In article <6iNC5.1062$m06.57962 at news1.news.adelphia.net>, "MS"
<marshmallow5 at yahoo.com> wrote:
> > Have other dopamine dependent conditions been described?
>> Parkinson's disease namely, which does show a disproportionately high
> rate
> of depression. Dopamine has been implicated as playing a role in several
> other disorders including schizophrenia, ADHD, Lesch-Nyhan disease, and
> drug/alcohol addictions to name a few.
>> > I there any validity in the above theory?
>> Youre hypothesis seems consistent. I wouldn't say it's the only possible
> explanation, but it seems to make sense. Whatever the problem is, the
> drug
> treatment seems to help. By analogy, schizophrenia may not be a disorder
> of
> dopamine levels or receptors, but drugs that block dopamine do alleviate
> the
> problem. Another example: Parkinson's disease results from a lack of
> dopamine in the basal ganglia, which is treated by increasing dopamine
> activity OR by blocking acetylcholine receptors. A treatment that works
> only
> means it restores somewhat of a functional balance. Whether or not its
> the
> actual cause (or one of the causes) is another step.
>> > Does melatonin inhibit dopamine production? (producing seasonality)
>> To echo my last statement somewhat, SAD may cause an imbalance of
> activity
> in limbic and frontal areas of sufferers and dopamine may just be
> restoring
> the proper balance. But what youre suggesting is another logical
> possiblility: melatonin may directly or indirectly modify DA function. Do
> a
> search on medline. Unfortunately, there is also dopamine in the retina,
> so
> there's probably going to be tons of research on melatonin's effects on
> retinal dopamine which you'd have to sift through.
>> > Could bipolar 1 disorder be serotonin dependent and bipolar 2 disorder
> > be
> > dopamine dependent?
>> I think other things are at work in bipolar disorder as well. I know more
> recent research has focused on intracellular messengers and G proteins.
>> > Is human happiness as simple as a sole chemical and it's activity?
>> I 'd have to say that the emotion of happiness, as all emotions and
> subjective experience are an aspect of brain function. That means a
> pattern
> of activity in related brain areas. I regard mind, brain, and behavior
> as
> three aspects of the same phenomenon. The chemical messengers
> (neurotransmitters etc.) modify the activity of brain areas responsible
> for
> mood (namely frontal-subcortical and limbic structures).
>> I hope this helps.
>> --
> Marcello
>marshmallow5 at yahoo.com>> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> -
> -
>> Nobody on his deathbed ever said,
> "I wish I had spent more time at the office."
>> Paul Tsongas
>> - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - - -
> -
> -
> jonconx <jonconx at MEblueyonder.co.uk> wrote in message
> news:JM7A5.7498$gw4.955907 at news1.cableinet.net...> > I suffer from dopamine dependent Seasonal Affective Disorder. In fall
> > I
> > start to become depressed (this is characterized by hypersomnia and
> > paranoia). This peaks in mid-winter and then fades out to become
> hypomania
> > in May. This is now controlled with bromocriptine which is a
> > dopaminergic
> > drug. This is titrated against mood and used in the Fall and Winter
> months.
> > Starting out with just 1mg at the beginning of September and peaking
> > with
> > 30mg in the last couple of months of January. This is then faded out
> > to a
> > zero dose at the start of April . Hypomania does not subsequently
> > occur
> > with this treatment.
> >
> > Small fluctuations in mood can occur with alcohol use, presumably as
> > there
> > is dopamine release and a high when intoxicated and then a lack of
> dopamine
> > activity a few days later leading to depression and paranoia. This
> resolves
> > within a couple of days. Needless to say, I don't drink anymore and
> > small
> > fluctuations in mood rarely occur.
> >
> > I believe that with a lack of dopamine activity (i.e. in the winter)
> > the
> > post-synaptic receptors become super-sensitive (dopamine hungry). This
> > means they have a 'hair-trigger' and can fire inappropriatly. In other
> > words there is noise in the system. This leads to paranoid thinking
> > and
> the
> > overall lack of activity leads to inactivity, hyposomnia and
> > depression.
> In
> > addition it could mean that adjacent receptors could fire
> > inapproprately
> and
> > lead to thoughts which are not related clouding the issue and adding to
> > paranoid/psychotic thinking. After a period of dopamine deprevation
> > the
> > super-sensitive receptors can then 'over fire' when subjected to higher
> > levels of dopamine (e.g. in the spring). This leads to hypomanic
> behaviour
> > with increased motor activity and mood which eventually settles down to
> > a
> > normothymic condition (till the fall).
> >
> > This can be backed up with by the action of dopaminergic drugs at
> different
> > stages of the disease process. When there is normal mood (say
> > july)with
> no
> > medication, the addition of dopaminergic drugs causes a slight lift in
> mood.
> > However, if thouroughly depressed and untreated(say January), the
> > addition
> > of a dopaminergic drug produce profound mania in the short term due to
> > supersensitive post-synaptic receptors over -firing. The receptors
> > then
> > downregulate and normal mood is restored.
> >
> > I wonder if anyone could answer the following questions:
> >
> > Have other dopamine dependent conditions been described?
> >
> > I there any validity in the above theory?
> >
> > Does melatonin inhibit dopamine production? (producing seasonality)
> >
> > Could this relate to seasonal control of dopamine synthesis and/or
> > severe
> > receptor instability?
Not sure about this. In seasonal breeders, I believe dopamine is
regulated by melatonin via the tuberoinfindibular pathway (hardly every
mentioned this is a third set of DA cells, asides from VTA and SN). It
might be the other way around. In either case, this mechanism is
conserved from insects all the way up to hamsters (which are seasonal
breeders). Of course, mice, rats and humans are not seasonal breeders,
and they are the animals that are primarily studied. Of course, the
pineal is there as is the tuberal pathway, which means it may have some
effects we dont know about. My recall is poor, since I learned this so
long ago, maybe someelse can comment. basically, I recall that long day
light periods elicit a lot of melatonin production in the pineal, this
circulates in the blood, producing more DA, making you horny in the
summer
> >
> > Are other psychotic disorders related to dysregulation of dopamine
> > receptors?
> >
> > Is dopamine function related to immune function (if untreated, in
> mid-winter
> > I develop oral and nasal warts (yuk!) and developed such severe
> > moluscum
> > contagiosum lesions one winter I was believed to have AIDS (I'm HIV
> > negative)
> >
> > If antipsychotic drugs control schizophrenia, why do they block
> pre-synaptic
> > receptors and cause an overall increase in dopamine concentrations,
> > could
> > they be working on above mechanisms?
> >
> > Could bipolar 1 disorder be serotonin dependent and bipolar 2 disorder
> > be
> > dopamine dependent?
> >
> > Is human happiness as simple as a sole chemical and it's activity?
> >
> > I am no neurobiologist, but if anyone could give me some guidence on
> > the
> > above, I would be most grateful
> >
> > Yours John Connelly
> > Birmingham, England
> >
> > Email: jonconx at yahoo.com>>