Peripheral Dopamine Suppression and Elevated Cystatin C in Early Diabetic Nephropathy in Spontaneously Diabetic Rats.

Intrarenal dopamine plays a protective role against the development of diabetic nephropathy during the early stages of the disease. In streptozotocin-induced diabetic mice with a renal-specific catechol-O-methyl transferase knockout, intrarenal dopamine was found to suppress glomerular hyperfiltration, reduce oxidative stress and inflammation, and inhibit fibrosis. However, while dopamine activation in streptozotocin-induced diabetic models has been shown to provide renal protection, the role of dopamine in models of naturally induced diabetes mellitus is still unclear. In the present study, we administered 10 mg/kg p.o. benserazide, a peripheral decarboxylase inhibitor, to Spontaneously Diabetic Torii rats daily, in order to investigate the activation of the renal dopaminergic system during diabetic nephropathy progression. Our findings show that peripheral dopamine decreased urinary 8-iso-prostaglandin F2a and suppressed increases in plasma cystatin C levels. This study demonstrates that a reduction in peripheral dopamine can exacerbate renal dysfunction, even in the early stages of diabetic nephropathy characterized by glomerular hyperfiltration, thereby clarifying the pivotal role of endogenous peripheral dopamine in modulating oxidative stress and kidney performance.

Sex differences in the effects of aromatherapy on anxiety and salivary oxytocin levels.

Objective: Aromatherapy is a holistic healing method to promote health and well-being by using natural plant extracts. However, its precise mechanism of action and influence on the endocrine system remains unclear. Since recent studies reported that a neuropeptide, oxytocin, can attenuate anxiety, we hypothesized that if oxytocin secretion is promoted through aromatherapy, it may improve mood and anxiety. The present study is aimed to investigate the relationship between oxytocin and the effects of aromatherapy with lavender oil on anxiety level, by measuring salivary oxytocin levels in healthy men and women. Methods: We conducted a randomized open crossover trial in 15 men and 10 women. Each participant received a placebo intervention (control group) and aromatherapy with lavender oil (aromatherapy group). For the aromatherapy group, each participant spent a 30-min session in a room with diffused lavender essential oil, followed by a 10-min hand massage using a carrier oil containing lavender oil. Anxiety was assessed using the State-Trait Anxiety Inventory (STAI) before the intervention, 30-min after the start of intervention, and after hand massage, in both groups. Saliva samples were collected at the same time points of the STAI. Results: In women, either aromatherapy or hand massage was associated with a reduction in anxiety levels, independently. Moreover, salivary oxytocin levels were increased after aromatherapy. On the other hand, in men, anxiety levels were decreased after aromatherapy, as well as after hand massage, regardless of the use of lavender oil. However, there were no significant differences in changes of salivary oxytocin levels between the control and aromatherapy groups during the intervention period. Interestingly, there was a positive correlation between anxiety levels and salivary oxytocin levels before the intervention, but a negative correlation was observed after hand massage with lavender oil. Conclusion: The results of the present study indicate that in women, aromatherapy with lavender oil attenuated anxiety with increase in oxytocin level in women, whereas in men, there was no clear relationship of aromatherapy with anxiety or oxytocin levels but, there was a change in correlation between anxiety and oxytocin. The results of the present study suggest that the effect of aromatherapy can vary depending on sex.

Traditional Japanese medicine Kamikihito ameliorates sucrose preference, chronic inflammation and obesity induced by a high fat diet in middle-aged mice.

The high prevalence of obesity has become a pressing global public health problem and there exists a strong association between increased BMI and mortality at a BMI of 25 kg/m2 or higher. The prevalence of obesity is higher among middle-aged adults than among younger groups and the combination of aging and obesity exacerbate systemic inflammation. Increased inflammatory cytokines such as interleukin 6 and tumor necrosis factor alpha (TNFα) are hallmarks of obesity, and promote the secretion of hepatic C-reactive protein (CRP) which further induces systematic inflammation. The neuropeptide oxytocin has been shown to have anti-obesity and anti-inflammation effects, and also suppress sweet-tasting carbohydrate consumption in mammals. Previously, we have shown that the Japanese herbal medicine Kamikihito (KKT), which is used to treat neuropsychological stress disorders in Japan, functions as an oxytocin receptors agonist. In the present study, we further investigated the effect of KKT on body weight (BW), food intake, inflammation, and sweet preferences in middle-aged obese mice. KKT oral administration for 12 days decreased the expression of pro-inflammatory cytokines in the liver, and the plasma CRP and TNFα levels in obese mice. The effect of KKT administration was found to be different between male and female mice. In the absence of sucrose, KKT administration decreased food intake only in male mice. However, while having access to a 30% sucrose solution, both BW and food intake was decreased by KKT administration in male and female mice; but sucrose intake was decreased in female mice alone. In addition, KKT administration decreased sucrose intake in oxytocin deficient lean mice, but not in the WT lean mice. The present study demonstrates that KKT ameliorates chronic inflammation, which is strongly associated with aging and obesity, and decreases food intake in male mice as well as sucrose intake in female mice; in an oxytocin receptor dependent manner.