Alterations of the daily rhythms of HPT axis induced by chronic unpredicted mild stress in rats

Abstract

The relationship between thyroid function and depression has long been recognized. Patients with thyroid disorders are more prone to develop depressive symptoms and conversely depression may be accompanied by various subtle thyroid abnormalities. However, the daily rhythm alteration of the functions of the hypothalamus pituitary thyroid axis (HPT) is uncertain. In the present study, we investigated the effects of chronic unpredictable mild stress (CUMS) on the daily rhythm alterations of triiodothyronine (T3), thyroxine (T4), and Thyroid Stimulating Hormone (TSH) in the plasma. We found that CUMS led to depressive-like behavior and the daily rhythm of T3, T4, and TSH in the plasma being disturbed, as well the plasma levels of T3 and T4 decreased compared to control group. Our findings indicate that CUMS not only induce hypofunction of HPT axis but also the disturbance of daily rhythm of PHT axis in rats.

Short photoperiod condition increases susceptibility to stress in adolescent male rats

“…The unpredictable mild stress procedure consisted of a variable sequence of 12 stressors as described previously [18,19]. The stressors included the following: restraint (1 h), rotation (130 rotations per minute [rpm] for 2 h), forced swim (10 • C for 5 min), cage tilt (overnight), wet sawdust (24 h), cold (4 • C for 1 h), crowding (overnight), reverse light/dark cycle, food or water deprivation (24 h), and tail clamp with long tail clamps (3 min).…”

“…Each behavioral test was performed sequentially, 1 day apart, as described previously [18,19]. The circadian time of the behavioral tests is described below.…”

“…A total of six blood samples were collected. Collections occurred every 4 h (8:00 PM, 12:00 AM, 4:00 AM, 8:00 AM, 12:00 PM, and 4:00 PM) according to our previous studies [18,21,22]. Immediately after each blood sample was drawn, a 1 ml sample was kept in a tube with the anticoagulant ethylenediaminetetraacetic acid.…”

Influence of chronic postnatal stress on pro- and antioxidant system and changes of autonomic balance of cardiac rhythm in rats

“…Він спри-чинює розлади функціонування головного мозку [3], підвищення тромбо утворення і розвиток серцево-судинної патології [4], аритмій, інфаркту міокарда [5], порушення функції системи травлення [6]. Психоемо-ційне перенапруження викликає патологію органів ендокринної системи [7], розвиток оксидативного стресу [8] тощо. Наслідки стрес-реакції залежать від багатьох чинників, включаючи генетичні фактори, особливості навколишнього середовища, стать, вік.…”

Unpredictable Chronic Stress Alters Adenosine Metabolism in Zebrafish Brain

“…The shortterm-period stress response is beneficial to an organism because it improves the chances of the individual for survival [5]. However, unpredictable chronic stress (UCS) affects physiological [6,7], immunological [8,9], endocrine [10,11], and developmental processes [12,13]. UCS changes brain physiology and neural circuits [14] and leads to the development of depressive behaviors [15].…”