The roles of GluN3-containing N-methyl-D-aspartate receptor in central nerve system / 浙江大学学报·医学版

The N-methyl-D-aspartate receptor (NMDAR) in central nerve system is mostly composed of GluN1 and GluN2 subunits. The classical NMDAR has been intensively studied. However, GluN3‑containing NMDAR is much less expressed and have atypical channel properties. Recently, accumulating evidences have revealed two types of GluN3‑containing NMDAR: glutamate-gated GluN1/GluN2/GluN3 NMDAR and glycine-gated GluN1/GluN3 NMDAR. The former may play important roles in regulating synapse maturation and pruning non-used synapses, and its elevated expression at the adult stage may alter synaptic reorganization in some neuropsychiatric disorders. The latter is expressed in the medial habenula and involves in control of aversion. This article reviews the recent progresses on the expression, functional properties of GluN3‑containing atypical NMDARs and the physiological and pathological relevance.

Immunohistochemistry of GluR1 subunits of AMPA receptors of rat cerebellar nerve cells

The localization of GluR1 subunits of ionotropic glutamate receptors in the glial cells and inhibitory neurons of cerebellar cortex and their association with the climbing and parallel fibers, and basket cell axons were studied. Samples of P14 and P21 rat cerebellar cortex were exposed to a specific antibody against GluR1 subunit(s) ofAMPA receptors and were examined with confocal laser scanning microscopy. GluR1 strong immunoreactivity was confined to Purkinje cell and the molecular layer. Weak GluR1 immunoreactivity was observed surrounding some Golgi cells in the granule cell layer. Intense GluR1 immunoreactivity was localized around Purkinje, basket, and stellate cells. Purkinje cells expressed strong GluR1 immunoreactivity surrounding the cell body, primary dendritic trunk and secondary and tertiary spiny den dritic branches. Marked immunofluorescent staining was also detected in the Bergmann glial fibers at the level of middle and outer third molecular layer. Positive immunofluorescence staining was also observed surrounding basket and stellate cells, and in the capillary wall. These findings suggest the specific localization of GluR1 subunits ofAMPA receptors in Bergmann glial cells, inhibitory cerebellar neurons, and the associated excitatory glutamatergic circuits formed by climbing and parallel fibers, and by the inhibitory basket cell axons.

Expression of NAD(P)H Oxidase Subunits and Their Contribution to Cardiovascular Damage in Aldosterone/Salt-Induced Hypertensive Rat

NAD(P)H oxidase plays an important role in hypertension and its complication in aldosterone-salt rat. We questioned whether NAD(P)H oxidase subunit expression and activity are modulated by aldosterone and whether this is associated with target- organ damage. Rats were infused with aldosterone (0.75 microgram/hr/day) for 6 weeks and were given 0.9% NaCl+/-losartan (30 mg/kg/day), spironolactone (200 mg/kg/ day), and apocynin (1.5 mM/L). Aldosterone-salt hypertension was prevented completely by spironolactone and modestly by losartan and apocynin. Aldosterone increased aortic NAD(P)H oxidase activity by 34% and spironolactone and losartan inhibited the activity. Aortic expression of the subunits p47(phox), gp91(phox), and p22(phox) increased in aldosterone-infused rats by 5.5, 4.7, and 3.2-fold, respectively, which was decreased completely by spironolactone and partially by losartan and apocynin. Therefore, the increased expression of NAD(P)H oxidase may contribute to cardiovascular damage in aldosterone-salt hypertension through the increased expression of each subunit.

Mechanism of recycling of post-termination ribosomal complexes in eubacteria: a new role of initiation factor 3.

Ribosome recycling is a process which dissociates the post-termination complexes (post-TC) consisting of mRNA-bound ribosomes harbouring deacylated tRNA(s). Ribosome recycling factor (RRF), and elongation factor G (EFG) participate in this crucial process to free the ribosomal subunits for a new round of translation. We discuss the over-all pathway of ribosome recycling in eubacteria with especial reference to the important role of the initiation factor 3 (IF3) in this process. Depending on the step(s) at which IF3 function is implicated, three models have been proposed. In model 1, RRF and EFG dissociate the post-TCs into the 50S and 30S subunits, mRNA and tRNA(s). In this model, IF3, which binds to the 30S subunit, merely keeps the dissociated subunits apart by its anti-association activity. In model 2, RRF and EFG separate the 50S subunit from the post-TC. IF3 then dissociates the remaining complex of mRNA, tRNA and the 30S subunit, and keeps the ribosomal subunits apart from each other. However, in model 3, both the genetic and biochemical evidence support a more active role for IF3 even at the step of dissociation of the post-TC by RRF and EFG into the 50S and 30S subunits.

Effect of early luteal phase administration of a single dose mifepristone on immunohistochemical distribution of interleukin 1 alpha (IL-1 alpha) and transforming growth factor beta 1 (TGF-beta 1) in mid-luteal phase ovary of the rhesus monkey.

A single low dose administration of a high affinity anti-progestin agent like mifepristone during the early luteal phase inhibits blastocyst implantation in human and non-human primates. Though it has been observed that luteal phase serum concentrations of estradiol and progesterone were not affected by the application of anti-nidatory dose of early luteal phase mifepristone suggesting that ovarian steroidogenic function is not compromised, it is nevertheless possible that ovarian physiology at the local tissue level is affected in this treatment schedule. In the present study, healthy, mature, proven fertile female rhesus monkeys were divided into two groups. Group 2 animals were treated with a single dose of mifepristone (2 mg/kg body weight), while group 1 animals were injected with vehicle (1:4 benzoyl benzoate: olive oil, v/v, s.c.) on day 2 post-ovulation. The morphological examination including that of vascularity, as well as, histometric determination of profiles of immunopositivity for IL-1alpha and TGF-beta1 in stromal, follicular and luteal compartments of mid-luteal phase ovaries from animals with or without a single, anti-nidatory dose of mifepristone applied on day 2 after ovulation failed to reveal any significant change between the two groups. Thus, it appears that early luteal phase administration of a single antinidatory dose of mifepristone does not affect the ovarian physiology in the treatment cycle.