Gene/Protein Disease Symptom Drug Enzyme Compound
Pivot Concepts:   Target Concepts:
Query: EC:3.1.30.2 (endonuclease)
 18,621 document(s) hit in 31,850,051 MEDLINE articles (0.00 seconds)

The mechanisms that lead ultimately to neuronal death in pathological ageing of the brain remain mostly unknown as in the case of Parkinson's disease where there is a progressive and selective loss of dopaminergic neurons within the substantia nigra. Dopamine-expressing PC12 cells that were neuronally differentiated by nerve growth factor treatment were chosen as a culture model in which to study some of the changes that may occur during the course of the degenerative process. They were exposed to the calcium ionophore A23187 in order to produce a sustained rise in cytoplasmic calcium, a phenomenon related to various pathological conditions. The degenerative effects of the ionophore were dose- and time-dependent. They were characterized by early fragmentation of the neurites followed ultimately by a loss in cell viability. Biochemical changes, such as a decrease in [3H]dopamine uptake and modulations of the tyrosine hydroxylase gene, were detected before macroscopic evidence of cell suffering (e.g. neurite fragmentation) could be observed. Although an ongoing degenerative process was occurring in cell somata, PC12 cells were able to recover upon ionophore withdrawal. Characteristics of apoptosis such as chromatin condensation and DNA fragmentation were detectable in a small population of dying cells. DNA fragmentation could be prevented by the endonuclease inhibitor aurintricarboxylic acid. New protein synthesis was not required, as cycloheximide failed to prevent degeneration. Taken together, these results suggest that differentiated PC12 cells react to calcium stress through a sequence of regulatory processes which appears to be independent of the apoptotic pathway.
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PMID:Morphological and molecular characterization of the response of differentiated PC12 cells to calcium stress. 791 84

Dopamine is an important neurotransmitter in the hypothalamic control of gonadotrophin secretion. Neuron response is mediated through one of five different dopamine receptors. We explored the association of D2 receptor gene polymorphisms with disorders of ovulation. We utilized a multiplex allele specific polymerase chain reaction (PCR) to detect two bi-allelic polymorphisms (four potential haplotypes) in intron 5 and exon 6 of the D2 receptor gene. A second PCR/restriction endonuclease digest was utilized to verify this. Using these assays, 185 female Hispanics (51% with known ovulatory dysfunction and 49% with normal function) were haplotyped. One allele (3) was not present in the population and there were no significant differences in remaining allele distribution between ovulatory and anovulatory patients. However, significant associations were noted between alleles and gonadotrophins and fecundity. The 4 allele had a different reproductive profile compared to the 2 allele. The 4 allele was associated with significantly higher concentrations of luteinizing hormone (LH) (means +/- SE) (19.2 +/- 2.2 versus 12.3 +/- 1.3 mIU/ml, P < 0.02) and follicle stimulating hormone (FSH) (13.2 +/- 2.0 versus 10.0 +/- 0.6 mIU/ml, P < 0.05), significantly lower concentrations of prolactin (7.9 +/- 0.8 versus 14.9 +/- 3.5 ng/ml, P < 0.02) and higher parity (1.4 +/- 0.12 versus 0.92 +/- 0.13) and lower miscarriage rates (0.89 +/- 0.1 versus 1.33 +/- 0.24, P < 0.04). We conclude that D2 receptor alleles may be associated with reproductive success through altered gonadotrophin secretion and that this effect may be independent of ovulatory function.
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PMID:Association of dopamine D2 receptor gene haplotypes with anovulation and fecundity in female Hispanics. 796 32