Sub-cortical and brainstem sites associated with chemo-stimulated increases in ventilation in humans

We investigated the neural basis for spontaneous chemo-stimulated increases in ventilation in awake, healthy humans. Blood oxygen level dependent (BOLD) functional MRI was performed in nine healthy subjects using T2weighted echo planar imaging. Brain volumes (52 transverse slices, cortex to high spinal cord) were acquired every 3.9 s. The 30 min paradigm consisted of six, 5-min cycles, each cycle comprising 45 s of hypoxic-isocapnia, 45 s of isooxic-hypercapnia and 45 s of hypoxic-hypercapnia, with 55 s of non-stimulatory hyperoxic-isocapnia (control) separating each stimulus period. Ventilation was significantly (p < 0.001) increased during hypoxic-isocapnia, isooxic-hypercapnia and hypoxic-hypercapnia (17.0, 13.8, 24.9 L/min respectively) vs. control (8.4 L/min) and was associated with significant (p < 0.05, corrected for multiple comparisons) signal increases within a bilateral network that included the basal ganglia, thalamus, red nucleus, cerebellum, parietal cortex, cingulate and superior mid pons. The neuroanatomical structures identified provide evidence for the spontaneous control of breathing to be mediated by higher brain centres, as well as respiratory nuclei in the brainstem

Obstructive sleep apnoea and sexual function in men

Obstructive sleep apnoea (OSA) is associated with sexual dysfunction. Untreated OSA and erectile dysfunction (ED) have both been identified as being indicative of a high risk of developing cardiovascular disease. Treatments for ED, such as testosterone supplementation or PDE-5 inhibitors, and for OSA, such as Continuous Positive Airways Pressure (CPAP) are both readily available. The effects of these treatments on the other associated conditions have not been fully assessed. The efficacy of testosterone supplementation, in untreated OSA, on sexual function and quality of life has not been investigated. PDE-5 inhibitors are an established treatment for erectile dysfunction, however, there is a paucity of information regarding their efficacy in OSA, and there is a theoretical risk of worsening of OSA with their use. CPAP, in some observational and non-treatment or alternative treatment controlled studies, has been shown to improve erection function in men with OSA, however the majority of these studies have been in men with OSA, with and without ED. Two randomised controlled trials investigating the effects of testosterone in untreated OSA (n=67), and the effects of CPAP and a PDE-5 inhibitor in men with OSA and ED using a factorial design (n=61) were performed. Sleep, sexual function and quality of life was assessed. CPAP increased the quantity of nocturnal erections and a PDE-5 inhibitor improved their quality. However, neither CPAP use, exogenous testosterone nor a PDE-5 inhibitor improved subjective erectile function in men with OSA. Post-hoc analysis showed that adherent CPAP use (>4hours per night) increased subjective erectile function and sexual desire, as well as several parameters of quality of life in men with OSA and ED. Testosterone also increased sexual desire in men with OSA

Obstructive sleep apnoea and sexual function in men

Obstructive sleep apnoea (OSA) is associated with sexual dysfunction. Untreated OSA and erectile dysfunction (ED) have both been identified as being indicative of a high risk of developing cardiovascular disease. Treatments for ED, such as testosterone supplementation or PDE-5 inhibitors, and for OSA, such as Continuous Positive Airways Pressure (CPAP) are both readily available. The effects of these treatments on the other associated conditions have not been fully assessed. The efficacy of testosterone supplementation, in untreated OSA, on sexual function and quality of life has not been investigated. PDE-5 inhibitors are an established treatment for erectile dysfunction, however, there is a paucity of information regarding their efficacy in OSA, and there is a theoretical risk of worsening of OSA with their use. CPAP, in some observational and non-treatment or alternative treatment controlled studies, has been shown to improve erection function in men with OSA, however the majority of these studies have been in men with OSA, with and without ED. Two randomised controlled trials investigating the effects of testosterone in untreated OSA (n=67), and the effects of CPAP and a PDE-5 inhibitor in men with OSA and ED using a factorial design (n=61) were performed. Sleep, sexual function and quality of life was assessed. CPAP increased the quantity of nocturnal erections and a PDE-5 inhibitor improved their quality. However, neither CPAP use, exogenous testosterone nor a PDE-5 inhibitor improved subjective erectile function in men with OSA. Post-hoc analysis showed that adherent CPAP use (>4hours per night) increased subjective erectile function and sexual desire, as well as several parameters of quality of life in men with OSA and ED. Testosterone also increased sexual desire in men with OSA