Ephedrine-caffeine mixture in wet-cold stress.

Our investigations were aimed at studying the possibility of enhancement of homeostatic processes protecting against excessive body cooling by using thermogenic drugs. We studied the influence of ephedrine (1 mg/kg) and caffeine (2.5 mg/kg) mixture in males immersed in cold water (12 degrees C) on core temperature and plasma catecholamines, cortisol, energy substrates and chosen cognitive functions in subjects without or after previous submission to short cold acclimation procedure by five repeated brief cold-water immersions. The tested drugs did not significantly influence core temperature during immersion both in acclimated and non-acclimated subjects, however, they enhanced metabolic response. There were observed faster mobilization and higher increase in energy substrates, more pronounced in acclimated subjects (free fatty acids, glucose). Tested drugs slightly improved some psychosomatic reactions. Although the results of our study suggest that a single application of ephedrine-caffeine mixture might probably support physiological mechanisms protecting against excessive body cooling when used in people in wet-cold conditions, further research is needed to confirm the clinical significance.

Total antioxidant status in the blood serum of rats exposed to N-nitroso compounds and nitric oxide synthase inhibitors.

In this study, the total antioxidant status (TAS) was assayed in the blood serum of rats pretreated per os with either N-nitrosodiethylamine (NDEA) (0.1 mg/kg b.w./day) or N-methyl-N-nitrosourea (NMU) (0.1 mg/kg b.w./day) for 30 days. The animals were also dosed per os with spermidine (SPR) (10 mg/kg b.w./day) for a first 21 day period, and Nomega)-nitro-L-arginine methyl ester (L-NAME) (10 mg/kg b.w./day) given to animals for 3 days (days 22-24), respectively. Nitric oxide synthase (NOS) inhibitor, L-NAME was found to mitigate TAS levels in the blood serum of rats pretreated with NDEA and NMU. No such changes were found in animals dosed with L-NAME only nor even with L-NAME and spermidine, respectively. Since spermidine, also known as an inhibitor of iNOS synthesis, elevated TAS levels in rats dosed with L-NAME and NDEA/NMU, the polyamine was suggested to modify the NOS/NO origin to serve the physiological level of the total anti-oxidant status in rat blood serum.

Nitrite mitigates lipid peroxidation in rat gastric mucosa.

Sodium nitrite, a nitric oxide (NO) donor in the acid pH, has been found to mitigate lipid peroxidation in rat gastric mucosa, and it elevated both Cu, Zn- and Mn-forms of the superoxide dismutase in this tissue. Putrescine, a simple polyamine of anti-oxidant properties has been shown to normalize lipid peroxidation levels in nitrite-treated animals.

Effects of nitric oxide syntase inhibitor on exercise-mediated pro- and anti-oxidative balance in rat blood plasma.

Studies showed that nitric oxide synthase (NOS) inhibitor Nomega-nitro-L-arginine methyl ester (L-NAME), enhanced anti-oxidative shifts in the blood plasma of rats subjected to exhaustive running exercise. A type of running training (continuous endurance and intermittent) before the exhaustive exercise was found to differentiate L-NAME-induced effects in rats.

Further studies on the anti-oxidative effect of putrescine in sodium nitrite-treated rats.

In recent years, dietary polyamines, including putrescine, have attracted considerable interest because of the suggestion that their presence in human diet many have some anti-oxidative properties. Therefore, studies were carried out to elucidate the anti-oxidative effect(s) of oral putrescine supplementation in rats pretreated per os with either sodium nitrite or normal saline (control). Results suggest that putrescine is an effective anti-oxidant agent, which mitigates nitrite-induced lipid peroxidation in rat liver and small intestinal mucosa.