Depression: Ito N

Namiki M, Akaza H, Shimazui T, Ito N, Iwamoto T, Baba K, Kumano H, Koh E, Tsujimura A, Matsumiya K, Horie S, Maruyama O, Marumo K, Yanase T, Kumamoto Y, Anonymous00062, Anonymous00063. · No affiliation provided · Int J Urol. · Pubmed #18452452 No free full text.

This publication has no abstract.

Munakata M, Ichi S, Nunokawa T, Saito Y, Ito N, Fukudo S, Yoshinaga K. · Division of Hypertension and Cardiology, Tohoku University Graduate School of Medicine, Sendai, Japan. · Hypertens Res. · Pubmed #11213026 links to  free full text

Abstract: Night shift work has often been associated with increasing degree and frequency of various psychologic complaints. The study examined whether psychologic states after night work are related to adaptive alterations of the cardiovascular and neuroendocrine systems. We studied 18 healthy nurses (age 29+/-2 years) engaged in a modified rapid shift rotation system (day work, 8:15-17:15; evening work, 16:00-22:00; night work, 21:30-8:30). Blood pressure, heart rate, RR interval variability (L/H and HF power spectrum for sympathetic and vagal activities), and physical activity were measured using a multibiomedical recorder for 24 h from the start of work during the night and day shifts. Plasma ACTH and cortisol concentrations were measured at the end of each shift and at 8:30 AM on a day of rest. Each subject's psychologic state was assessed using a validated questionnaire. Among the parameters measured, scores for confusion, depression, anger-hostility, fatigue and tension-anxiety were highest, and scores for vigor lowest, after a night shift. Systolic blood pressure and heart rate during work were lower during night shift than during day shift (119+/-2 vs. 123+/-1 mmHg, p<0.05 and 75+/-1 vs. 84+/-2 bpm, p<0.001, respectively). Both parameters were lower still (p<0.005 and p<0.05) when measured outside of the hospital under waking conditions following a night shift than following a day shift, even though the levels of physical activity were similar. The HF power spectrum of RR interval variability was greater not only during work (24.2+/-2.1 vs. 18.5+/-1.8 ms, p<0.005) but also during the awake period (29.1+/-2.5 vs. 24.4+/-2.6 ms, p<0.005) after the night shift compared with the day shift. Plasma ACTH and cortisol concentrations were lower after night work than in the day of rest (7.3+/-1.2 vs. 11.5+/-2.3 pg/ml, p<0.1 and 11.1+/-1.1 vs. 14.4+/-1.1 mg/dl, p< 0.05). Systolic and diastolic blood pressures during night shift work and the subsequent awake period correlated positively with scores for vigor and negatively with scores for confusion (p<0.05). Plasma ACTH and cortisol concentrations did not correlate with any psychologic scores. We conclude that psychologic disturbances after night work were associated with altered cardiovascular and endocrine responses in healthy nurses. Some of the psychologic complaints may be attributable to lower waking blood pressure.

Ito N, Yabe T, Gamo Y, Nagai T, Oikawa T, Yamada H, Hanawa T. · Oriental Medicine Research Center, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8642, Japan. · Neuroscience. · Pubmed #18952152 No free full text.

Abstract: A decrease in orexin-A (OX-A) levels has been reported to be associated with depression. It is also well known that stress and depression can disrupt neurogenesis in the dentate gyrus of the hippocampus; however, it is unclear how OX-A is involved in depression and/or neurogenesis. In the present study, we investigated the effect of i.c.v. administration of OX-A on the forced swimming test (FST), an accepted behavioral screen of antidepressant-like activity, and on the cell proliferation with bromodeoxyuridine (BrdU) in the dentate gyrus at 4 days after i.c.v. administration of OX-A. OX-A administration (140 pmol/mouse) led to a significant reduction in animal immobility in the FST, without affecting spontaneous locomotor activities or serum corticosterone levels. In addition, the number of BrdU-positive cells in the dentate gyrus was significantly increased in OX-A-treated mice in vivo; however, OX-A did not affect the percentage of doublecortin-positive cells in the dentate gyrus. The proliferation of neural progenitor cells derived from rat fetal brain was not affected by OX-A treatment in vitro, and the orexin receptor 1 (OXR1) protein was not expressed in these cells. Treatment with the OXR1 antagonist SB-334867 (30 mg/kg, i.p.) blocked both the OX-A-induced decrease in the immobility of FST and increase in BrdU-positive. Moreover, the OX-A-induced increase in neuropeptide Y (NPY)-positive cells in the hilus of the dentate gyrus was blocked by SB-334867. These results suggest that OX-A induces an antidepressive-like effect, at least in part, via the enhancement of cell proliferation in the dentate gyrus. These effects of OX-A also may be partly relevant to the regulation of the NPY system in the hilus of the dentate gyrus.

Ito N, Yabe T, Gamo Y, Nagai T, Oikawa T, Yamada H, Hanawa T. · Department of Clinical Research, Oriental Medicine Research Center, Kitasato University, Tokyo, Japan. · Biol Pharm Bull. · Pubmed #18591778 links to  free full text

Abstract: Rosmarinic acid (RA) is one of major polyphenolic ingredients of Perillae Herba (a leaf of Perilla frutescens), and has an antidepressant-like property in animal models of depression. However, the mechanism(s) underlying this activity are unknown. Recent studies have reported that regulation of hippocampal neurogenesis is associated with the pathogenesis of depression. To elucidate the mode of action of RA-induced antidepressant-like activity, proliferative effect of RA on newborn cells in the dentate gyrus of mouse hippocampus was investigated using immunohistochemical analysis with bromodeoxyuridine (BrdU), a marker of proliferating cells. RA treatment for 7 or 14 d significantly increased in the number of BrdU-positive cells in inverse correlation with significant reductions in immobility in a forced swimming test, an animal model of depression, in a dose-dependent manner. However, locomotor activities were not affected. These results suggest that RA produces an antidepressant-like effect at least in part via the proliferation of newborn cells in the dentate gyrus of the hippocampus.

Ito N, Nagai T, Yabe T, Nunome S, Hanawa T, Yamada H. · Kitasato Institute for Life Sciences, Kitasato University, 5-9-1 Shirokane, Minato-ku, Tokyo 108-8641, Japan. · Phytomedicine. · Pubmed #16516452 No free full text.

Abstract: Koso-san (Xiang-Su-San in Chinese), a Kampo (Japanese herbal) medicine, is used clinically in East Asia for the treatment of depression-like symptoms associated with the initial stage of the common cold, allergic urticaria due to food ingestion, irritable bowel syndrome, chronic fatigue syndrome, insomnia, and autonomic imbalance. However, the antidepressant-like activity of Koso-san has never been evaluated scientifically. In this study, ddY mice subjected to a combination of forced swimming and chronic mild stresses were termed depression-like model mice. The degree of the depression-like state was measured by the animal's duration of immobility using the forced swimming test (FST). Oral administration of Koso-san (1.0 g/kg/body wt./day, 9 days) significantly shortened the duration of immobility of the depression-like model mice in the FST; however, locomotor activity was not affected. Hyperactivity of the hypothalamic-pituitary-adrenal (HPA) axis plays an important role in the pathophysiology of depression. Levels of corticotropin-releasing hormone mRNA expression in the hypothalamus and proopiomelanocortin mRNA expression in the pituitary were significantly increased, and glucocorticoid receptor protein expression in the hypothalamus paraventricular nucleus was downregulated in the depression-like model mice. However, Koso-san ameliorated these alterations to the normal conditions. The results of this study suggest that Koso-san shows the antidepressant-like effect through suppressing the hyperactivity of the HPA axis in depression-like model mice.