The nerves and endothelium of sinusoids and vessels in the penis produce and release transmitters and modulators that control the contractile state of corporal smooth muscles. Although the membrane receptors play an important role, downstream signaling pathways are also important. The RhoA–Rho kinase pathway is involved in the regulation of cavernosal smooth muscle contraction. 
Apomorphine is a non-selective D1/D2 receptor agonist with moderate efficacy and good tolerability in the treatment of mild ED (80). Apomorphine can be administered via subcutaneous injection or sublingually. However, studies have shows a lower efficacy for apomorphine compared to oral sildenafil (81,82). Apomorphine has a set role in the management of PD for non-motor symptoms, and has been reported to cause spontaneous erections and possible hypersexuality in PD men (83,84). Its role in the management of ED has been postulated for men with PD but should be considered as an alternative to sildenafil.
While millions of men, along with their loved ones, suffer from many similar and frustrating symptoms of erectile dysfunction, we understand no two cases are alike. And that’s why your private consultation with one of NuMale Medical Center’s caring medical providers is completely tailored to you and your partner’s wants and needs. We’ll carefully listen to your unique situation to create an impotence treatment plan that’s best for you, taking into account your full medical history.
There are myriad factors, both mental and physical, that may contribute to your erectile dysfunction symptoms. Some of the most common impotence causes include diabetes, hypertension, prostate problems, low testosterone and obesity, which can not only put a damper on your sexual enjoyment, but play a key role in your total male vitality, too. (Even medications that are often prescribed to control some of the aforementioned issues can be behind some of the frustrating symptoms of ED.) There are factors like depression, stress and anxiety that can leave you longing for your glory days, and the coping mechanisms like alcohol and tobacco that can make a roll in the sheets less satisfying for you and your partner. We’ll listen to you with a compassionate ear and thoughtfully consider what may be contributing to your ED symptoms, then draw up your perfect, personalized treatment.
Patient can inject medications directly into the corpora cavernosa to help attain and maintain erections. Medications such as papaverine hydrochloride, phentolamine, and prostaglandin E1 (alprostadil) can be used alone or in combinations to attain erections. All of these medications are vasodilators and work by increasing blood flow into the penis. Prostaglandin E1 (Caverject, Edex) is easier to obtain; however, it is associated with penile pain in some individuals. The use of combinations of two or three of these medications can decrease the risk of having penile pain.
Specially designed vacuum devices to produce erections have been used successfully for many years. Vacuum devices are safe, relatively inexpensive, and reliable. Vacuum devices do not require surgery. Vacuum devices are available over the counter or by prescription. It is important to make sure that the vacuum device have a mechanism to prevent too high of a vacuum (negative pressure).
ICI therapy often produces a reliable erection, which comes down after 20-30 minutes or with climax. Since the ICI erection is not regulated by your penile nerves, you should not be surprised if the erection lasts after orgasm. The most common side effect of ICI therapy is a prolonged erection. Prolonged erections (>1 hour) can be reversed by a second injection (antidote) in the office.