PHL 322 Presented by Dr Khairy M A
PHL. 322 Presented by Dr. Khairy M A Zoheir
I- CNS Stimulants Drugs
Nervous System • The nervous system can be classified into • The Central Nervous System (CNS) Brain and spinal cord • The Peripheral Nervous System (PNS) The nervous system outside of the brain and spinal cord
Peripheral Nervous System PNS Can be divided into 1 - Sensory division(affrent) Conducts impulses from receptors to the CNS and Informs the CNS of the state of the body 2 - Motor division(effrent) Conducts impulses from CNS to effectors organs.
Motor Neurons • The motor division is also divided into • 1 - The somatic nervous system : VOLUNTARY (generally) Somatic nerve fibers • that conduct impulses from the CNS to skeletal muscles • 2. The autonomic nervous system: INVOLUNTARY (generally) Conducts impulses from the CNS to smooth muscle, cardiac muscle, and glands
Neurons • They are the basic functional unit of the nervous system. • They contain three major parts: • 1. cell body. • 2. dendrites. • 3. axon.
Structure
Neurotransmitters CNS • They can be classified into : • 1. Exitatory: • - Ach, glutamate, aspartate , serotonin and NE. • 2. Inhibitory: • - GABA , glycin.
CNS Stimulants • Defination “Stimulants are a substance which tends to increase behavioral activity when administered”
• Signs and symptoms: • 1 - Elevate Mood • 2 - Increase Motor Activity • 3 - Increase Alertness • 4 - Decrease need for Sleep • In case of overdose lead to convulsion and death.
MOA of CNS Stimulants • 1 - Block neurotransmitters reuptake (Most reuptake inhibitors affect either NE or 5 HT(Serotonin) : Cocaine • 2 - Promote neurotransmitters release : Amphetamine • 3 - Block Metabolism - MAO inhibitors (monoamine oxidase): ex. Phenelzine • 4. antagonize the effect of inhibitory neurotransmitter: Picrotoxin & Strychnine •
Neuronal Synapse
Neuronal Synapse
CNS Stimulants • - They can be divided based on their site of action: • 1. Cerebral stimulants (amphetamines) • 2. Medullary stimulants (picrotoxin) • 3. Spinal stimulants (strychnine)
Lab Work • - Objectives: • 1 - To demonstrate effects of some CNS • • stimulant on mice. 2 - After the lab, you should able to handle and inject the mice correctly. 3 - You should able to differentiate between amphetamine, picrotoxin and strychinine regarding the symptoms that induced by each of them.
1 - Amphetamine • MOAs : • Block the reuptake of norepinephrine and • • dopamine into the presynaptic neuron and increase the release of these monoamines into the extraneuronal space. - Clinical use: 1. Narcolepsy. 2. Attention-deficit hyperactivity disorder
Amphetamine • Adverse effects: • - Cardiovascular: Hypertension (7% to 22%, pediatric • • ) - Endocrine metabolic: Weight loss (4% to 9%, pediatric; 11%, adults ) - Gastrointestinal: Abdominal pain (11% to 14%, pediatrics ), Loss of appetite (22% to 36%), Xerostomia (35% ) - Neurologic: Headache (26% ), Insomnia ( ﺍﺭﻕ 12% to 17%, pediatric; 27%, adults ) - Psychiatric: Feeling nervous (6% )
Amphetamine • After injecting, the mice with amphetamine you well notice: - Hair erection • - Licking, gnawing. • - Stereotype • - Sniffing
Picrotoxin • MOA: • Non-competitive antagonist of GABA receptors. • After injecting the mice with picrotoxin you • • well notice: - Clonic convulsion characterized by : 1. Asymmetric 2. Intermittent 3. Spontaneous 4. Coordinated
Strychinine • MOA: • Competitive antagonist of the glycin receptors. • After injecting the mice with Strychinine you well • notice: • • - Tonic convulsion characterized by : 1. Symmetric 2. Reflex in origin 3. Continuous 4. Uncoordinated.
- Slides: 20