To investigate the kinetics of both the potentiation and desensitization of the response of ionotropic GABA receptors (GABA(A) receptors) in the presence of various compounds, we expressed receptors composed of alpha(1) and beta(1) subunits by injecting cells with the cRNAs synthesized from cloned bovine GABA(A) receptor cDNAs and measured the electrical responses of the cells electrophysiologically with or without the compounds.
Hypoxic/ischemic disruption of ionic homeostasis is a critical trigger of neuronal injury/death in the brain. There is, however, no promising strategy against such pathophysiologic change to protect the brain from hypoxic/ischemic injury. Here, we present a novel finding that activation of delta-opioid receptors (DOR) reduced anoxic Na+ influx in the mouse cortex, which was completely blocked by DOR antagonism with naltrindole.
Abnormalities in insulin/IGF-1 signaling are associated with infertility, but the molecular mechanisms are not well understood. Here we use liquid chromatography with electrospray ionization tandem mass spectrometry to show that the C. elegans insulin/FOXO pathway regulates the metabolism of locally acting lipid hormones called prostaglandins. C. elegans prostaglandins are synthesized without prostaglandin G/H synthase homologs, the targets of nonsteroidal anti-inflammatory drugs.
The Journal of Pharmacology and Experimental Therapeutics
Ginseng saponins, major active components of ginseng root used by folk medicine in the treatment of various diseases, produce multiple pharmacological responses having many effects on the central and peripheral nervous system. Specifically, ginsenoside Rg(2) has been shown to block the nicotinic acetylcholine receptors in bovine chromaffin cells. We have studied the effect of Rg(2) on different types of human neuronal nicotinic acetylcholine receptors (nAChRs), both homomeric and heteromeric, expressed in Xenopus oocytes.
Indy is a gene in Drosophila melanogaster which, when made dysfunctional, leads to an extension of the average adult life span of the organism. The present study was undertaken to clone the Indy gene-product and to establish its functional identity. We isolated a full-length Indy cDNA from a D. melanogaster cDNA library. The cDNA codes for a protein of 572 amino acids [( Drosophila Indy (drIndy)]. In its amino acid sequence, drIndy exhibits comparable similarity to the two known Na(+)-coupled dicarboxylate transporters in mammals; namely, NaDC1 (35% identity) and NaDC3 (34% identity).
Proceedings of the National Academy of Sciences of the United States of America
Increased meiotic spindle abnormalities and aneuploidy in oocytes of women of advanced maternal ages lead to elevated rates of infertility, miscarriage, and trisomic conceptions. Despite the significance of the problem, strategies to sustain oocyte quality with age have remained elusive.
The International Journal of Developmental Biology
Aneuploidy is extremely high in aged human oocytes. Its cellular origin has been elusive. Trisomy data implicate predominantly meiosis I errors in the genesis of oocyte aneuploidy. Susceptible recombination patterns increase risks for nondisjunction. Cytogenetic analyses of aged human oocytes and embryos from assisted reproduction (ART) suggest that aneuploidy primarily relates to precocious chromatid separation. Oocytes express a spindle assembly checkpoint (SAC), but do not arrest maturation in the presence of improperly attached or single, unattached chromosomes.
Obesity is associated with ovulatory disorders, decreased rates of conception, infertility, early pregnancy loss and congenital abnormalities. Poor oocyte quality and reduced IVF success have also been reported in obese women. Recent attempts to understand the mechanism by which these defects occur have focused on mitochondria, essential organelles that are critical for oocyte maturation and subsequent embryo development. The oocyte relies on maternally supplied mitochondria until the resumption of mitochondrial replication in the peri-implantation period.
We studied the effects of Chinese traditional medicine rhynchophylline (Rhy) on human ether-a-go-go related gene (HERG) channel and characterized the electrophysiological properties of Rhy's pharmacological effect on HERG channel using Xenopus oocytes. Xenopus oocytes were injected with either 23 nl (5.75 ng) HERG cRNA or 23 nl distilled water. Xenopus oocytes were randomly assigned to receive one of the following different concentrations of Rhy: (1) control, (2)10 mumol/L Rhy, (3)100 mumol/L Rhy, (4) 500 mumol/L Rhy, (5) 1 000 mumol/L Rhy, (6) 10 000 mumol/L Rhy.
Merkel cells are located in glabrous and hairy skin and in some mucosa. They are characterized by dense-core secretory granules and cytoskeletal filaments. They are attached to neighboring keratinocytes by desmosomes and contain melanosomes similar to keratinocytes. They are excitable cells in close contact with sensory nerve endings but their function is still unclear. In this review, following roles are attributed for the first time to the Merkel cells: (1) melanosomes in Merkel cells may be involved in mammalian magnetoreception.