Search

The article aims to identify the key chemokine receptors associated with macrophage infiltration into the vascular wall during deoxycortisosterone acetate (DOCA)/salt-induced hypertension in mice. This evaluates the impact of pharmacological inhibition of receptors on blood pressure and lukocyte accumulation. The findings highlight CCR2 as a promising therapeutic target to reduce both macrophage accumulation in the vascular wall and blood pressure in hypertension.

This study investigated the effects of the endocannabinoid, anandamide, on M1 muscarinic acetylcholine receptors (mAChRs) expressed in Chinese hamster ovary (CHO) cells. In the presence of anandamide, [3H]N-methylscopolamine ([3H]NMS) inhibition binding was characterized by Hill coefficients greater than 1 while saturation binding isotherms were characterized by a reduction in radioligand Bmax. Anandamide did not affect the potency of classic agonists, antagonists or allosteric modulators to inhibit [3H]NMS binding, indicating that the site of anandamide action did not involve receptor regions recognized by these compounds. Although the mode of binding of anandamide was reversible, the order of ligand addition was important; the inhibitory effect was greatest when anandamide was equilibrated with the receptor prior to radioligand addition, and weakest in the converse situation. Interestingly, the inhibitory potency of anandamide was reduced on pre-equilibration with non-transfected CHO cell membranes, prior to addition of M1 mAChR-transfected membranes. In phosphoinositide (PI) hydrolysis assays, anandamide significantly reduced the maximal response to acetylcholine, but at higher concentrations than those needed to fully inhibit radioligand binding. Studies utilizing a range of agonists with varying intrinsic activities showed that the inhibitory effects of anandamide on agonist function were most pronounced with the lowest efficacy agonists. These findings suggest that the mechanism of action of anandamide at the M1 mAChR involves perturbation of the receptor via the membrane in a manner that is sensitive to the conformation of the receptor (occupied versus vacant). [Copyright &y& Elsevier]

The effect of ligand pretreatment on human 5-hydroxytryptamine2C (5-HT2C) receptors was examined in CHO cells expressing high (CHO-1C7; 67±3 pmol/mg) or low (CHO-1C19; 72±10 fmol/mg) levels of the receptor. Seventy-two hours pretreatment of CHO-1C7 cells with various ligands did not affect receptor expression. Pretreatment with inverse agonists enhanced 5-HT-mediated inositol phosphate accumulation with no change in constitutive receptor activity. The enhanced agonist responsiveness was inversely correlated with the intrinsic activity of the pretreatment ligand. Seventy-two hours of pretreatment with the weak agonist, 5-methoxygramine, caused an elevation in constitutive activity but no alteration in 5-HT-mediated signaling. In CHO-1C19 cells, 24 but not 72 h of pretreatment with the inverse agonist mianserin enhanced 5-HT-mediated signaling, with no effect on basal signaling; pretreatment with 5-methoxygramine had no significant effect. These findings highlight differences in the pattern of chronic regulation of 5HT2C receptor signaling between high and low receptor expression levels in a common cellular background. [Copyright &y& Elsevier]

Purpose: To date, of all the genes studied in relation to age-related macular degeneration (AMD), the alleles of the apolipoprotein (apoE) gene have been the most consistently associated with disease. However, not all apoE studies have found an association, and among these the associations differ. The current study was conducted to investigate further the association of this gene in AMD., Methods: Three hundred twenty-two unrelated individuals with diagnosed AMD and 123 unrelated but ethnically matched control subjects were analyzed. All subjects completed a standard questionnaire and were given a fundus examination. A blood sample was collected for DNA extraction. The common allelic variants of apoE were screened through the use of polymerase chain reaction (PCR) and restriction enzyme digestion followed by statistical analysis., Results: Individuals with the epsilon3 epsilon4 genotype of apoE had an approximate halving of disease risk for late (end-stage) AMD (odds ratio [OR] 0.58, 95% confidence interval [CI] 0.34-0.98) relative to the epsilon3 epsilon3 genotype at age of ascertainment. Stratification of late AMD into atrophic and neovascular disease revealed that the greatest protective effect for the epsilon3 epsilon4 genotype was in individuals with atrophic disease (OR 0.35, 95% CI 0.13-0.92). Men with the epsilon3 epsilon4 genotype also showed almost a threefold reduction in risk of disease in late AMD (OR 0.36, 95% CI 0.16-0.82). However, individuals with late AMD and the epsilon2 epsilon3 genotype had a significantly earlier mean age of diagnosis of disease (3.4 years, P = 0.015) compared with those with the epsilon3 epsilon3 genotype, and this was most evident in women (3.9 years, P = 0.011) and in individuals with neovascular disease (4.7 years, P = 0.003)., Conclusions: The alleles of apoE appear to have a role in the etiology of AMD, with the epsilon4 allele being protective, or at the very least, delaying the age of diagnosis of disease, whereas the epsilon2 allele appears to have a modifier effect by bringing forward the mean age of disease diagnosis.