Serotonin, a chemical in your brain, plays an important role in your sex life, including ejaculation.
A chemical messenger, or neurotransmitter, serotonin is also important for your mental health.
Thats why certain antidepressants that affect serotonin can have sexual side effects.
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The Biology of Ejaculation
Ejaculation starts with arousal.
However, there have been human studies as well.
Through research, scientists have learned that several areas of the brain are associated with male sexual function.
The medial preoptic area (MPOA) of thehypothalamusis central to the sexual response.
This is where sexual stimuli from various parts of the body come together for processing.
Studies have shown its possible to make rats orgasm just by activating certain neurotransmitter receptors in their brains.
Role of Neurotransmitters
In humans, serotonin is the neurotransmitter most clearly associated with ejaculation.
SSRIs work by preventing cells from reabsorbing (reuptaking) serotonin.
This means that the signals because of serotonin are extended, lasting for a longer time.
Using SSRI antidepressants long-term extends the time between erection and ejaculation.
Thats one reason why these medications are prescribed to treat premature ejaculation.
Studies in rats have also shown that where serotonin is located in the brain changes its effects.
For example, if serotonin is injected into some parts of the rat brain, it causes delayed ejaculation.
When its put in other areas of the brain, serotonin makes ejaculation happen.
Rat studies have also shown that dopamine stimulation can cause ejaculation.
Often, these patients find it difficultif not impossibleto ejaculate.
The same drugs have been tested as a treatment for people with premature ejaculation.
Similar to SSRIs, antipsychotics seem to extend the time between arousal and ejaculation.
Phases of Ejaculation
Ejaculation is the forceful propulsion ofsemenfrom the body.
It takes place in two phases.
Approximately one-third of seminal fluid comes from the prostate.
Other glands that contribute to seminal fluid production can also be affected by cancer surgeries.
The term orgasm is often used synonymously with ejaculation, but they are not the same thing.
Some people who are multi-orgasmic may have multiple orgasms with only one ejaculation.
Other people are not able to ejaculate at all (anejaculation).
There typically is arefractory periodafter ejaculation before a person again is able to achieve erection and ejaculation.
Erection vs. Ejaculation
An erection is not required for ejaculation to occur.
Ejaculation without an erection is not common, but it is possible.
The most frequent example happens to adolescents while they sleep (nocturnal emissions or wet dreams).
Nocturnal emissions can occur with or without an erection.
Though the physiological pathways that lead to erection and ejaculation are related, they are not the same.
These medications affect the flow of blood in and out of the penis.
They do not affect the release of the semen components or the muscle contractions involved.
Thats one reason why many people who take certain antidepressants experience sexual side effects.
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