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In the course of isolating preventive agents against sepsis based on the in vivo assay model, eleven known compounds, (-)-catechin (1), catechin-7-O-β-apiofuranoside (2), catechin-7-O-α-Lrhamnopyranoside (3), catechin-3-O-α-L-rhamnopyranoside (4), catechin-7-O-β-D-glucopyranoside (5), butyl (+)-5'-methoxyisolariciresinol-9'-O-β-D-xylopyranoside (6), lyoniside (7), nudiposide (8), α-nigerose (9), butyl α-D-fructofuranoside (10), and procyanidin B(3) (11) were isolated from the root barks of Ulmus davidiana var. japonica. Compounds 2, 6, and 8 significantly protected against sepsis in a mouse model with survival rates of mice exposed to 10 mg/kg of LPS/D-GalN ranged from 80%-100%. Among them, 8 exhibited the most potent protective effect and decreased the plasma levels of TNF-α, IL-10 and ALT activity.

In the present study, the antinociceptive profiles of eugenol were examined in ICR mice. Eugenol administered orally (from 1 to 10 mg/kg) showed an antinociceptive effect in a dose-dependent manner as measured in the acetic acid-induced writhing test. Duration of antinociceptive action of eugenol maintained at least for 30 min. Moreover, the cumulative response time of nociceptive behaviors induced by an intraplantar formalin injection was reduced by eugenol treatment during the 2(nd) phases. Furthermore, the cumulative nociceptive response time for intrathecal injection of substance P (0.7 μg) or glutamate (20 μg) was diminished by eugenol. Intraperitoneal pretreatment with yohimbine (α2-adrenergic receptor antagonist) or naloxone (opioid receptor antagonist) attenuated antinociceptive effect induced by eugenol in the writhing test. However, methysergide (5-HT serotonergic receptor antagonist) did not affect antinociception induced by eugenol in the writhing test. Our results suggest that eugenol shows an antinociceptive property in various pain models. Furthermore, this antinociceptive effect of eugenol may be mediated by α2-adrenergic and opioidergic receptors, but not serotonergic receptor.

We have evaluated the possible underlying mechanisms of immobilization stress-induced analgesia (SIA) by behavioral cross-tolerance studies and molecular studies. In the behavioral studies, the cross-tolerance between single or repeated immobilization SIA and the antinociceptive effects of β-endorphin, morphine, 5-hydroxytryptamine (5-HT), or WIN55,212-2 were assessed. Both single and repeated (×7) immobilization stress significantly attenuated the β-endorphin and 5-hydroxytryptamine-induced antinociception in the 2nd phase of formalin response, respectively. However, these cross-tolerances disappeared in prolonged repetition of the stress (×14). Neither single nor repeated (×7 and ×14) immobilization stress affected the antinociceptive effect of morphine or WIN55,212-2 at all. We also found that immobilization stress activated hypothalamic proopiomelanocortin (POMC) gene and β-endorphin expression. Since, it has potent inhibitory activity on the noxious stimuli-induced POMC expression, immobilization stress seemed to dissipate the POMC gene expression process. Meanwhile, we did not find any changes in the opioid receptors' (mu-, delta- and kappa-receptor) and the cannabinoid receptors' (CB1 and CB2) expressions in the midbrain regions elicited by single or repeated stress. These results suggested that a single immobilization stress activates the descending pain modulatory system, which is mainly mediated through endorphinergic and serotonergic activation. Moreover, the tolerance of SIA induced by repeated stresses may be due to the prolonged activation of these systems induced by repeated immobilization.

This study was done to determine the effect of stress on blood glucose regulation in ICR mice. The stress was induced by the electrical foot shock-witness model. Blood glucose level was found to be increased in the electrical foot shock-induced physical stress group. Furthermore, the blood glucose levels were also elevated in the emotional stress group in both physical and emotional stress groups. The blood glucose level reached maximum 30 min after stress stimulation and returned to normal level 2 h after stress stimulation in both physical and emotional stress groups. Subsequently, we observed that intraperitoneal injection of phentolamine (an α1-adrenergic receptor antagonist), yohimbine (an α2-adrenergic receptor antagonist) or RU486 (a glucocorticoid receptor blocker) significantly inhibited blood glucose level induced by both physical and emotional stress. The results of our study suggest that physical and emotional stress increases blood glucose level via activation of adrenergic and glucocorticoid system.

We examined the antinociceptive effect of intracerebroventricularly (i.c.v.) or intrathecally (i.t.) administered of interferon-alpha (IFN-alpha) using the tail-flick analgesic test in mice. IFN-alpha administered i.c.v. but not i.t. showed an antinociceptive effect in a dose-dependent manner (0.05-5 microg). To examine the possible interaction with brain opioid system, IFN-alpha was cotreated with either beta-endorphin or morphine. Combined i.c.v. treatment of IFN-alpha (0.5 microg) with beta-endorphin (0.125 microg) caused a synergistic antinociceptive effect. And also, the synergistic interaction maintained at least for 60 min after the co-treatment of IFN-alpha and beta-endorphin. However, the combined treatment of i.t. IFN-alpha with i.c.v. beta-endorphin showed neither an additive nor a synergistic antinociceptive profile. The i.c.v. co-treatment of IFN-alpha with morphine (0.2 microg) showed an additive antinociceptive effect only. The i.t. administered IFN-alpha did not show any additive antinociceptive effect when morphine was administered i.c.v. simultaneously. Taken together, our results suggest that supraspinally co-administered IFN-alpha and beta-endorphin may produce antinociception synergistically via interaction of IFN-alpha with supraspinal beta-endorphin sensitive opioid receptors.

Visnagin, which is found in Ammi visnaga, has biological activity as a vasodilator and reduces blood pressure by inhibiting calcium influx into the cell. The present study demonstrates the anti-inflammatory effect of visnagin on lipopolysaccharide (LPS)-stimulated BV-2 microglial cells. When cells were treated with visnagin prior to LPS stimulation, production of nitric oxide and expression of iNOS were attenuated in a dose-dependent manner. Visnagin also caused a significant decrease of mRNA expression and release of TNF-α, IL-1β and IFNγ. In addition, visnagin reduced LPS-induced IL-6 and MCP-1 mRNA level. We further found that visnagin dose-dependently inhibited LPS-induced AP-1 and NF-κB luciferase activities. Taken together, our results for the first time suggest that the anti-inflammatory effect of visnagin might result from the inhibition of transcription factors, such as AP-1 and NF-κB.

Several ginsenosides (Rb1, Rb2, Rc, Rd, Re, Rf, Rg1 and Rg3) are neuroprotective and antinociceptive agents. In this study, we assessed the effects of these ginsenosides following intracerebroventricular (i.c.v.) administration on the nociceptive behaviors induced by intrathecal injection of pro-inflammatory cytokines (tumor necrosis factor-a (TNF-alpha), interleukin-1 beta (IL-1 beta), and interferon-gamma (IFN-gamma)). The ginsenosides, Rb1, Rb2, Rc, Rd, Re, Rf and Rg1, significantly attenuated the nociceptive behavior induced by TNF-alpha, IL-1 beta, and IFN-gamma injection, but ginsenoside-Rg3 did not. These results suggest that several ginsenosides may regulate the nociceptive processing induced by pro-inflammatory cytokines.

The bioassay-guided fractionation of protective agents against sepsis-induced lethality from the root cortex of Paeonia suffruticosa ANDREWS (Ranunculaceae) led to the isolation of eight known compounds: paeonol (1), 2,5-dihydroxy-4-methoxyacetophenone (2), acetovanillone (3), paeonoside (4), paeoniflorin (5), oxypaeoniflorin (6), apiopaeonoside (7), and methyl 3-hydroxy-4-methoxybenzoate (8). Among them, 3 showed the highest survival rate (100% with a dose of 30 mg/kg versus 17% for the control experiment) and reduced alanine aminotransferase level to be a half of the control value on the sepsis model induced by lipopolysaccharide/D-galactosamine.