Expression of ceruloplasmin in cavernosal tissue of paradoxical sleep deprived rats

Objective: Ceruloplasmin (Cp) is a copper-binding protein expressed in several tissues that plays distinct functions depending on the physiological context. Recently, increased ceruloplasmin expression in cavernosal tissue has been related to diabetes-induced erectile dysfunction. Additionally, several ceruloplasmin activities are to modulate the bioavailability of nitric oxide, which is required for penile erection, suggesting that ceruloplasmin may be a candidate gene that regulates the physiology of penile erection. In previous studies, our group consistently demonstrated that paradoxical sleep deprivation (PSD) increases penile erection in male rats, but the underlying molecular mechanism is still unknown. Methods: We investigated the involvement of ceruloplasmin in paradoxical sleep deprivation-induced penile erection, determining the expression of 2 ceruloplasmin isoforms in cavernosal tissue of rats subjected to paradoxical sleep deprivation, with or without a sleep recovery period. Results: Our findings demonstrated that paradoxical deprivation significantly increased the mRNA level of secreted ceruloplasmin by 1.3-fold compared to the controls, while the expression of glycosylphosphatidylinositol-anchored ceruloplasmin statistically differed only between the paradoxical sleep deprivation and sleep-recovery groups, with ~20% less in the rebound group. However, this subtle modulation of mRNA level was not observed at the protein level. Conclusion: These data indicate that ceruloplasmin is not a factor that directly coordinates erectile function.