Micro-extraction techniques in analytical toxicology: short review.

This paper discusses new developments in plasma micro-extraction techniques in the context of established micro-extraction and protein precipitation methodology. Simple liquid-liquid solvent extraction (LLE) of plasma with direct GC or HPLC analysis of the resulting extract has been used for many years. Butyl acetate and methyl t-butyl ether (MTBE) give efficient extraction of many drugs and metabolites from small volumes of plasma or whole blood at an appropriate pH, and form the upper layer, thus simplifying extract removal.

Dietary enrichment with omega-3 polyunsaturated fatty acids reverses age-related decreases in the GluR2 and NR2B glutamate receptor subunits in rat forebrain.

Ageing is associated with a decrease in the brain content of omega-3 polyunsaturated fatty acids (PUFA), such as eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA), and with decreased neuroplasticity. The glutamate receptor subunits GluR2 and NR2B play a significant role in forebrain synaptic plasticity. We investigated GluR2 and NR2B in the aged prefrontal cortex, hippocampus and striatum, and tested if treatment with a preparation containing EPA and DHA can reverse age-related changes.

In vivo metabolism and clearance of substance P and co-expressed tachykinins in rat striatum.

Neurons expressing the preprotachykinin A gene, which encodes the sequences of substance P, neurokinin A, neuropeptide gamma and neuropeptide K, exemplify peptide co-existence. Furthermore, there is also evidence that substance P fragments have biological activity. However, the relative contribution of each of these peptides to tachykinin signalling is still poorly understood.

Effects of sevoflurane on dopamine, glutamate and aspartate release in an in vitro model of cerebral ischaemia.

Release of excitatory amino acids and dopamine plays a central role in neuronal damage after cerebral ischaemia. In the present study, we used an in vitro model of ischaemia to investigate the effects of sevoflurane on dopamine, glutamate and aspartate efflux from rat corticostriatal slices. Slices were superfused with artificial cerebrospinal fluid at 34 degrees C and episodes of 'ischaemia' were mimicked by removal of oxygen and reduction in glucose concentration from 4 to 2 mmol litre(-1) for < or = 30 min.

Imipramine and phenelzine decrease glutamate overflow in the prefrontal cortex--a possible mechanism of neuroprotection in major depression?

Antidepressant drugs have been used for decades, but the neurobiological substrate of their efficacy is not completely understood. Although these drugs have well-established effects on monoamines, evidence is emerging that they may also affect other neurotransmitter systems. It has been shown that treatment with a wide range of antidepressants changes the binding characteristics of the N-methyl-D-aspartate type of glutamate receptor.