The 5-HT1A receptor agonist BAY x 3702 prevents staurosporine-induced apoptosis.

The 5-HT1A receptor agonist (-)-(R)-2-[4-[[(3,4-dihydro-2H-1-benzopyran-2-yl)methyl]amino]butyl]-1,2 -benzisothiazol-3(2H)-one1,1-dioxide monohydrochloride (BAY x 3702) was recently shown to have pronounced neuroprotective effects in rat models of cerebral ischemia and traumatic brain injury. In the present study we investigated the neuroprotective effects of BAY x 3702 in primary cultures of hippocampal and cortical neurons. Cell death was induced by 25 nM of the apoptosis inducing agent staurosporine and analyzed 24 h later by release of lactate dehydrogenase, formation of apoptotic bodies and DNA fragmentation. A significant neuroprotection was seen after pretreatment of the affected neurons with 50 pM to 1 microM BAY x 3702. The effects of BAY x 3702 were completely blocked by the selective 5-HT1A receptor antagonist N-(2-(4-(2-methoxyphenyl)-1-piperazinyl)ethyl)-N-(2-pyridinyl) cyclohexanecarboxamide trihydrochloride) (WAY-100635). These results indicate that low concentrations of BAY x 3702 protect cortical as well as hippocampal neurons from apoptotic cell death via a 5-HT1A receptor mediated pathway.

Importance of the intracellular domain of NR2 subunits for NMDA receptor function in vivo.

NMDA receptors, a class of glutamate-gated cation channels with high Ca2+ conductance, mediate fast transmission and plasticity of central excitatory synapses. We show here that gene-targeted mice expressing NMDA receptors without the large intracellular C-terminal domain of any one of three NR2 subunits phenotypically resemble mice made deficient in that particular subunit. Mice expressing the NR2B subunit in a C-terminally truncated form (NR2B(deltaC/deltaC) mice) die perinatally. NR2A(deltaC/deltaC) mice are viable but exhibit impaired synaptic plasticity and contextual memory. These and NR2C(deltaC/deltaC) mice display deficits in motor coordination. C-terminal truncation of NR2 subunits does not interfere with the formation of gateable receptor channels that can be synaptically activated. Thus, the phenotypes of our mutants appear to reflect defective intracellular signaling.

Tissue specific control regions of the N-methyl-D-aspartate receptor subunit NR2C promoter.

In the mouse brain, the N-methyl-D-aspartate receptor subunit NR2C (epsilon-3) is mainly detected in the cerebellar granule cells starting from the second week of postnatal life. In order to improve our understanding of molecular mechanisms of this neuron-specific, spatial and temporal gene expression, different promoter fragments were used to control indicator genes in nondifferentiated rat pheochromocytoma (PC12) cells, in human embryonal kidney (HEK293) cells and in transgenic mice. A 400 bp NR2C promoter region upstream of the transcriptional start site was identified as a basal promoter that was negatively regulated possibly by a neuron restrictive silencer element (NRSE) that is localized 664 base pairs downstream from the transcriptional start sites.

Gene structure of the murine N-methyl D-aspartate receptor subunit NR2C.

The murine N-methyl D-aspartate receptor subunit NR2C (epsilon-3) is encoded by a unique gene composed of 12 translated and three 5'-untranslated exons that spread over approximately 20 kilobases of genomic sequence. The GC-rich promoter that lacks TATA- and CAAT-positioning elements has two transcriptional start sites separated by 18 base pairs. One of these sites is located in a conserved initiator motif and, together with the first four exons, specifies the 5'-untranslated sequence of 772 nucleotides. In this sequence, two alternative splice variants were detected that show identical expression patterns in adult mouse brain. Comparison of intron positions in genes encoding different members of the glutamate receptor family confirms a close evolutionary relationship of the NR2C and NMDAR1 subunit genes.

Prognosis of urolithiasis and nephrocalcinosis in hypomagnesemia.

In 78 patients with hypomagnesemia in urolithiasis the clinical course of disease was established in relation to therapy and dynamics of changes of serum magnesium levels. Almost 70% of patients had multiple, bilateral or recurrent nephrolithiasis or nephrocalcinosis. 70% of patients had Ca-oxalate stones or bilateral nephrocalcinosis. In 52% of patients a long-term magnesium supplementation was necessary. Significant progress of nephrolithiasis and nephrocalcinosis was observed in 80% of patients with permanent hypomagnesemia and in 4% of patients with normalization of serum magnesium level. Three of 15 patients with hypomagnesemia and progress of disease were transplanted a kidney and two were treated by hemodialysis. All five patients with renal failure had bilateral nephrocalcinosis, in three of them familiar occurrence of nephrolithiasis and hypomagnesemia was found.

The evaluation of some biochemical parameters in pyridoxine-treated calcium oxalate renal stone formers.

Several serum and urinary constitutents were evaluated in 13 calcium oxalate kidney stone formers in whom according to urinary vitamin B6 excretion sufficient vitamin B6 intake before the study was suggested. The influence of 28-day Pyridoxine (Spofa) supplementation (20 mg three times daily) on these biochemical parameters was searched. Pyridoxine supplementation was followed by a significant increment in the mean values of serum uric acid; the remaining serum constitutents did not change. Urinary calcium, phosphare, magnesium, sodium, potassium, and uric acid slightly increased, urinary oxalate excretion slightly fell; there was a high variability in the changes between the individuals. No changes in the mean values of clearance of endogenous creatinine, percentage of tubular reabsorption of phosphate and urinary zinc excretion were found. It is suggested that long-term studies are necessary to search the factors influencing successful stone prevention or stone recurrency in pyridoxine-treatment patients.