Posted by SLS on May 6, 2001, at 18:07:01
In reply to Re: Yohimbe trial results » PhoenixGirl, posted by katz on May 6, 2001, at 8:51:10
Hi Katz.
> Does anyone happen to know the mode of action of Yohimbe?It affects norepinephrine (NE). It blocks a receptor known as NE alpha-2. This receptor is what is known as an autoreceptor because it helps tell the nerve how much of its NE neurotransmitter is still in the synapse. When this receptor is blocked from "seeing" NE, it allows the neuron to continue making and releasing its neurotransmitter beyond what it is "supposed to". The result of more NE can be stimulating.
In addition to NE, there is some evidence that yohimbine stimulates a serotonin (5-HT) receptor known as 5-HT1a. Stimulation of these receptors can reduce the amount of serotonin released.
> Does it act on the dopamine or nor-adrenaline systems? Gaba? My personal experience would indicate that it is a type of stimulant. Any input would be appreciated.
Other neural pathways that use different neurotranmitters are ultimately influenced indirectly by the direct effects of yohimbine on NE and 5-HT neurons. For instance, although yohimbine does not act directly on dopamine (DA) neurons, its activity to increase NE activity and inhibit serotonin activity might ultimately lead to pro-sexual effects that are mediated by DA neural pathways.
I am curious to know how yohimbine affects people with depression and what other drugs they were taking at the time. In addition to its use as an antidote to sexual side effects, it has been used in the past to augment the actions of antidepressants in treatment-resistant individuals. Any input?
- Scott
poster:SLS
thread:61036
URL: http://www.dr-bob.org/babble/20010424/msgs/61818.html