Nervous System ((CNS)CNS) Brain and spinal cord Brain and spinal cord

• The Peripheral Nervous System The Peripheral Nervous System ((PNSPNS(( The nervous system outside of The nervous system outside of the brain and spinal cordthe brain and spinal cord  

Peripheral Nervous  System  Peripheral Nervous  System  PNSPNS  

  

Can be divided intoCan be divided into - -11 - -Sensory divisionSensory division((affrent)affrent)

Conducts impulses from receptors to the Conducts impulses from receptors to the CNS and Informs the CNS of the state of CNS and Informs the CNS of the state of the bodythe body 2- 2- Motor divisionMotor division((effrent)effrent)Conducts impulses from CNS to effectors Conducts impulses from CNS to effectors

organsorgans..

Motor NeuronsMotor Neurons• The motor division is also divided intoThe motor division is also divided into• 1- 1- The somatic nervous system :The somatic nervous system :

•VOLUNTARY (generally) Somatic nerve VOLUNTARY (generally) Somatic nerve fibers that conduct impulses from the CNS fibers that conduct impulses from the CNS to skeletal musclesto skeletal muscles• 2. 2. The autonomic nervous system:The autonomic nervous system: INVOLUNTARY INVOLUNTARY ((generallygenerally)) Conducts Conducts

impulses from the CNS to smooth muscle, impulses from the CNS to smooth muscle, cardiac muscle, and glands cardiac muscle, and glands 

Neurons Neurons   

• They are the basic functional unit of They are the basic functional unit of the nervous systemthe nervous system..

• They contain three major partsThey contain three major parts::  • 1.cell body.1.cell body.• 2. dendrites.2. dendrites.• 3. axon.   3. axon.  

StructureStructure

Neurotransmitters CNSNeurotransmitters CNS    • They can be classified into They can be classified into ::  • 1. 1. Exitatory:Exitatory:• - Ach, glutamate, aspartate , - Ach, glutamate, aspartate ,

serotonin and NE. serotonin and NE. • 22. Inhibitory:-. Inhibitory:-• - GABA , glycin .- GABA , glycin .

CNS StimulantsCNS Stimulants  

• DefinationDefination““Stimulants are a substance Stimulants are a substance

which tends to increase which tends to increase behavioral activity when behavioral activity when administered”administered”

• Signs and symptoms:Signs and symptoms:• 1- Elevate Mood1- Elevate Mood• 2- Increase Motor Activity2- Increase Motor Activity• 3- Increase Alertness3- Increase Alertness• 4- Decrease need for Sleep4- Decrease need for Sleep• In case of overdose lead to In case of overdose lead to

convulsion and death.convulsion and death.

MOA of CNS StimulantsMOA of CNS Stimulants    •     1- Block neurotransmitters reuptake  1- Block neurotransmitters reuptake 

(Most reuptake inhibitors affect either NE (Most reuptake inhibitors affect either NE or 5-HT(Serotonin) : Cocaineor 5-HT(Serotonin) : Cocaine

• 2- Promote neurotransmitters release : 2- Promote neurotransmitters release : AmphetamineAmphetamine

• 3- Block Metabolism - MAO inhibitors 3- Block Metabolism - MAO inhibitors (monoamine oxidase):ex. Phenelzine (monoamine oxidase):ex. Phenelzine

• 4. antagonize the effect of inhibitory 4. antagonize the effect of inhibitory neurotransmitter: neurotransmitter: PicrotoxinPicrotoxin & & StrychnineStrychnine

•

Neuronal Synapse Neuronal Synapse

Neuronal SynapseNeuronal Synapse

CNS StimulantsCNS Stimulants    • - - They can be divided based on their site They can be divided based on their site

of actionof action::  

•         1.Cerebral stimulants (amphetamines) 1.Cerebral stimulants (amphetamines) 

•         2.Medullary stimulants (picrotoxin) 2.Medullary stimulants (picrotoxin) 

•         3.Spinal stimulants (strychnine)3.Spinal stimulants (strychnine)

Lab WorkLab Work  

• - - Objectives:Objectives:  • 1- To demonstrate effects of some CNS 1- To demonstrate effects of some CNS

stimulant on mice.stimulant on mice.• 2- After the lab, you should able to handle 2- After the lab, you should able to handle

and inject the mice correctly. and inject the mice correctly. • 3- You should able to differentiate 3- You should able to differentiate

between amphetamine,picrotoxin and between amphetamine,picrotoxin and strychinine regarding the symptoms that strychinine regarding the symptoms that induced by each of them.    induced by each of them.    

1- Amphetamine 1- Amphetamine 

• MOAs MOAs ::•       Block the reuptake of norepinephrine and Block the reuptake of norepinephrine and

dopamine into the presynaptic neuron and dopamine into the presynaptic neuron and increase the release of these monoamines increase the release of these monoamines into the extraneuronal space.  into the extraneuronal space.  - Clinical use:- Clinical use:

• 1. Narcolepsy.1. Narcolepsy.• 2. Attention-deficit hyperactivity disorder2. Attention-deficit hyperactivity disorder

AmphetamineAmphetamine  

• Adverse effectsAdverse effects::• - Cardiovascular: - Cardiovascular: Hypertension (7% to 22%, Hypertension (7% to 22%,

pediatric ) pediatric ) • - Endocrine metabolic: - Endocrine metabolic: Weight loss (4% to 9%, Weight loss (4% to 9%,

pediatric; 11%, adults ) pediatric; 11%, adults ) • - Gastrointestinal: - Gastrointestinal: Abdominal pain (11% to Abdominal pain (11% to

14%, pediatrics ), Loss of appetite (22% to 36%), 14%, pediatrics ), Loss of appetite (22% to 36%), Xerostomia (35% ) Xerostomia (35% )

• - Neurologic: - Neurologic: Headache (26% ), Insomnia Headache (26% ), Insomnia ارقارق ((1212% to 17%, pediatric; 27%, adults ) % to 17%, pediatric; 27%, adults )

• - Psychiatric: - Psychiatric: Feeling nervous (6% ) Feeling nervous (6% ) 

AmphetamineAmphetamine  

• After injecting,  the mice with After injecting,  the mice with amphetamine you well noticeamphetamine you well notice::  - Hair erection- Hair erection

• - Licking, gnawing.- Licking, gnawing.• - Stereotype- Stereotype• - Sniffing - Sniffing 

PicrotoxinPicrotoxin    

• MOAMOA::•     Non-competitive antagonist of GABA Non-competitive antagonist of GABA

receptors.receptors.• After injecting the mice with picrotoxin you After injecting the mice with picrotoxin you

well noticewell notice::  - - Clonic convulsionClonic convulsion characterized by :   characterized by :  

• 1. Asymmetric1. Asymmetric• 2. Intermittent2. Intermittent• 3. Spontaneous 3. Spontaneous • 4. Coordinated4. Coordinated

StrychinineStrychinine    

• MOAMOA::• Competitive antagonist of the glycin receptors. Competitive antagonist of the glycin receptors. 

• After injecting the mice with Strychinine you After injecting the mice with Strychinine you wellwell

• notice: notice: - - Tonic convulsionTonic convulsion characterized characterized by : by :

• 1. Symmetric 1. Symmetric • 2. Reflex in origin2. Reflex in origin• 3. Continuous 3. Continuous • 4. Uncoordinated.4. Uncoordinated.