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Test II Notes - SashaVaziri PSB4434 Neurochemistry Chapter...

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Sasha Vazi ri PSB4434 Neurochemistry Chapter 5 There are 2 important classes of catecholamines o Dopamine (DA) o Norepinephrine (norEPI) DA systems have been implicated in Parkinson’s disease Describe the findings supporting the assertion that damage to the nigrostriatal DA system is responsible for the motor disturbances of Parkinson’s disease. o We know that the caudate putamen as well as the globus pallidus and the substantia nigra have been implicated in Parkinson disease. o Specifically the caudate putamen is important in movement o The major thing about dopamine transmitters is that they are very localized…which is good for experimentation because they can be manipulated much easier o The structures associated with DA and the norEPI transmitters are the following Caudate putamen Globus pallidus Substantia nigra (A9) located at the base of the mesencephalon (midbrain) Axons of the dopaminergic neurons in the substantia nigra ascent to the forebrain structure known as the caudate- putamen or the striatum. The pathway from the substantia nigra to the striatum is called the nigrostriatal tract In Parkinson’s disease this tract is severely damaged because most of the prominent symptoms of Parkinson’s disease reflect deficits in motor function (tremors, postural disturbances, and difficulty in initiating voluntary movements) it is clear that the nigrostriatal DA tract plays a crucial role in the control of movement Nucleus accumbens Olfactory tubercule Ventral tegmental area (A10) 2 other important dopaminergic systems arise from the cells of the VTA. The axons that travel to the structures of the limbic system (the nucleus accumbens, septum, amygdale, and the hippocampus) this tract is known as the mesolimbic dopamine pathway. The other tract from the VTA goes to the cerebral cortex, particularly the prefrontal area this group of fibers is
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termed as the mesocortical dopamine pathway. Together the mesolimbic and the mesocortical pathways are very important to psychopharmacologists because they have been implicated in the neural mechanisms of drug abuse as well as schizophrenia o 6-hydroxydopamine (or 6-OHDA) is a neurotoxin which means that it causes injury or death to cells, research shows that when specific tracts are lesioned with 6-hydroxydopamine there are several behavioral deficits associated with loss of DA neurons. Including motor impairment and difficulty initiating voluntary movements. o When the nigrostriatal DA pathway is lesioned only on one side of the brain, the animals display a postural asymmetry characterized by leaning and turning toward the damaged side of the brain due to the dominance of the untreated side, these abnormalities are seen after bilateral or unilateral lesions of the DA system indicating how important this NT is for normal behavioral functioning Parkinson’s Research: o Disease of the brain characterized by progressive loss of neurons and
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