Posted by linkadge on November 2, 2007, at 22:07:51
In reply to Re: Dopamine agonists cause sedation. But why?? » linkadge, posted by Astounder on November 2, 2007, at 16:27:44
>Hypothermia is not a normal symptom of the >serotonin syndrome. Do you mean hyperthermia?
Sorry, I should clarify. Objective hypothermia is not, but subjective hypothermia is. "Shivering", or chills, for instance is a symptom of serotonin syndrome.
>Animal studies indicate that hyperthermia from >serotonin syndrome is mediated entirely through >5-HT2a receptors:The first study you mentioned does not prove that this symptom is entirely mediated by 5-ht2a. For starters, cyproheptadine only partially prevented hypothermia. Also ritanserin is not a selective 5-ht2a antagonist. The study itself does not suggest that the hyperthermic responce is *entirely* mediated through 5-ht2a, only that one particualar drug with 5-ht2a antagonistic properties prevented it.
>There are clinical studies in humans proving the >safety of a MAOI with Elavil:Yes, but a few case studies of sucessful combination doesn't make it safe for everbody. From one article I read, severly depressed patients apparently tollerated such combinations with less incedence of SS than when the two drugs happened to interact in drug crossovers. Perhaps a compromised serotonergic system is itself protective againsts serotonin syndrome.
>SSRIs actually reduce plasma and platelet 5-HT >levels with chronic use, though, so they >shouldn't cause cardiac fibrosis.
Why? Cardiac fibrosis is apparently related to potent 5-ht2b agonism of any form. The two recently withdrawn parkinsons drugs, pergolide and cabergoline have no effect on plasma 5-ht, but are potent 5-ht2b agonists. SSRI's too are indirect 5-ht2b agonists. They cause hippocampal proliferation via increased agonism at 5-ht1a. They will affect SERT levels in cardiac tissue too and will functionally increase 5-ht2b agonism there. SSRI's work by increasing receptor 5-ht related events. They are not specific to any particular receptor nor are they specific to SERT levels in the brain.
>Unrelatedly, because 5-HT induces platelet >aggregation, SSRIs are thrombolytic in vitro, >and there are ongoing studies to determine if >SSRIs reduce the risk of infarction and stroke.
Thats short term. Just take an aspirin if your blood is too thick. When the cases of cardiac valve issues start manifesting in another 10-20 years...
Linkadge
poster:linkadge
thread:791344
URL: http://www.dr-bob.org/babble/20071027/msgs/793071.html