Protective effect of vitamin B5 (dexpanthenol) on cardiovascular damage induced by streptozocin in rats.

OBJECTIVES: This study investigated whether Dexpanthenol (DEX) improves diabetic cardiovascular function and cardiac performance by regulating total oxidant and antioxidant status. METHODS: Diabetes was induced by a single intraperitoneal injection of Streptozocin (50 mg/kg in 1 ml of saline) and treatment groups received DEX (300 mg/kg/day) for 6 weeks. Endothelium (in)dependent relaxation responses were assessed in thoracic aortic rings and coronary vasculature together with alpha receptor and voltage dependant contractile responses of aorta. Myocardial contractility has been recorded by an intra ventricular latex balloon. Total oxidant and antioxidant status were measured from the serum samples. RESULTS: Induction of diabetes resulted in an apparent body weight loss, high blood glucose, endothelial dysfunction and increased serum oxidant status. DEX supplementation restored the endothelial dysfunction, antioxidant status and body weight whereas decreasing blood glucose level. CONCLUSION: Along with the standard therapy of diabetes, DEX can be used as a safe and economical way of adjuvant therapy to diminish the burden of the disease (Tab. 3, Fig. 3, Ref. 30).

Protective effects of silymarin against doxorubicin-induced toxicity.

OBJECTIVES: The aim of the present study was to investigate the effect of silymarin on doxorubicin-induced toxicity to the rat kidney, heart, and liver. MATERIALS AND METHODS: A single dose of 10 mg/kg doxorubicin was injected intraperitoneally (ip) in the doxorubicin group. The silymarin group received silymarin (100mg/kg) every other day. In the doxorubicin + silymarin group, silymarin was injected ip at 100 mg/kg dose for 5 days before doxorubicin administration (10 mg/kg, single ip injection) and then continued daily thereafter until euthanization. On the seventh day after doxorubicin injection, eight animals from each group were decapitated and liver and heart samples were obtained. The remaining eight animals of each group continued to receive silymarin every other day, till euthanized on the twenty first day. Serum was separated for determination of superoxide dismutase (SOD), glutathione peroxidase (GSHPx), catalase (CAT), malondialdehyde (MDA), nitric oxide (NO), creatinine, urea, AST, ALT, lactate dehydrogenase (LDH) and creatinine phosphokinase (CPK) activities. Histopathological and electron microscopic examinations of heart, kidney and liver sections were also performed. RESULTS: Doxorubicin caused a significant increase in serum NO levels compared to controls. Silymarin pretreatment group lowered these. Histopathological and electron microscopic examinations of kidney, heart, and liver sections showed doxorubicin to cause myocardial and renal injury which was levv evident in silymarin treated rats. CONCLUSION(S): Results of the present study indicate that silymarin significantly protected doxorubicin-induced toxicities to the rat kidney, heart, and liver, thus suggesting its administration as a supportive care agent during anti-cancer treatment featuring doxorubicin.

Involvement of NMDA receptors and nitric oxide in the thermoregulatory effect of morphine in mice.

Morphine has long been known to have potent effects on body temperature. It has been suggested that both N-methyl-D-aspartate (NMDA) receptors and nitric oxide (NO) pathway are involved in thermoregulation and also known to play important roles in some of morphine effects. The aim of this study was therefore to investigate the contribution of NMDA receptors and NO to the thermoregulatory effect of morphine. Morphine produced a hypothermic effect, especially at the dose of 10mg/kg. Ketamine (5-40mg/kg, i.p.) and N(G)-nitro-L-arginine-methyl ester (L-NAME, 1-100mg/kg, i.p.) also produced hypothermic effects with their higher doses. At doses which themselves produced no effect on colonic temperature in mice, both ketamine (10mg/kg, i.p.) and L-NAME (10mg/kg, i.p.) enhanced the hypothermic effect of morphine (10mg/kg, i.p.). These results further support the relationship between NO and NMDA receptors and suggest a possible role of NMDA-NO pathway in the thermoregulatory effect of morphine.

Compound 48/80, a histamine-depleting agent, blocks the protective effect of morphine against electroconvulsive shock in mice.

We have shown that morphine has an anticonvulsive effect against maximal electroconvulsive shock (MES) in mice, and this effect is antagonized by histamine H1-receptor antagonists. Brain histamine is localized both in neurons and in mast cells, and morphine is known to enhance the turnover of neuronal histamine and to release histamine from mast cells. In the present experiments, compound 48/80 was injected chronically (0.5 mg/kg on day 1, 1 mg/kg on day 2, 2 mg/kg on day 3, 3 mg/kg on day 4, and 4 mg/kg on day 5, twice daily, ip) to deplete mast cell contents. Morphine (0.001-10 mg/kg, ip; N = 20) produced a dose-dependent anticonvulsive effect against MES seizure in mice with non-depleted mast cells, whereas it did not exert any anticonvulsive effect in mice with depleted mast cells. These results indicate that morphine produces its anticonvulsive effect against maximal electroconvulsive shock in mice by liberating histamine from mast cells.