The role of prostaglandins and the hypothalamus in thermoregulation in the lizard, Phrynocephalus przewalskii (Agamidae).

Typically, small lizards rely heavily on behavioral thermoregulation rather than physiological mechanisms to control their rates of warming and cooling. We tested the hypothesis that prostaglandins participate in mediating the cardiovascular response to heating and cooling and temperature regulating neurons in the hypothalamus of the small lizard Phrynocephalus przewalskii. In vivo and in vitro treatments, heart rates (HRs) were all found to be higher during heating than during cooling, hysteresis was distinct below 30 and 26 degrees Celsius, respectively. In vivo, as administration of COX inhibitor, there were no differences in HR between heating and cooling at any body temperature and administration of agonist prostaglandins only produced a significant effect on HR below 25 degrees Celsius. Single-unit activity was recorded extracellularly in vitro with microelectrodes, found the firing rate of the continuous unit increased 23% when the temperature of the artificial cerebrospinal fluid dropped from 30-20 degrees Celsius. We conclude that prostaglandins appear to play only a limited role in modulating heart activity in Phrynocephalus przewalskii and suggest that cold-sensitive neurons in the preoptic and anterior hypothalamus (PO/AH) are involved in thermoregulatory control during heating or cooling.

Protective effects of polysaccharide from Euphorbia kansui (Euphorbiaceae) on the swimming exercise-induced oxidative stress in mice.

The present study examined the effects of derivatives of galactosides and glucosides in a polysaccharide extract from Euphorbia kansui (Euphorbiaceae) on exercise-induced oxidative stress in mice. Exhaustive swimming exercise significantly increases the degree of lipid peroxidation in terms of malondialdehyde content and reduces the antioxidant activities of superoxide dismutase (SOD) and glutathione peroxidase (GPx). Our findings revealed that chronic oral treatment with the extract elevates enzymatic activities of SOD and GPx accompanied by a corresponding decrease in malondialdehyde. The antioxidative activities of these compounds against exercise-induced oxidative stress are correlated with various activities such as reducing the production of superoxide and hydroxyl radicals, inhibiting lipid peroxidation, enhancing antioxidative defenses, and increasing the production of SOD and GPx activity and expression in different tissues. These compounds may be involved in glycogen metabolism to meet the requirement of working skeletal muscles and act as antioxidants by terminating the chain reaction of lipid peroxidation to maintain the morphological stability of mitochondria in spinal motor neurons. These observations suggest that E. kansui has antioxidative and antifatigue properties and can be given as prophylactic and (or) therapeutic supplements for increasing antioxidant enzyme activities and preventing lipid peroxidation during strenuous exercise.

Isolation and characterization of methyl esters and derivatives from Euphorbia kansui (Euphorbiaceae) and their inhibitory effects on the human SGC-7901 cells.

PURPOSE: In this study, the inhibitory activity of the methyl esters and derivatives extracted from Euphorbia kansui (Euphorbiaceae) and their effect on apoptosis and cell cycle distribution in the human gastric cancer cell line (SGC-7901) were evaluated. METHODS: The inhibitory activity of the methyl esters and derivatives was evaluated by using trypan-blue, MTT (3-(4, 5-dimethyl thiazol-2yl) - 2, 5-diphenyltetrazolium bromide), and FCM (flow cytometry) assays. 5-fluorouracile (5-FU) was used for a positive control. RESULTS: Six new methyl esters and derivatives were extracted from the root of E. kansui. Subjecting the SGC-7901 cell line to the extract indicated that methyl ester derivatives could initiate growth inhibition and induce apoptosis in these tumor cells. The inhibitory rates as measured from trypan-blue and MTT assays were significantly increased and are comparable to those of the common antitumor agent 5-FU. In addition, the methyl ester extract effectively inhibited the proliferation of SGC-7901 cells by interfering with the progression of the cells through the G1 phase of the cell cycle. CONCLUSION: The current study indicates that methyl esters might be a promising chemopreventive and chemotherapeutic agent for treating various forms of cancer by causing apoptosis and proliferation inhibition.

Inhibitory effects of the Gentiana macrophylla (Gentianaceae) extract on rheumatoid arthritis of rats.

Acute treatment of rheumatoid rats with an extract from the roots of Gentiana macrophylla (Gentianaceae) produced a significant inhibitory effect on rheumatoid arthritis (RA). When rats were administered the Gentiana macrophylla extract orally at a daily dose of 100 mg/kg body weight, the prostaglandin E(2) (PGE(2)) levels in the inflammatory tissues, sole thickness, and ankle circumferences of feet were significantly decreased. The anti-inflammatory activity observed in Gentiana macrophylla is comparable to that observed in prednisone. These observations suggest that Gentiana macrophylla displays considerable potency in anti-inflammatory action and could be used as an anti-inflammatory agent in the control of inflammation of rheumatoid arthritis.

Toxic effect of chloromycetin on the ultrastructures of the motor neurons of the Chinese tree shrew (Tupaia belangeri).

This paper describes the toxic effects of chloromycetin on the motor neurons of the Chinese tree shrew (Tupaia belangeri chinensis) with horse radish peroxidase (HRP) as the labeling enzyme. When chloromycetin was administered orally at 2.5 mg/kg (body weight)/day for 3 days, Chinese tree shrews showed evidence of neurotoxicity. This included damage in cortical motor neuron synapses ending on neurons of the red nucleus and the ultrastructural changes in the mitochondria such as swelling of these organelles and blurring of their cristae. There was an increase of the mitochondrial matrix density and of the thickness of the synaptic membranes. These observations indicate that chloromycetin can lead to ultrastructural change of terminals of the cortical motor axons, and that Chinese tree shrews are sensitive animal model for chloromycetin neurotoxicity.