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5,7-Dihydroxytryptamine (5,7-DHT) is a neurotoxin which causes the depletion of serotonin. Moreover, the serotonergic system is the regulator of the blood glucose level. However, the role of centrally located serotonergic system in blood glucose regulation after D-glucose feed and immobilization (IMO) stress was not clearly characterized yet. Thus the present study was designed to examine the effect of 5,7-DHT administered intracerebroventricularly (i.c.v.) or intrathecally (i.t.) on the blood glucose level in D-glucose-fed and immobilization stress models. Mice were pretreated once i.c.v. or i.t. with 5,7-DHT (from 10 to 40 µg) for 3 days and D-glucose (2 g/kg) was fed orally. The blood glucose level was measured at 0, 30, 60 and 120 min after D-glucose feeding and immobilization stress initiation. We found that i.c.v. or i.t. pretreatment with 5,7-DHT attenuated the blood glucose level in both animal models. D-glucose feeding causes an increase in plasma insulin level, whereas the plasma cortico...

Effects of histamine receptors agonists or antagonists administered centrally (supraspinally or spinally) on immobilization stress-induced blood glucose levels were studied in Institute for Cancer Research mice. Mice were pretreated intracerebroventricularly (i.c.v.) or intrathecally (i.t.) with histamine (H1, H2, H3 and H4) receptor agonists or antagonists 10 min prior to immobilization stress (IMO) stimulation for 30 min. We found that the increased blood glucose level induced by IMO was attenuated by the i.c.v. pretreatment with α-methylhistamine (H3 agonist). However, H3 antagonist, H1, H2 and H4 receptor agonists and antagonists did not affect the blood glucose level. Also, i.t. pretreatment with α-methylhistamine or VUF 8430 attenuated the increased blood glucose level induced by IMO. In addition, cetirizine and carcinine enhanced the increased blood glucose level induced by IMO. However, the blood glucose level was not affected by H1 and H2 receptor agonists, H2 and H4 receptor antagonists. Cortico...

Corticotropin-releasing hormone (CRH) is known to be involved in both antinociceptive and nociceptive processing. In the present study, we examined the role of the CRH receptor 1 in the regulation of nociception in mice. First, we found that CRH mRNA level was elevated in the hypothalamus or hippocampus by intraperitoneal (i.p.) injection with 1% acetic acid, intraplantar injection of 5% formalin, or intrathecal (i.t.) injection of substance P (0.7 μg/5 μl). Nociceptive behavior induced by acetic acid, formalin, or substance P were reduced in CRHR1 heterozygous (CRHR1+/−) mice compared to that in C57BL6 (wild type, CRHR1+/+) mice group. Furthermore, administration with CRHR1 antagonists such as CP 154526 (10 mg/kg, i.p.) or α-helical CRF 9-41 (10 μg/5 μl, intracerebroventricular [i.c.v.]) attenuated nociceptive behaviors observed in the substance P and writhing pain models. Our results suggest that CRHR1 might play an important role in the regulation of nociception, especially, toward nociceptive activati...

Proinflammatory cytokines have been implicated in the production of neuropathic pain. We have previously reported that several ginsenosides produce antinoception. Especially, we have previously demonstrated that ginsenosides administered supraspinally reduce pain behaviors induced by proinflmmatory cytokines administered spinally. However, spinal action of ginsenosides in the regulation of proinflammtory cytokine-induced pain behavior has not been characterized yet. In the present study, we investigated the effects of ginsenosides following intrathecal treatment on pain behaviors induced by pro-inflammatory cytokines such as tumor necrosis factor-alpha (TNF-α), interleukin-1β (IL-1β), and interferon-γ (IFN-γ) injected intrathecally. The ginsenosides such as Rb1, Rb2, Rc, Rf, Rg1, and Rg3 pretreated intrathecally reduced the pain behavior induced by TNF-α, IL-1β, and IFN-γ injection. However, ginsenoside Rd and Re treated intrathecally did not affect the pain behavior induced by proinflammatory cytokines i...

The relationship between pain stimulation and the blood glucose level was studied in ICR mice. We examined the possible change of the blood glucose level after the pain stimulation induced by acetic acid injected intraperitoneally (i.p.),, formalin injected subcutaneously (s.c.) into the hind paw, or substance P (SP), glutamate, and pro-inflammatory cytokines (TNF-α and IFN-γ) injected intrathecally (i.t.). We found in the present study that acetic acid, formalin, SP, TNF-α, and IFN-γ increased the blood glucose level. The blood glucose level reached at maximal state 30 min and returned to normal level 2 h after the pain stimulation in a fasting group. Furthermore, acetic acid, formalin, SP, TNF-α, and IFN-γ caused the elevation of the blood glucose level in d-glucose-fed group only in an additive manner. However, i.t. injection of glutamate did not alter the blood glucose level in a fasting group. In contrast, i.t. injection of glutamate enhanced the blood glucose level in the d-glucose-fed grou...

Artemisia capillaris Thunb. is widely used in the herbal medicine field. This study describes the antidepressant effect of a flavonoid (chlorogenic acid) isolated from the Artemisia capillaris Thunb. The expression of the pituitary gland and hypothalamic POMC mRNA or plasma β-endorphin levels were increased by extract of Artemisia capillaris Thunb. or its flavoniod administered orally. In addition, antidepressant activity was studied using the tail suspension test (TST), the forced swimming test (FST) and the rotarod test in a chronically restrained immobilization stress group in mice. After restraint stress (2 h/day for 14 days), animals were kept in a cage for 14 days without any further stress, but with drugs. Mice were fed with a diet supplemented for 14 days and during the behavioral test period with chlorogenic acid (30 mg/kg/day). POMC mRNA or the plasma β-endorphin level was increased by the extract of Artemisia capillaris Thunb. and its flavoniod. In addition, the immobility time in TST ...