RESUMEN
Most α2-AR agonists derived from dexme-detomidine have few structure differences between them and have no selectivity for α2A/2B-AR or Gi/Gs,that can lead to the side effect of drugs.To get novel and potent α2A-AR agonists,we built the homology model for human α 2A-AR and α2B-AR to find α2A-AR agonists with higher selectivity.Compound P300-2342 and its 3 analogs sig-nificantly decreased the locomotor activity of mice(P＜0.05).Furthermore,P300-2342 and its 3 analogs inhibited the binding of[3H]rauwolscine to α 2A-AR and α 2B-AR respectively.In α2A-AR-HEK293 cells,P300-2342 decre-ased forskolinstimulatedcAMPpruductionwithoutincreas-ing cAMP pruduction,that indicated the P300-2342 acti-vating α2A-AR coupling with Gαi/o pathway without Gαs coupling.P300-2342 had no agonistic and antagonistic activities on α 2B-AR.Similar results were shown in 3 analogs of P300-2342.The docking results showed that P300-2342 formed the π-hydrogen bonds with Y394,V114 of α2A-AR,and with V93 of α2B-AR.3 analogs of P300-2342 formed several π-hydrogen bonds with V114,Y196,F390 of α 2A-AR and with V93 of α 2B-AR.We believe that these molecules can serve as leads for fur-ther optimization of α2A-AR agonists with potentially few side effects.
RESUMEN
There are differences in individual cardiovascular responses to the administration of dexmedetomidine, a highly selective α-adrenergic receptor (ADRA2A) agonist. The aim of this study was to investigate ADRA2A gene polymorphisms in the Chinese Han population and their association with the cardiovascular response to intravenous dexmedetomidine infusion. Sixty elective surgery patients of Chinese Han nationality were administered 1 µg/kg dexmedetomidine intravenously over 10 min as a premedication. ADRA2A C-1291G and A1780G polymorphism status was determined in these patients, and their relationships to changes in blood pressure and heart rate after dexmedetomidine administration were analyzed. There were neither significant differences in systolic or diastolic blood pressure changes in individuals with different A1780G and C-1291G genotypes after dexmedetomidine administration, nor in heart rates among the different A1780G genotypes. However, there were significant differences in changes in heart rates in patients with different C-1291G genotypes. There were no significant differences in the sedative effects of dexmedetomidine among different A1780G and C-1291G genotypes. Logistic regression revealed that the C-1291G polymorphism was associated with differential decreases in heart rate after intravenous infusion of dexmedetomidine. These findings indicate that the ADRA2A C-1291G polymorphism can affect heart rate changes in patients after intravenous infusion of dexmedetomidine.
RESUMEN
Objective To explore the effects and mechanism of α2A-adrenergic receptor (α2A-AR) antagonist BRL-44408 maleate on lipopolysaccharide (LPS)-induced acute lung injury (ALI) in mice. Methods Sixty male C57BL/6 mice were randomly divided into three groups (n = 20): sham group, LPS group and BRL-44408 maleate pre-treated group (BRL+LPS group). The model of ALI was replicated by intratracheally administrated of LPS (5 mg/kg), and the mice in the sham group were received an equal volume of saline. Mice in the BRL+LPS group were treated with additionally BRL-44408 maleate (5 mg/kg, i.p) at 4 hours before LPS administration. The mice were sacrificed at 6 hours and 24 hours after LPS administration in each group. Among them, 5 mice were used to collect the bronchoalveolar lavage fluid (BALF) and the other 5 mice were sacrificed for lung tissues. The levels of norepinephrine (NE), tumor necrosis factor-α (TNF-α), interleukins (IL-6, IL-10) in BALF were measured by enzyme linked immunosorbent assay (ELISA). The level of protein in BALF was measured by bicinchoninic acid (BCA) method. The histopathological changes and wet/dry (W/D) ratio of lung tissue were observed. The expression of lung phosphorylated mitogen-activated protein kinase kinase (p-MEK) and phosphorylated extracellular regulated protein kinases (p-ERK) were detected by Western Blot. Results Compared with the sham group, the lung histopathological injury was significantly aggravated, and the histopathological injury score was significantly increased, the lung W/D ratio, and total protein content, NE, TNF-α, IL-6, IL-10 in BALF, and p-MEK and p-ERK expressions were significantly increased in LPS group at 6 hours after model setup [the lung histopathological injury score: 0.70±0.04 vs. 0.14±0.13,W/D ratio: 4.79±0.15 vs. 4.35±0.17, protein content (g/L): 1.51±0.36 vs. 0.46±0.13, NE (ng/L): 85.02±11.28 vs.47.18±10.30, TNF-α (ng/L): 186.61±21.93 vs. 9.18±2.86, IL-6 (ng/L): 193.45±26.54 vs. 13.58±2.54, IL-10 (ng/L): 113.46±31.23 vs. 25.66±9.41, p-MEK/β-actin: 0.246±0.019 vs. 0.178±0.030, p-ERK/β-actin:0.257±0.013 vs. 0.175±0.014, all 1 < 0.05], and increase with time after model setup. Compared with the LPS group,BRL-44408 maleate pretreatment for 6 hours could significantly improve the degree of lung injury and reduce the lung histopathological injury score (0.61±0.05 vs. 0.70±0.04), reduce lung W/D weight ratio (4.51±0.22 vs. 4.79±0.15);the expression of NE, TNF-α, IL-6 in BALF were inhibited [NE (ng/L): 55.77±15.86 vs. 85.02±11.28, TNF-α (ng/L): 54.79±12.68 vs. 186.61±21.93, IL-6 (ng/L): 67.66±20.08 vs. 193.45±26.54], in addition, the up-regulation of p-MEK, p-ERK were significantly inhibited (p-MEK/β-actin: 0.204±0.008 vs. 0.246±0.019, p-ERK/β-actin:0.186±0.024 vs. 0.257±0.013), with statistically significant differences (all 1 < 0.05). The protein content and the expression of IL-10 in BALF showed no significant difference. Conclusion α2A-AR blocker BRL-44408 maleate could alleviate endogenous ALI induced by LPS in mice by inhibiting the MEK/ERK pathway.