[n]Cycloparaphenylenes (n = 8-13, CPPs) were synthesized, and their physical properties were systematically investigated. [8] and [12]CPPs were selectively prepared from the reaction of 4,4'-bis(trimethylstannyl)biphenyl and 4,4''-bis(trimethylstannyl)terphenyl, respectively, with Pt(cod)Cl(2) (cod = 1,5-cyclooctadiene) through square-shaped tetranuclear platinum intermediates. A mixture of [8]-[13]CPPs was prepared in good combined yields by mixing biphenyl and terphenyl precursors with platinum sources. Products were easily separated and purified by using gel permeation chromatography. In (1)H NMR spectra, the proton of the CPPs shifts to a lower field as n increased due to an anisotropic effect from the nearby PP moieties. Although the UV-vis spectra were rather insensitive to the size of the CPPs, the fluorescence spectra changed significantly in relation to their size. A larger Stokes shift was observed for the smaller CPPs. Redox properties of the CPPs were measured for the first time by using cyclic voltammetry, and the smaller CPPs had lower oxidation potentials. The results are consistent with the HOMO energies of CPPs, of which the smaller CPPs had higher energies.

For sorting peas: When a mixture of cycloparaphenylenes (CPPs) is treated with C60, [10]CPP selectively encapsulates C60 forming the shortest fullerene‐peapod, [10]CPP⊃C60 (see picture). Such complementary host–guest complexes could be useful for the size‐ and shape‐selective separation of higher fullerenes and carbon nanotubes.

No.7943 (2-[2-[4-(4-nitrobenzyloxy)phenyl]ethyl]isothiourea methanesulfonate), a selective inhibitor of the Na+/Ca2+ exchanger (NCX1), has been newly synthesized. It dose-dependently inhibited Na+i-dependent 45Ca2+ uptake and Na+i-dependent [Ca2+]i increase in cardiomyocytes, smooth muscle cells, and NCX1-transfected fibroblasts (IC50 = 1.2-2.4 microM). Inhibition was observed without prior incubation with the agent and was completely reversed by washing cells with buffer for 1 min. Interestingly, No.7943 was much less potent in inhibiting Na+o-dependent 45Ca2+ efflux and Na+o-induced [Ca2+]i decline (IC50 = >30 microM), indicating that it selectively blocks the reverse mode of Na+/Ca2+ exchange in intact cells. In cardiac sarcolemmal preparations consisting mostly of inside-out vesicles, the agent inhibited Na+i-dependent 45Ca2+ uptake and Na+o-dependent 45Ca2+ efflux with similar, but slightly lower, potencies (IC50 = 5.4-13 microM). Inhibition was noncompetitive with respect to Ca2+ and Na+ in both cells and sarcolemmal vesicles. These results suggest that No.7943 primarily acts on external exchanger site(s) other than the transport sites in intact cells, although it is able to inhibit the exchanger from both sides of the plasma membrane. No.7943 at up to 10 microM does not affect many other ion transporters nor several cardiac action potential parameters. This agent at these concentrations also did not influence either diastolic [Ca2+]i or spontaneous beating in cardiomyocytes. Furthermore, No.7943 markedly inhibited Ca2+ overloading into cardiomyocytes under the Ca2+ paradox conditions. Thus, No.7943 is not only useful as a tool with which to study the transport mechanism and physiological role of the Na+/Ca2+ exchanger but also has therapeutic potential as a selective blocker of excessive Ca2+ influx mediated via the Na+/Ca2+ exchanger under pathological conditions.

Excessive salt intake is a major risk factor for hypertension. Here we identify the role of Na(+)/Ca(2+) exchanger type 1 (NCX1) in salt-sensitive hypertension using SEA0400, a specific inhibitor of Ca(2+) entry through NCX1, and genetically engineered mice. SEA0400 lowers arterial blood pressure in salt-dependent hypertensive rat models, but not in other types of hypertensive rats or in normotensive rats. Infusion of SEA0400 into the femoral artery in salt-dependent hypertensive rats increases arterial blood flow, indicating peripheral vasodilation. SEA0400 reverses ouabain-induced cytosolic Ca(2+) elevation and vasoconstriction in arteries. Furthermore, heterozygous NCX1-deficient mice have low salt sensitivity, whereas transgenic mice that specifically express NCX1.3 in smooth muscle are hypersensitive to salt. SEA0400 lowers the blood pressure in salt-dependent hypertensive mice expressing NCX1.3, but not in SEA0400-insensitive NCX1.3 mutants. These findings indicate that salt-sensitive hypertension is triggered by Ca(2+) entry through NCX1 in arterial smooth muscle and suggest that NCX1 inhibitors might be useful therapeutically.