Central Nervous System Stimulants

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• Chapter 2.6.
• Central Nervous System Stimulants
• ???????

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Concept central stimulants are drug that enhance
the function of brain

• Action mainly on cerebra, medulla oblongata and
  spinal cord
• Certain degree of selectivity

dosage ? , Action intensity ? , Action range ?
, selectivity ?
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Be caution when taking

• If overdose,strong stimulation will result in
  convulsion.
• Over-inhibition danger to life
• Watching carefully the reaction of patients after
  taking drug. Be careful to control dosage

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Classification based on the action sites

• Pallium stimulants (psychotic stimulants)
• caffeine?methylphenidate
• Spinal cord stimulants
• nikethamide?lobeline
• Nootropic drug
  
• piracetam ?meclofenoxate

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Classification based on chemical structure and
resource

• alkaloids caffeine
• Derivatives of amide piracetam
• phenylethylamine
• others

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camellia
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Caffeine

• trimethylxanthine

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Structure and Nomenclature

• 1,3,7-???-3,7-??-1H - ?? -2,6-??????
• 3,7-Dihydro-1,3,7-trimethyl-1H -purine-2,6-dione
  monohydrate

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Matrix
orientation of H trivial name

• -1H- purine -2,6-dione

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1
7
5
8
4
2
3
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preparation

• Indwell in coffee bean and tea
• Extracted from plant in the early years
• Nowadays, total synthesis

A cup of tea Contains 50mg caffeine
In most people, 85-250 mg of caffeine acts as a
cortical stimulant and facilitates a clear
thinking and wakefulness, promotes an ability to
concentrate. An increased dose leads to excessive
stimulation.
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The naturally occuring methylxanthines
are Caffeine----coffee, tea Theophylline----tea
Theobromine----cocoa
Caffeine
Theophylline
Theobromine
Xanthine
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Process for Total Synthesis
1. pyrimidine ring
2. Purine ring
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Semi-synthesis
caffeine

• Theophylline

(7-methyl-theophylline)
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caffeine and sodium benzoate

• Sodium benzoate and caffeine
• Aqueous solubility increases because of
  intermolecular hydrogen bond
• Formulation of injection

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Distinguished reaction

• Iodine testing reaction
• reddish brown precipitate

• The precipitate dissolve in excess NaOH
  solution

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Distinguished Reaction

• Murexide reaction
• For purine-like alkaloid(oxidised with
  condensation next)

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Mechanism

• Inhibition the activity of phospho-diesterase
  ,decrease the decompose of cAMP.
• Enhancing the exciting process of pallium

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Action

• Treatment of failure central respiration,circulati
  on,nerve and psychotic depressant
• Weak action of heart excitation and diuresis

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Similar drugs

• Xanthine derivatives from nature
• Difference in quantity and position of
  substituted methyl

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Comparison of Pharmacological Action

• Central Excitation
• Caffeine gt theophylline gt theobromine
• Relaxation of smooth muscle and diuresis
• theophylline gt theobromine gt Caffeine

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Usage

• Caffeine central excitation
• theophylline smooth muscle
• relaxation
• diuresis and
• cardiotonic drug
• Theobromine less application

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Piracetam

• Piracetam
• 2-oxo-1-pyrrolidineacetamide
• ???
• ????

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Synthesis
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Action

• ?-lactam drugs for improving brain functions
• Directly action on pallium
• Action of activating, protecting and repairing
  nerve cells
• Improvement of cognition ability of slight and
  moderate dementia patients
• Invalidation for heavy dementia patients
• For treatment of dysmnesia and weak intelligence
  children caused by brain trauma

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Action target

• Adjustment via GABA channel
• Improving the release of acetylcholine from
  hippocampi, increaing the transmission of choline

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Similar drugs

• Exchange substitutes at position 1 and 4

aniracetam
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Central sympathomimetic agents (Psychomotor
stimulants)
Phenylethylamines central stimulant
Phenylpropylamine alcohol (PPA)
diethylpropion
fenfluramine
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Stay away from drug,cherish your life

• Methylphenyl amine (ice sculpture)

• Ecstasy (MDMA)