The inhibitor constants of several inhibitors for cyclic AMP- and cyclic GMP-phosphodiesterase from various organs are compared. The inhibitors were classical theophyline, papaverine, and some of newly developed inhibitors: an imidazolidinone compound, RO20-1724, and two phthalazinol compounds, EG 467 and EG 626. Among the inhibitors tested, papaverine and EG 626 were found to be the most poten...

In this study, we characterized the signalling pathway activated by acetylcholine that encodes Ca2+ oscillations in rat duodenum myocytes. These oscillations were observed in intact myocytes after removal of external Ca2+, in permeabilized cells after abolition of the membrane potential and in the presence of heparin (an inhibitor of inositol 1,4,5-trisphosphate receptors) but were inhibited by...

The title compound, CH(6)N(3) (+)·C(7)H(4)NO(4) (-), an anhydrous guanidinium salt, shows a N-H⋯O hydrogen-bond network in which the guanidinium cation is involved in three cyclic R(2) (1)(6) hydrogen-bonding associations with separate carboxyl-ate O-atom acceptors. Further peripheral associations include a cyclic R(1) (2)(4) cation-anion inter-action, forming inter-linked undulating sheets in ...

Ab initio molecular orbital calculations at the Hartree Fock level utilizing 6-31G basis set have been performed on small cyclic peptides and peptidomimetic compounds to explore their utility as carriers of levodopa (L-3,4-dihydroxyphenylalanine) to enhance its brain bioavailability. A cyclic peptidomimetic compound with hydrophobic CH2NH backbone is suggested as possible carrier. This carrier ...

In the crystal structure of the title compound, C(14)H(23)NOSi, cyclic dimeric units are established by two very weak hydrogen bonds of the type C-H⋯N with an H⋯N distance which is only slightly shorter than the sum of the van der Waals radii of 2.75 Å. The graph-set descriptor on the unitary level is R(2) (2)(14) for the cyclic dimer.

The title compound, C(45)H(34)O(4), is the product of a tandem 'pincer' Diels-Alder reaction consisting of two consecutive [4 + 2] cyclo-additions between two 2-benzofuran units and ethyl propiolate. The mol-ecule comprises a fused hexa-cyclic system containing four five-membered rings, which are in the usual envelope conformation, and two six-membered rings. In addition, four phenyl rings are ...

In the title compound, C(3)H(5)N(2) (+)·C(2)HO(4) (-), the anions form centrosymmetric dimers through cyclic O-H⋯O hydrogen-bonding associations [graph set R(2) (2)(10)]. These dimers are then linked through a cyclic R(4) (2)(10) N-H⋯O hydrogen-bonding association involving two cations and the carboxyl O-atom acceptors of separate anions, giving chain structures extending across the (111) plane.

A cyclic naphthalene diimide (cyclic NDI, 1), carrying a benzene moiety as linker chain, was synthesized and its interaction with G-quadruplex DNAs of a-core and a-coreTT as a human telomeric DNA, c-kit and c-myc as DNA sequence at promoter region, or thrombin-binding aptamer (TBA) studied based on UV-VIS and circular dichroism (CD) spectroscopic techniques, thermal melting temperature measurem...