Neurotransmitters and ED

[Flavio]

When a man is sexually aroused, messages from the brain travel down nerves to the penis. Chemicals called 'neurotransmitters' are then released from the ends of the nerves in the penis. Stimulation of the penis can also cause local nerve endings to release neurotransmitter chemicals.

I was reading an excellent book on ED called 'Erectile Dysfunction: Current Investigation and Management' by Ian Eardley and Krishna Sethia and I came across this list of centrally acting neurotransmitters and their effects (pro-erectile or anti-erectile):

Dopamine - Pro-erectile

Serotonin - Anti-erectile (5HT1A), pro-erectile (5HT2C)

Nitric Oxide - Pro-erectile

a-MSH - Pro-erectile

ACTH - Pro-erectile

Opioids - Anti-erectile

GABA - Anti-erectile

Noradrenaline - Anti-erectile

Glutamate - Pro-erectile


This is only a partial reproduction of the list; the diagram featured on the book contains much more information.

Notice how complex the role of serotonin really is: its actions are mainly anti-erectile (this is why most SSRI's inhibit libido and erections) but the activation of some receptors may have pro-erectile effects. And GABA seems to inhibit erections, which is a surprise to me - I thought it had the opposite effect.

Why is this important to us? Well, I'm not an expert but, in theory, substances or products that control these neurotransmitters may be useful and could have a direct impact on erectile function. Apomorphine (brand name Uprima) increases dopamine levels thus improving erections. Rexahn's Zoraxel seems to be even more effective because it acts on dopamine and serotonin levels. This is why I'm so excited about Rexahn's future ED drug: it may be the perfect solution for cases of psychogenic ED and sexual performance anxiety.

[erik]

great list Flavio, good to no the pros and cons when it comes to ED. Where did you get this book? I could not find it on amazon? Also what is all this talk about Rexahn new med coming out? Is there an ETA on this yet?

[Flavio]

great list Flavio, good to no the pros and cons when it comes to ED. Where did you get this book? I could not find it on amazon? Also what is all this talk about Rexahn new med coming out? Is there an ETA on this yet?

Thanks for posting, Erik.

This list is useful but a bit simplistic. Central neurotransmitters interact in a complex way and they're still a great mystery to us: much of what we know comes from animal experiments, especially in the rat, and our ignorance still exceeds our knowledge.

The book is excellent, I can't praise it enough. It's called 'Erectile Dysfunction: Current Investigation and Management' and you can order its second edition (2003) at bn.com

Rexahn's Zoraxel is a new ED drug that shows great promise. Phase 2 trials are currently underway and the drug is expected to be in the market in 2013. You can read more on this on EDG's Future Therapies Section or at rexahn.com

There are fresh news on Zoraxel. Rexahn Pharmaceuticals, Inc. provided an update on the company’s business for the 2009 second quarter. Here's what Dr. Chang Ahn, Rexahn’s Chairman and CEO, had to say about Zoraxel:

"Preliminary reports released from the Phase IIa clinical study for our sexual dysfunction drug candidate, Zoraxel, found that treated subjects demonstrated improved erectile function and significant improvement in the quality of life measures. Underscoring this development, an animal study conducted by Utrecht University in The Netherlands further demonstrated Zoraxel as a potential new-class of therapeutic for the effective treatment of sexual dysfunction. Both of these events represent significant milestones in the development of Zoraxel."