A group of mental disorders (schizophrenia, depression) which are consider endogenous in origin Delusions Hallucinations

1. Introduction to CNS
Pharmacology

2. PSYCHOSIS
•A group of mental disorders (schizophrenia, depression) which
are consider endogenous in origin
• Delusions
• Hallucinations

3. Neurosis
•Anxiety and phobias which is regarded as abnormal reaction to
external circumstances
• Sweating
• Tremor
• Palpitation
• Screaming
• Panic reaction

4. CNS drugs: A
challenging problem
•Special significance to mankind
• Clinical indication
• Sense of wellbeing (HIGH)
•Complexity of CNS
• Cellular level not directly related to functional & behavioral level
• Poor understanding of disease

5. General organization of
CNS
•Central Nervous System
• The brain + the spinal cord
• The center of integration and control
•Peripheral Nervous System
• The nervous system outside of the brain and spinal cord
• Consists of:
• 31 Spinal nerves
• Carry info to and from the spinal cord
• 12 Cranial nerves
• Carry info to and from the brain

6. The brain
Cerebral hemi.
Diencephalon
•Brainstem
• Midbrain
• Pons
• Medulla oblongata
•Cerebellum
•Cerebrum
• Cerebral hemispheres
• Diencephalon
• Thalamus
• Hypothalamus

7. Peripheral Nervous
System
•Responsible for communication btwn the CNS and the rest of the body.
•Can be divided into:
• Sensory Division
• Afferent division
• Conducts impulses from receptors to the CNS
• Informs the CNS of the state of the body interior and exterior
• Sensory nerve fibers can be somatic (from skin, skeletal muscles or joints) or visceral (from organs w/i
the ventral body cavity)
• Motor Division
• Efferent division
• Conducts impulses from CNS to effectors (muscles/glands)
• Motor nerve fibers

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

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

10. Cells forming CNS
•Neuron
•Neuroglia
• Astrocytes
• Microglia
• Ependymal cells
• Oligodendrocytes

11. Most neurons have a single axon – a long (up to 1m) process designed
to convey info away from the cell body.
•Originates from a special region of the cell body called the axon hillock.
•Transmit APs from the soma toward the end of the axon where they
cause NT release.
•Often branch sparsely, forming collaterals.
•Each collateral may split into telodendria which end in a synaptic knob,
which contains synaptic vesicles – membranous bags of NTs.

12. Ion channels & NT
receptors
•Voltage-gated channels
• Respond to AP
• Fast action potentials
•Ligand-gated channels (Inotropic)
• opened by binding to NT
• few to tens of milliseconds
•G-protein coupled receptors (Metabotropic)
• Modulate voltage-gated channels
• Tens of milliseconds to minutes
• Direct opening voltage-channel or indirectly through SM

13. Action Potentials
•If stimulus reaches threshold, Na+ channels open and Na+ influx
ensues, depolarizing the cell and causing the AP to increase. This is
the rising phase of an AP.
•Eventually, the Na+ channel will have inactivated and the K+
channels will be open. Now, K+ effluxes and repolarization occurs.
This is the falling phase

14. Chemical Signals
(Synapse)
•One neuron will transmit info to another neuron or to a muscle or gland
cell by releasing chemicals called neurotransmitters.
•The site of this chemical interplay is known as the synapse.
•An axon terminal (synaptic knob) will abut another cell, a neuron,
muscle fiber, or gland cell.
•This is the site of transduction – the conversion of an electrical signal
into a chemical signal.

15. CNS DRUGS
CLASSIFICATION
•Chemical structure
• Benzodiazepines, Butyrophenones
•Pharmacological
• MAO inhibitors, SSRI, Hallucinogens??
•Clinical use
• Antidepressants, Antipsychotic agents, Amphetamines ??

16. WHO Classification
1. Anxiolytic sedatives (hypnotics, sedatives, minor tranquillizers)
“Drugs that cause sleep and reduce anxiety”
Examples
Barbiturates, benzodiazepines and ethanol

17. WHO Classification
2. Antipsychotic drugs (neuroleptics, major tranquillizers, anti-
schizophrenia
“Drugs that are effective in relieving symptoms of schizophrenic illness”
Examples
Phenothiazines and butyrophenones

18. WHO Classification
3. Antidepressant drugs (thymoleptics)
“ Drugs that alleviate the symptoms of depressive illness”
Examples
TCA, MAOI, SSRI

19. WHO Classification
4. Psychomotor stimulants (Psychostimulants)
“Drugs that can cause wakefulness and euphoria”
Examples
Amphetamines, Cocaine, and caffeine

20. WHO Classification
5. Hallucinogenic drugs (psychodysleptics, psychotomimetics)
“Drugs that cause disturbance of perception and of behavior in ways
that cannot be simply characterized as sedative or stimulant effects”
Examples
Lysergic acid diethylamide (LSD), mescaline and phencyclidine

21. Others
•Analgesics (opiate)
•Katamine (anesthetics)
•Nootropics drugs (Piracetam)