Posted by SLS on February 16, 2012, at 2:56:09
In reply to Lou's reply-structural similarities-opioidergic, posted by Lou Pilder on February 15, 2012, at 16:33:46
> > Friends,
> Here is a link that could be helpful IMHHO in this discusssion for those interested.
> Lou
> http://www.biopsychiatry.com/venlafaxine-opioidergic.htmLou.
I cannot begin to explain to you how much this article argues against Effexor having a direct effect on the opioid receptor. What the article does demonstrate is that an intact opioid system is necessary for Effexor to exert its analgesic properties.
Other studies suggest that net effect of antidepressant antinociception involves a release of opioid rather than direct receptor agonism. Even the therapeutic actions of antidepressants seem to depend on an intact opioid system. Brain circuits do not exist in a vacuum.
I posted the abstract below, just in case anyone would like to review it.
- Scott
-------------------------------------------http://www.ncbi.nlm.nih.gov/pubmed/16462101
Yakugaku Zasshi. 2006 Feb;126(2):117-21.Role of the opioidergic system and nitric oxide in the analgesic effect of venlafaxine.
Gültekin H, Ahmedov V.
SourceDepartment of Pharmacology, Erciyes University School of Medicine, Kayseri, Turkey. hgultekin@erciyes.edu.tr
Abstract
The noradrenalin and serotonin re-uptake inhibitor venlafaxine has an analgesic effect that is independent of its antidepressant activity; however, the mechanism of this effect remains to be elucidated. This study was performed to investigate the possible roles of the opioidergic system and nitric oxide (NO) pathway in the analgesic effect of venlafaxine. Eighty Wistar rats of both sexes were allocated to 10 groups. The hot plate test was used to assess the antinociceptive/analgesic effect. The temperature of the hot plate was adjusted to 52.5+/-1 degrees C, the cut-off period was set to be 50 sec; licking of the hind paw was used as a sign of pain perception. Venlafaxine alone (25 mg/kg) showed marked analgesic activity (p<0.05). N-omega-nitro-L-arginine (L-NOARG) alone (20 mg/kg) and naloxone alone (2 mg/kg and 4 mg/kg) showed no analgesic activity (p>0.05). Coadministration of low-dose naloxone (2 mg/kg) and both doses of L-NOARG (20 and 40 mg/kg) with venlafaxine (25 mg/kg) did not modify the analgesic effect but high-dose naloxone (4 mg/kg) decreased it significantly (p<0.05). In conclusion, these results suggest that the opioidergic system but not the NO pathway has a role in the analgesic effect of venlafaxine.
Some see things as they are and ask why.
I dream of things that never were and ask why not.- George Bernard Shaw
poster:SLS
thread:1009503
URL: http://www.dr-bob.org/babble/20120212/msgs/1010415.html