Anti-NPPB monoclonal antibody, clone 9E6C5D22

Currents through anion channels in the plasma membrane of Lilium longiflorum pollen grain protoplasts were studied under conditions of symmetrical anionic concentrations by means of patch-clamp whole-cell configuration. With Cl--based intra-and extracellular solutions, three outward-rectifying anion conductances, I-Cl1, I-Cl2 and I-Cl3, were identified. These three activities were discriminated by differential rundown behaviour and sensitivity to 5-nitro-2-(phenylpropylamino)-benzoate (NPPB), which could not be attributed to one or more channel types. All shared strong outward rectification, activated instantaneously and displayed a slow time-dependent activation for positive potentials. All showed modulation by intracellular calcium ([Ca2+](in)), increasing intensity from 6.04 nM up to 0.5 mM (I-Cl1), or reaching a maximum value with 8.50 mu M (I-Cl2 and I-Cl3). After rundown, the anionic currents measured using NO3--based solutions were indistinguishable, indicating that the permeabilities of the channels for Cl- and NO3- are similar. Additionally, unitary anionic currents were measured from outside-out excised patches, confirming the presence of individual anionic channels. This study shows for the first time the presence of a large anionic conductance across the membrane of pollen protoplasts, resulting from the presence of Ca2+-regulated channels. A similar conductance was also found in germinated pollen. We hypothesize that these putative channels may be responsible for the large anionic fluxes previously detected by means of self-referencing vibrating probes.

Brain natriuretic peptide (BNP/NPPB) is a member of the natriuretic family involved in the regulation of blood pressure and blood volume as well as lipolysis control in human fat cells. Thus BNP may play a role in energy metabolism and metabolic diseases. We therefore assessed the association between the BNP promoter T-381C polymorphism and risk of type 2 diabetes and metabolic and BNP expression traits in several population samples. In French population-based samples (n = 3216), we found that individuals bearing the -381CC genotype had lower (P = 0.005) fasting glucose levels than -381TC or -381TT individuals. Moreover, the -381CC genotype vias less frequent in individuals with type 2 diabetes (n = 280, 13.6%) or with impaired fasting glucose (n = 248, 12.9%) compared with normoglycaemic individuals (n = 2485, 17.8%). The adjusted odds ratio (OR) (95% CI) of type 2 diabetes for -381CC individuals was 0.69 (0.47-1.00), P = 0.05, when compared with -381T allele bearers. We replicated this association in four additional case-control studies for type 2 diabetes. The overall OR (95% CI) of type 2 diabetes was 0.85 (0.76-0.96), P = 0.008, (under a recessive model) (3593 cases and 6646 controls in total). We also found that the -381C allele was associated with higher plasma BNP concentrations (P = 0.015, n = 634) and higher BNP promoter activity in reporter gene assays. Collectively, these data suggest that relatively high BNP expression may protect against type 2 diabetes in humans.