Effect of carbon monoxide on dopamine and glutamate uptake and cGMP levels in rat brain.

After the recognition of nitric oxide (NO) as a messenger molecule in the nervous system, carbon monoxide (CO) has received attention with similar properties. The present study aims to elucidate the effects of CO on synaptosomal dopamine ((3)H-DA) and glutamate ((3)H-Glu) uptake and on cGMP levels; possible interaction between NO and CO systems was also evaluated. Our results provide evidence for the inhibition of DA and Glu uptake by CO in a time-, dose-, and temperature-dependent manner in rat striatum and hippocampus, respectively; the inhibition observed was sexually dimorphic with more pronounced effects in females.

The effect of octreotide on kainate-induced wet dog shakes and seizure activity in male and female rats.

Systemic kainic acid (KA) administration to rats triggers wet dog shakes (WDS) followed by epileptic seizures. Although WDS are often associated with the occurrence of seizures, we have recently shown that following nitric oxide (NO) synthesis inhibition, the number of WDS decreased; subsequently the onset of seizure activity was shortened, and the number of convulsions was increased. Somatostatin (SS), whose release appears to be controlled by NO, inhibits seizure activity.

Are attractors 'strange', or is life more complicated than the simple laws of physics?

Interesting and intriguing questions involve complex systems whose properties cannot be explained fully by reductionist approaches. Last century was dominated by physics, and applying the simple laws of physics to biology appeared to be a practical solution to understand living organisms. However, although some attributes of living organisms involve physico-chemical properties, the genetic program and evolutionary history of complex biological systems make them unique and unpredictable.

Sex differences in brain and behavior: emphasis on nicotine, nitric oxide and place learning.

Although males and females are unmistakably different, the recognition of sex as a key variable in science and medicine is considered a revolution in some circles. Sex differences transcend reproductive functions, are evident in the structural and functional organization of the brain, and are reflected in group differences in cognitive abilities and behavior. Males and females have different neural organizational patterns for information processing and different strategies in problem solving.

Nitric oxide synthetase inhibition hinders facilitation of active avoidance learning by nicotine in rats.

Nicotine produces dose-dependent enhancement of performance in an active avoidance test, and also increases the levels of NO2- and NO3-, which are stable metabolites of nitric oxide (NO), in various brain regions of rats. On the basis of these two observations, we hypothesized that the beneficial effect of nicotine on learning could result from increased NO in relevant brain regions. We therefore tested active avoidance performance in rats given L-Nomega-nitroarginine (L-NA) to inhibit NO synthetase (NOS) prior to nicotine administration.

The effects of melatonin on the antioxidant systems in experimental spinal injury.

Melatonin has been recently shown by various in-vivo and in-vitro studies to exert potent neutralising effects on hydroxyl radicals, stimulate glutathione peroxidase (GSH-Px) activity, and protect catalase (CAT) from the destructive activity of hydroxyl radicals in neural tissue. We aimed to investigate the possible effects of pharmacological dose of melatonin on some of the antioxidant defence systems in an in-vivo study of experimental spinal injury. Seven groups of adult male Sprague Dawley rats were used in the following scheme: Group I: Naive (n = 6), Group II: Lesion (n = 8), Group III: Melatonin (n = 5), Group IV: Melatonin + Lesion (n = 8), Group V: Placebo + Lesion (n = 5), Group VI: Sham operation (n = 5), and Group VII: Placebo (n = 5).

Intersession interval affects performance in the Morris Water Maze.

We have recently reported an effect that shows a sexually dimorphic difference in cognitive style rather than ability. The preparation for potentially producing this proximal perceptual style effect is one where rats are first given 4-trial daily acquisition sessions for 12 days with the platform always in the same position, but sometimes visible (perceptual, "look-out" condition) and sometimes hidden (conceptual, "navigational" condition). On the first, probe trial of the 13th day, the platform's position is shifted to a point very close (proximal) to the rat's starting position, and made visible.