these slides help students understanding Anti-parkinson theory & drug.

1. Presentation on-
Anti-parkinson

2. Parkinsonism is A clinical syndrome
comprising four cardinal features bradykinesia , slowness
and poverty of movement, muscular rigidity, resting tremor
which usually abates during voluntary movement and an
impairment of postural balance leading to disturbances of
gait and falling.
The most
common cause of parkinsonism is a loss of the
dopaminergic neurons of the substantia nigra pars
compacta which provide dopaminergic innervations to the
striatum drugs used in the treatment of the parkinsonism
syndrome and other dyskinesias are aimed at restoring the
natural balance of two major neurotransmitters in the CNS :
acetylcholine and dopamine.
The imbalance is a
deficiency in dopamine that results in excessive cholinergic

3. The action of dopamine in the brain are mediated by several
distinct dopamine receptors which are proteins. There have been
identified five dopamine receptors (D1 or D2); but it is currently
accepted that there are only two receptors D1 and D2 abundant in
striatum which are the most imp sites with regard to the
parkinson’s disease.
D1 receptor stimulates the synthesis of intracellular cyclic AMP,
while D2 receptor inhibit cyclic AMP synthesis.
LP
A
DA
Anticholinergic drug
Ach System
(excitatory)
Normal Normal
DA System
(Inhibitory)

4. These are the drugs which are used in the treatment of
parkinsonism art are called as anti parkinsonism drugs.
Classification:-
1. Dopamine agonist : levodopa,
pergolide
2. Dopa decarboxylase inhibitor : carbidopa
3. Dopamine releasing agent : amantadine
4. Synthetic anticholinergics : benztropine,
biperidone
5. Miscellaneous :
phenothiazines
1.Dopamine agonist-
Levodopa 3-(3,4-Dihydroxyphenyl)
alanine
OH
OH
COOH
NH2

5. Mechanism of action-
Dopamine does not cross the blood
brain barrier (BBB), and hence has no therapeutic utility.
However, its immediate metabolic precursor, levodopa, is
transported into the brain by neutral amino acid transporters and
permeates into striatal tissues where it is decarboxylated to
dopamine. The dopamine produced is responsible for the
therapeutic effectiveness of the drug in parkinson’s disease.
Mechanism of action-
pergolide is an ergot derivative that acts as
a. pergolide-

6. At both D1 and D2, receptors in the striatal region. It is effective in
relieving the clinical symptoms of parkinosonis.
2. Dopa decarboxylase inhibitor
a.Carbidopa:-
Mode of action-
1. Carbidopa inhibits aromatic L-aminoacid
decarboxylase in the gut and other peripheral tissues but not in
the brain, because it does not readily cross the blood-brain
barrier. As a reagent it reduces the peripheral conversion of
levodopa to dopamine.
2. therefore when carbidopa and levodopa are
given concomitantly levodopa blood levels are increased and

7. Reduced
3. The combination of carbidopa and levodopa is
called SINEMET, which is considered as the most effective
treatment for parkinson’s disease.
b. Benserazide-
3.Dopamine releasing agent amantadine-

8. Mechanism of action-
in the brain, it appears to block the
reuptake of dopamine at dopaminergic nerve terminals,
thus increasing the conc of dopamine at the synapses. This
facilitates the function of the remaining nigro striatal neuronal
pathways in patients with parkinsonism.
It is also prevented the uncoating of certin viruses and hence
also acts as antiviral agent.
4. Synthetic anticholinergics:-
These drugs diminish tremors
and rigidity, but are generally less effective then levodopa
Mode of action:-
Muscarinic receptor antagonists administered
with levodopa, which in addition to diminishing the cholinergic
striatal effects, may inhibit the reuptake and storage of dopamine
at the striatum

9. Benztropine:-
Biperidine:-

10. 5. Phenothiazine Ethopropazine:-
Uses:-
used in the management of parkinsonism especially for
control of rigidity.