Posted by Shawn. T. on July 23, 2002, at 19:11:16
In reply to Re: enhancing and decreasing, posted by cybercafe on July 22, 2002, at 21:16:21
Schizophrenia definitely involves dopamine neurons, but no drugs acting solely on dopamine receptors will effectively treat schizophrenia.
Drugs with effects on both dopamine and 5-HT2 receptors are better, but the side effects are undesirable.Parkinson's disease is a degeneration of dopaminergic cells in the substantia nigra. L-dopa is a precursor to dopamine, so when a person with Parkinson's disease is given this amino acid, dopamine levels are increased throughout the brain. This is not exactly ideal; all of the dopamine pathways in the brain will be affected by levodopa. Parkinson's disease primarily affects dopamine neurons projecting from the substantia nigra to the dorsal striatum and caudate putamen areas of the brain. This pathway is associated with the iniation of motor plans and motor coordination. Now the reason that l-dopa causes schizophrenia like side effects is because it also affects dopamine neurons in the ventral tegmental area that project to the ventral striatum (nucleus accumbens), amygdala, and prefrontal cortex. Hyperactivity of dopamine neurons in the pathway results in dystonia and psychosis. I'm curious about what effects M 100907 would have on Parkinson's disease.
This makes me angry (I just had to throw it in):
http://www4.infotrieve.com/search/databases/detailsNew.asp?artID=29834771On M-100907 (thromboembolism means the blocking of a blood vessel by a blood clot dislodged from its site of origin).
http://www4.infotrieve.com/search/databases/detailsNew.asp?artID=30302462More on that (plus some information on ketanserin, which is definitely not a highly selective 5-HT2 receptor antagonist):
http://www4.infotrieve.com/search/databases/detailsNew.asp?artID=29749349More on AT-1015 (anyone know who has the patent?)
http://www4.infotrieve.com/search/databases/detailsNew.asp?artID=30820763I apologize for my former lack of knowledge. I am now a lot more up to date with the things that we have learned in the past two years. I have definitely realized that I am going to have to teach myself a lot of cell biology. You really can't make much headway with regards to understanding this stuff when you look solely at the brain in terms of its macro functions. I'm really convinced that bipolar disorders are related to 5-HT2 receptors, although I haven't done much research on that yet. This is because 5-HT2 receptors are excitatory and act through the phospholipase C/ inositol phosphate pathway (I don't believe that any other serotonin receptors directly affect this pathway). How about that.
Shawn
> > I'm curious what you think about why people with Parkinson's often develop schizophrenia type illness when treated with L-dopa or other dopaminergic drugs? That's the one thing I just can't make that fit with the 5HT2 theory. Because their brains clearly have death of dopamine neurons. So it just seems like it would be a dopamine problem. Do you have any thoughts?
>
> Yes it is very likely related to dopamine on some degree, I think schizophrenics might have more dopamine causing excessive firing of D2 receptors in the neocortex i don't remember exactly though
>
> what i can tell you for certain that is i just got a report in the mail showing that the genes encoding norepinephrine (alpha1, 2, 3 beta1, 2), dopamine D2 and D4 corticosteroid and a particular G protein subunit are not shown to be altered in schizophrenia ...
>
> in fact i believe schizophrenics seem to have enlarged ventricles (lateral cerebral ventricles) caused by death or a lack of growth of normal brain cells around the ventricles... i believe it is actually the hippocampus that is decreased in size in schizophrenics... i think failure of the hippocampus to filter out information from the cognitive brain centers (neocortex) to the emotional centers (limbic system) can cause overstimulation ....
poster:Shawn. T.
thread:112626
URL: http://www.dr-bob.org/babble/20020718/msgs/113453.html