Hello in this video we’re gonna look at the pharmacology of parkinson’s so the main drugs involved in the treatment of parkinson’s disease if you haven’t watched part my video on parkinson’s pathophysiology i recommend you watch that to get a better understanding of the disease and so hopefully that will make this video a lot easier so parkinson’s disease is a
Neurodegenerative disease that affects an area of the brain known as a substantial mainly this area and in the substantia you have important neurons arising from there known as a dopaminergic neurons and these guys they secrete dopamine which is important in essentially contributing to a controlled movement pattern so let us look at a normal non in this area
And compare it to the one in parkinson’s disease so so let’s look at a normal one first so here we have a dopaminergic neuron dopaminergic neurons contain dopamine vesicles in the terminal here and these guys they are able to secrete dopamine and when they secrete dopamine it will essentially either either stimulate or it will inhibit these gaba nergic neurons
Here these governors ignorance are found in an area of the brain known as a coated striatum the coated striatum is made up of the caudate nucleus and coda a putamen they again these in this area contains gaba nergic neurons which receives information from the dopa nergic neurons from the substantial niagra so these guys have dopamine receptors when dopamine is
Released it binds unto these dopamine receptors and either stimulates or inhibits the gabaergic neurons within the dome energic wrist neurons here we have an enzyme monoamine oxidase and these are these guys essentially break down the dopamine after it’s being used so it sort of helps in the recycling process so parkinson’s disease is where we have degeneration of
Dopaminergic neurons this means that we have no like not much dopamine or no dopamine being produced by the cells in this area now these neurons in the central nervous system in the substantia their surround they’re surrounded by they’re protected by the blood-brain barrier just an important side note ok so again in a parkinson’s disease patient we have decrease
In dopamine in the synaptic cleft because no dopamine is being produced because the neurons are dying similarly we have again the enzyme of course monoamine oxidase which will still break down the dopamine if if it were being produced so essentially the treatment for parkinson’s disease is to provide more dopamine that is one logical reason so a drug that could
Be given as it is known as liver dopa so levodopa is a precursor to dopamine and it’s given because it is able to pass the blood-brain barrier okay so it can go into the neuron where as dopamine cannot pass the blood-brain barrier that is why we give levodopa unfortunately in the peripheral system or in the blood vessels levodopa can be broken down by dopamine
Carboxylase to dopamine and so if it gets converted to dopamine before it reaches the brain that’s really not helpful so usually we usually there’s another drug which is given in combination with levodopa these guys are known as decarboxylase inhibitors decarboxylated inhibitor a main example is carbidopa and these guys again they prevent the peripheral breakdown
Of levodopa dopamine allowing levodopa to essentially move into the dopaminergic neurons that are left over to produce more dopamine however levodopa in the periphery can also be broken down to 300 md by compt and so you also can administer a comped inhibitor again comped inhibitors prevents the peripheral breakdown of levodopa so if livered so levodopa isn’t
Able to pass the blood-brain barrier into the dopaminergic neurons in the neurons levodopa can be converted to dopamine by carboxylase dopamine carboxylase and so this neuron is able to produce and release more dopamine lessening the symptoms the signs and symptoms of parkinson’s disease so those were these drugs the levodopa is first-line for parkinson’s disease
However there’s other drugs that could also be given and they target different things so for example you can actually have dopamine agonists and these guys essentially bind and activate dopamine receptors so they mimic the effects of dopamine you can also administer monoamine oxidase inhibitors so these guys inhibit the enzyme within the neuron that would other
Otherwise break down dopamine so they prevent these guys prevents the breakdown of dopamine allowing more dopamine to be used for longer periods of time so i hope that made sense again the drugs used main drugs used on levodopa which has to be administered with the peripheral dopamine carboxylase inhibitors such as carbon dopa and then you can also have the dopamine
Agonists or the monoamine oxidase inhibitors i hope you enjoyed this video on the pharmacology of parkinson’s disease it was just an overview thank you very much for watching
Transcribed from video
Pharmacology – Parkinson's Disease By Armando Hasudungan
