Jump to content

Study: SSRIs hijack dopamine signalling


btdt
 Share

Recommended Posts

SSRI Hijacking Dopamine

 

Summary

Researchers have discovered that antidepressant drugs such as Prozac not only affect levels of the neurotransmitter serotonin in the brain, but also "hijack" dopamine signaling as well--causing it to launch serotonin signals. Their findings offer new insight into how Prozac and other "selective serotonin uptake inhibitors" (SSRIs) work and how they might cause problems in patients taking them.
SSRIs perform their antidepressant function by increasing the concentration of serotonin in the signaling junctions, called synapses, between neurons. This increase alleviates the deficiency of serotonin that causes depression.

As their name indicates, SSRIs prevent uptake of the serotonin after it has performed its task as a chemical messenger that enables one neuron to trigger a nerve impulse in a neighbor. SSRIs prevent this uptake by inhibiting the action of the molecular cargo carriers called transporters that recycle serotonin back to the neuronal storage sacs called vesicles.

Now, however, Fu-Ming Zhou (presently at the University of Tennessee) and colleagues at Baylor College of Medicine have revealed that SSRIs can have more complex effects on neurotransmitter traffic in the brain than just altering serotonin levels. They found that higher serotonin concentrations caused by SSRIs can "trick" transporters of another key neurotransmitter, dopamine, into retrieving serotonin into dopamine vesicles. Dopamine transporters have a low affinity for serotonin, but the higher serotonin levels result in its uptake by the dopamine transporters, found the scientists.

As a result, the normal dopamine-triggered firing from such neurons, in essence, launches two different types of neuronal ammunition, causing "cosignaling."

The researchers were led to study the role of dopamine signaling in SSRI action by previous evidence that dopamine was involved in depression and in the function of antidepressants in the brain. They studied the nature and machinery of serotonin and dopamine signaling by treating mouse brain slices with fluoxetine (Prozac) and other chemicals, and analyzing the effects on the dopamine-signaling machinery.

The relatively inefficient, slow process of "hijacking" of dopamine transporters by serotonin during SSRI treatment could explain why it takes many days of treatment before antianxiety effects are seen, suggested the researchers.

Also, they wrote that their findings may explain why treatment of children with fluoxetine can induce depressive symptoms in adulthood. The researchers wrote that, since serotonin plays a vital role in neuronal development, disruption by fluoxetine of the normal serotonin levels during development could be responsible for such behavioral abnormalities.

They also theorized that such corelease of dopamine and serotonin caused by SSRIs could explain cases of a "potentially life-threatening serotonin syndrome" caused by such situations as dietary overload of serotonin precursors in people taking SSRIs.

The researchers wrote that the relationship between dopamine and serotonin signaling "is likely vital for normal behavior and for the pathology that can be treated with SSRIs." The brain area involved, the ventral striatum, "is critically involved in the neuronal processes of reward and emotional functions." Thus, they wrote, enhanced participation of the striatal dopamine system in serotonin signaling during treatment with SSRIs "may contribute to the therapeutic efficacy of SSRIs."

Original source: 
http://www.eurekalert.org/pub_releases/2005-0... 

Learn more: http://www.naturalnews.com/006639_serotonin_S... 

 

Could be one way it could happen.

WARNING THIS WILL BE LONG
Had a car accident in 85
Codeine was the pain med when I was release from hosp continuous use till 89
Given PROZAC by a specialist to help with nerve pain in my leg 89-90 not sure which year
Was not told a thing about it being a psych med thought it was a pain killer no info about psych side effects I went nuts had hallucinations. As I had a head injury and was diagnosed with a concussion in 85 I was sent to a head injury clinic in 1990 five years after the accident. I don't think they knew I had been on prozac I did not think it a big deal and never did finish the bottle of pills. I had tests of course lots of them. Was put into a pain clinic and given amitriptyline which stopped the withdrawal but had many side effects. But I could sleep something I had not done in a very long time the pain lessened. My mother got cancer in 94 they switched my meds to Zoloft to help deal with this pressure as I was her main care giver she died in 96. I stopped zoloft in 96 had withdrawal was put on paxil went nutty quit it ct put on resperidol quit it ct had withdrawal was put on Effexor... 2years later celexa was added 20mg then increased to 40mg huge personality change went wild. Did too fast taper off Celexa 05 as I felt unwell for a long time prior... quit Effexor 150mg ct 07 found ****** 8 months into withdrawal learned some things was banned from there in 08 have kept learning since. there is really not enough room here to put my history but I have a lot of opinions about a lot of things especially any of the drugs mentioned above.
One thing I would like to add here is this tidbit ALL OPIATES INCREASE SEROTONIN it is not a huge jump to being in chronic pain to being put on an ssri/snri and opiates will affect your antidepressants and your thinking.

As I do not update much I will put my quit date Nov. 17 2007 I quit Effexor cold turkey. 

http://survivingantidepressants.org/index.php?/topic/1096-introducing-myself-btdt/

There is a crack in everything ..That's how the light gets in :)

Link to comment
Share on other sites

 Share

×
×
  • Create New...

Important Information

Terms of Use Privacy Policy