ABSTRACT
OBJECTIVE: To observe the effect of catgut embedment at "Baihui" (GV 20), "Dazhui" (GV 14), etc. on learning-memory ability, expression of hippocampal protein kinase C interacting protein 1 (PICK 1) and glutamate receptor 2 (GluR 2) proteins and level of calcium ions, so as to explore its mechanism underlying improvement of vascular cognitive impairment. METHODS: A total of 56 male SD rats were randomly divided into sham operation, model, catgut embedment and medication groups (n=14 in each). The chronic ischemic cognitive impairment model was established by permanent occlusion of bilate-ral common carotid arteries. The catgut embedment was applied to GV 20, GV 14, "Shenshu" (BL 23) and "Xuanzhong" (GB 39), once a week, for 4 weeks. Rats of the medication group received intraperitoneal injection of monosialate tetrahexose ganglioside sodium (GM-1, 0.33 mg/kg), once daily for 4 weeks. The rats' learning-memory ability was detected by Morris water maze tasks, pathological changes of hippocampal Nissl's bodies were tested by Nissl staining. The expression levels of PICK 1 and GluR 2 proteins in the hippocampus were detected by Western bolt (WB), and the concentration of calcium ions in the hippocampus tissue was measured by Bicinchoninic acid (BCA) assay. RESULTS: After modeling, the mean escape latencies of place navigation test were significantly increased while the crossing times of target platform quadrant of space probing test notably decreased in the model, catgut embedment and medication groups compared with their own individual pre-modeling (P0.05). CONCLUSION: Catgut implantation at GV 20 etc. can effectively improve the learning-memory ability in rats with chronic ischemic cognitive impairment, which may be related to its effects in down-regulating the expression of PICK 1 and calcium ion concentration and up-regulating the expression of AMPA receptor subunit GluR 2 protein in the hippocampus.
ABSTRACT
Aim To investigate the protective effects of supercritical CO2 fluid extract(SFE)of Notoginseng a-gainst glutamate-induced PC12 cells damage and the underlying mechanism. Methods PC12 cells were dealt with glutamate to establish cell models. MTT as-say,LDH method,Hoschst 33342 staining,Fluo-3 /AM fluorescence staining and Western blot were used to observe the changes of cell viability,intracellular Ca2 + concentration and the expression of protein that interacted with C kinase l(PICK1)and glutamate re-ceptors 2 (GluR2),respectively. Results Glutamate was cytotoxic to PC12 cells with an inhibitory concen-tration 50(IC 50 )of 25 mmol·L - 1 . Pretreatment with SFE(25,50,100 mg·L-1)and FSC231(100 μmol ·L-1 )and SFE(100 mg·L-1 )+FSC231(100μmol ·L-1 )remarkablely improved cell viability,reduced LDH leakage,decreased apoptosis rate,debased intra-cellular calcium concentration,decreased the expres-sion of PICK1 ,and increased the expression of GluR2 . Conclusions SFE of Notoginseng shows protective effects against glutamate-induced PC12 cell damage, and its mechanism may be related to the inhibition of PICK1 and the increase of GluR2 protein expression.
ABSTRACT
PICK1, a PDZ domain-containing protein, is known to increase the reuptake activities of dopamine transporters by increasing their expressions on the cell surface. Here, we report a direct and functional interaction between PICK1 and dopamine D₃ receptors (D₃R), which act as autoreceptors to negatively regulate dopaminergic neurons. PICK1 colocalized with both dopamine D₂ receptor (D₂R) and D₃R in clusters but exerted different functional influences on them. The cell surface expression, agonist affinity, endocytosis, and signaling of D₂R were unaffected by the coexpression of PICK1. On the other hand, the surface expression and tolerance of D₃R were inhibited by the coexpression of PICK1. These findings show that PICK1 exerts multiple effects on D₃R functions.