Mechanisms of the effect of brain histamine on chronic epilepsy induced by pentylenetetrazole / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the mechanisms of histamine on chronic epilepsy induced by pentylenetetrazole (PTZ).</p><p><b>METHODS</b>To induce chemical kindling, a subconvulsive dose (35mg/kg) of PTZ was ip injected every 48 h in rats. Behavior changes were observed for 30 min after every injection of PTZ.</p><p><b>RESULT</b>Ip injection of histidine or icv injection of clobenpropit inhibited the development of kindling induced by PTZ, presenting prolonged latency for myoclonic jerks and clonic generalized seizures and depressed seizure stages in a dose-dependent manner. H(3)receptor agonist, immepip, and histidine decarboxylase, alpha-fluoromethylhistidine reversed the ameliorating effect of clobenpropit on seizure development in a dose-dependent manner.</p><p><b>CONCLUSION</b>Brain histamine plays an important role in protection against myoclonic jerks and clonic generalized clonic seizures and its action may be via H(3)receptor.</p>

Correlation between basic expression level of NMDA receptor NR1 subunit protein in hippocampus and learning ability in rats / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To investigate the relationship between basic expression level of NMDA receptor NR1 subunit protein in hippocampus and learning ability of rats.</p><p><b>METHODS</b>Using a novel-object recognition model and Morris water maze,the novel-object recognition ability and spatial memory of SD rats were ranked, and grouped as the high (top 20 %) and the low (bottom 20%), respectively. NR1 subunit protein levels in hippocampus were measured by quantitative immunoblotting with NR1 subunit specific antibody.</p><p><b>RESULT</b>The level of NR1 subunit protein in hippocampus in the high novel-object recognition ability group was 60% (P<0.01), higher than that in the low one, and in the high spatial memory group it was 45.4 % (P<0.05), higher than that in the low one, respectively.</p><p><b>CONCLUSION</b>The basic expression level of NR1 subunit protein in hippocampus is related to novel-object recognition ability and spatial memory of rats.</p>

Surface expression of NMDA receptors composed of NR1 subunit and NR2A subunit mutants with partially deleted C-terminus in HEK293 cells / 浙江大学学报·医学版

<p><b>OBJECTIVE</b>To examine the potential function of NMDA receptor NR2A subunit C-terminus in assembling and surface expression of the receptor in HEK293 cells.</p><p><b>METHODS</b>Five vectors GFP- NR2ADeltaC1- DeltaC5 were constructed for expressing N-terminally GFP-tagged NR2A with C-terminal deletion at different regions by using conventional techniques of molecular cloning. The deleted region for NR2ADeltaC1-Delta C5 was 897L-1017S, 1024D-1142P, 1149D-1347G, 1354S-1464V, and 897L-1464V. These plasmids were transfected alone or co-transfected with NR1-1a into HEK293 cells. The surface NMDA receptors were immuno-stained using rabbit antibody against GFP and Cy3 conjugated secondary antibody in living cells.</p><p><b>RESULT</b>The vectors GFP-NR2ADeltaC1-DeltaC5 were generated and all of them expressed GFP fluorescence in the transfected cells. Surface NMDA receptors were detected by immuno-labeling with anti-GFP in the cells co-transfected by NR1-1a and any one of GFP-NR2ADeltaC1-DeltaC5. However, no surface expression of NR2A proteins was found in the transfected cells with any one of these plasmids alone.</p><p><b>CONCLUSION</b>Within the region downstream from the 897L of NR2A subunit, neither a particular domain directly interacted with ER retention domain in NR1-1a C1 cassette, nor that determining ER retention of NR2A subunit itself has been found, indicating that more complicated mechanisms might exist in which the subunit assembling and targeting to plasma membrane of NMDA receptors undergo.</p>