0:00movement in the human body is modulated by the
0:03extra parental system which includes the substantia nigra
0:07something lameque nucleus basal ganglia
0:10and elements the extra parental system can either promote or inhibit movement
0:16let's take a closer look at the key extra parameters structures involved in
0:21Parkinson's disease
0:23the basal ganglia are too large group of nerve cells located near the base of the
0:28brain
0:29which consist of the caudate to Taman
0:32and globus pallidus together the caudate
0:36and put em in form the corpus striatum or stratum
0:39the substantia nigra is a tiny structure located deep within the brain
0:45there are actually two structures but they are typically referred to
0:49as a single entity in the medical literature
0:53normal movement depends on adequate levels the neurotransmitter dopamine
0:58produced by cells in the darkly pigmented zona compacta
1:01above the substantia nigra and delivered to the stratum
1:05and other parts of the brain because this motor pathway involves the
1:09substantia nigra and the striatum
1:11it is known as the nigrostriatal pathway
1:15the synthesis of dopamine begins with the amino acid
1:19tyrosine within the neurons the substantia nigra
1:23Terracina is converted in to leave a dope a through the action of the enzyme
1:27tyrosine hydroxylase
1:28leave a doper is converted into dopamine through the
1:32action of the enzyme dopa decarboxylase
1:35when signaled by an impose traveling down the axe onto the synapse
1:40dopamine is released into the synaptic cleft
1:43sum up the release dopamine binds to dopamine receptors
1:47on the receiving your own triggering a signal that is relayed through neurons
1:52to the Motor Centre
1:53in the cerebral cortex of the brain this signal
1:57eventually travels through the spinal cord to modify activity in muscle cells
2:03free-floating dopamine in the Synoptic gap
2:06may be taken back into the neurons that really stood and stored for future use
2:11in a process called reuptake it may also be converted into other substances
2:17through the action of the enzymes monoamine oxidase B
2:20or MA OB and Caracol
2:23all methyltransferase or COMT
2:26copped
2:30within the stratum there is a delicate balance between dopamine
2:34and acetylcholine another important neurotransmitter
2:37in patients with Parkinson's disease there is massive degeneration of
2:42dopamine producing cells
2:43in the substantia nigra the dopamine supply to the striatum
2:47is gradually reduced this disrupts the balance between dopamine
2:52and acetylcholine resulting in a relative excess
2:55of acetylcholine when sixty percent to 80 percent of dopamine producing cells
3:01in the substantia nigra
3:03are damaged
3:05the extra parameters system loses the ability to effectively promote movement
3:09and the motor symptoms of Parkinson's disease such as resting tremor
3:13rigidity Brady can Asia and postural instability
3:17begin to appear therefore a primary objective 0 pharmacological therapy of
3:23Parkinson's disease
3:24is to increase dopamine levels in the brain