Neurobiology & Delayed Ejaculation
Neurobiology Of Male Ejaculation Problems
There isn’t much scientific research on the neurobiology of delayed ejaculation. However Marcel Waldinger has researched the ejaculatory process in male rats, and he’s discovered there are certain nervous pathways in the central nervous system which are responsible for mediating ejaculation.
Stand By For A Bit Of Sexual Science!
Increased serotonergic neurotransmission in the synapses between neurons leads to delayed ejaculation, and the activation of specific serotonin receptors by 5HT molecules leads to either rapid or delayed ejaculation (DE).
To be more specific, the activation of 5HT2c postsynaptic receptors gives rise to delayed ejaculation whereas activation of 5HT1a postsynaptic receptors facilitates ejaculation.
So rats fall into three groups: sluggish ejaculators, normal ejaculators, and rapid ejaculators, which seems to be a remarkable parallel with the sexual behavior in the human male. So maybe, just maybe, research on this group of rats may lead to more insights into the neurobiology of lifelong delayed ejaculation in the human male.
When a man starts having difficulty ejaculating later in life there are other things to look for: as already mentioned, medication such as SSRIs and tricyclic antidepressants may be responsible for delayed ejaculation, as can the antipsychotics and anxiolytics.
And androgen deficiency due to ageing can be responsible for a slower sexual response. In addition, as you may imagine, traumatic or surgical spinal injuries that damage the lumbar sympathetic ganglia connecting nerves can be responsible for failure of, or delay, in ejaculation.
One of the more interesting pieces of ejaculatory research on animals has revealed that rats reared in isolation are, at least initially, incapable of achieving ejaculation, or will show no interest, when they’re exposed to receptive females.
This contrasts with rats which have grown up in any kind of social environment – these rats engaged in normal sexual behavior.
The Social Environment
And Its Impact On Male Ejaculation
Interestingly enough, in the majority of the rats reared in isolation, sexual performance gradually improved as the rats became more experienced.
One implication of this is that a man’s trouble ejaculating may be induced by negative experiences or inadequate experience in the sexual arena during early or mater adulthood.
Adjusting the level of sexual experience that rats have had can produce something that appears to mimic ejaculation problems in men.
Rats with no previous experience of sexually active female rats which were exposed to female rats at the receptive phase of their estrus cycle resulted in 82% of the male rats showing some signs of sexual activity with a failure of ejaculation.
Treating them with chemicals which were antagonistic to 5HT1a receptors enhanced sexual behavior to the level of sexually experienced rats.
Clearly much of this type of research has to be conducted on rats since it’s ethically impossible to conduct on humans, and whether the results are transferable to a human population is open to question.
But this does suggest that sexually naive male rats can in fact gain enough sexual experience to perform sexual activities in a way that matches sexually experienced rats in a comparatively short period of time.
Brain Biochemistry At Work Again!
Studies have shown there are several compounds which can increase sexual activity in rats, ranging from Viagra through to low doses of the hormone melatonin as well as more sophisticated 5HT1a receptor agonists. The implication to be drawn from all this, of course, as stated above, is that there are specific neurobiological mechanisms that are responsible for hyposexual behavior in sexually inactive rats.
Such studies may provide an indication of the neurobiological mechanisms that govern delayed ejaculation and even complete absence of ejaculation in men. The difficulty is in conducting studies in an ethically appropriate way.
A potentially more fruitful approach to gain evidence of physiological brain mechanisms in DE, or to explore the neurobiology of ejaculation and how that interacts with emotional and psychological factors is by use of the intravaginal ejaculatory latency time or IELT – this scientific methodology which gives a baseline by which different treatments can be effectively compared.
Nonetheless, psychopharmacological animal research is still crucial to the investigation of DE.
As far as the scientific community is concerned the frequency of retarded ejaculation appears to be extremely low, and the development of a drug for this dysfunction would be extremely expensive, which means there is almost no chance that a pharmaceutical company will agree to spend the necessary funds on research and investment in the immediate future.
Nothing is known about the brain regions associated with ejaculatory dysfunction, although an interesting PET scan on men who were not able to ejaculate was performed in a study conducted in 2004.
And what was found? That successful ejaculation is marked by increases in cerebral blood flow in the mesodiencephalic transition zone and cerebellum. PET scans taken during unsuccessful attempts at ejaculation revealed that the brain cortex was activated in the right orbitofrontal cortex, the left dorsal prefrontal cortex and bilaterally in the anterior insular.
When compared with scans taken during successful attempts at masturbatory ejaculation, the scientists found that the cortex was more active in non-ejaculatory men than it was in ejaculatory men, especially in the anterior amygdala and left temporal pole.
These brain structures are associated with fear behavior and vigilance, leading the researchers to conclude that the unsuccessful attempts at ejaculation may actually mirror the real-life situation of men who have difficulty ejaculating.
And what this may mean is that men are inhibited from ejaculation by fear – which seems easy to understand but may not completely explain why these men are still able to maintain a strong erection.
Also important is the fact that a moderate but unavoidable delay develops before ejaculation as a man gets older.
This may be associated with androgen deficiency, and spinal injuries which have damaged the lumbar sympathetic ganglia and associated connecting nerves, as well as abdominal surgery and neurodegenerative disorders – including diabetic neuropathy and multiple sclerosis, for example.
In addition, a wide range of SSRIs, tricyclic antidepressants, antipsychotics and alcohol may delay ejaculation.