C-H Functionalisation for Hydrogen Isotope Exchange

The various applications of hydrogen isotopes (deuterium, D, and tritium, T) in the physical and life sciences demand a range of methods for their installation in an array of molecular architectures. In this Review, we describe recent advances in synthetic C-H functionalisation for hydrogen isotope exchange.

Anxiolytic activity of the neuroprotective peptide HLDF-6 and its effects on brain neurotransmitter systems in BALB/c and C57BL/6 mice

This study is focused on a new amide derivative of the peptide HLDF-6 (Thr-Gly-Glu-Asn-His-Arg). This hexapeptide is a fragment of Human Leukaemia Differentiation Factor (HLDF). It displays a broad range of nootropic and neuroprotective activities. We showed, for the first time, that the peptide HLDF-6-amide has high anxiolytic activity. We used 'open field' and 'elevated plus maze' tests to demonstrate anxiolytic effects of HLDF-6-amide (0.1 and 0.3 mg/kg intranasally), which were comparable to those of the reference drug diazepam (0.5 mg/kg). Five daily equipotent doses of HLDF-6-amide selectively mitigated anxiety and increased the density of NMDA receptors in the hippocampus of stress-susceptible BALB/c mice, and had no effect on stress-resilient C57BL/6 mice. The subchronic administration of HLDF-6-amide showed no effect on the density of GABAA and nicotine receptors but was accompanied by a nonselective decrease of the 5-HT2A serotonin receptor density in frontal cortex of both strains. The mechanism of the specific anxiolytic activity of HLDF-6-amide may include its action on the NMDA-glutamatergic receptor system of the hippocampus and on serotonin 5-HT2A-receptors in the prefrontal cortex. The psychotropic activity of HLDF-6-amide is promising for its introduction to medical practice as a highly effective anxiolytic medicine for mental and neurological diseases.

Cerebrovascular and neuroprotective effects of adamantane derivative

Objectives. The influence of 5-hydroxyadamantane-2-on was studied on the rats' brain blood flow and on morphological state of brain tissue under the condition of brain ischemia. The interaction of the substance with NMDA receptors was also studied. Methods. Study has been implemented using the methods of local blood flow registration by laser flowmeter, [³H]-MK-801binding, and morphological examination of the brain tissue. We used the models of global transient ischemia of the brain, occlusion of middle cerebral artery, and hypergravity ischemia of the brain. Results. Unlike memantine, antagonist of glutamatergic receptors, the 5-hydroxyadamantane-2-on does not block NMDA receptors but enhances the cerebral blood flow of rats with brain ischemia. This effect is eliminated by bicuculline. Under conditions of permanent occlusion of middle cerebral artery, 5-hydroxyadamantane-2-on has recovered compensatory regeneration in neural cells, axons, and glial cells, and the number of microcirculatory vessels was increased. 5-Hydroxyadamantane-2-on was increasing the survival rate of animals with hypergravity ischemia. Conclusions. 5-Hydroxyadamantane-2-on, an adamantane derivative, which is not NMDA receptors antagonist, demonstrates significant cerebrovascular and neuroprotective activity in conditions of brain ischemia. Presumably, the GABA-ergic system of brain vessels is involved in mechanisms of cerebrovascular and neuroprotective activity of 5-hydroxyadamantane-2-on.