The 1,4-dihydropyridine (+/-)-[3H]nitrendipine reversibly binds to mitochondrial preparations from guinea-pig heart with a dissociation constant (Kd) of 593 +/- 77 nM and a maximum density of binding sites (Bmax.) of 1.75 +/- 0.27 nmol/mg of protein. This low-affinity high-capacity 1,4-dihydropyridine-binding site does not discriminate between the enantiomers of nitrendipine and is also found i...

The effects of dihydropyridine derivatives on contractile activity were examined in single fibers of frog skeletal muscles. Both nifedipine and Bay K 8644 enhanced twitch responses regardless of the presence or absence of Ca2+ without any effects on the resting membrane potential, evoked action potential and Ca2+ sensitivity of the contractile machinery. Twitch responses enhanced by Bay K 8644,...

In ethyl 5-cyano-2,6-dimethyl-4-(5-nitro-2-furyl)-1,4-dihydropyridine-3-carboxylate, C15H15N3O5, the molecules are linked into chains by a single N-H...O hydrogen bond. The molecules in diethyl 2,6-dimethyl-4-(5-nitro-2-furyl)-1,4-dihydropyridine-3,5-dicarboxylate, C17H20N2O7, are linked by a combination of one N-H...O hydrogen bond and two C-H...O hydrogen bonds into sheets built from equal nu...

In our research, new bis-α, β-unsaturated carbonyl compounds (Z2-Z4) were prepared via Claisen- Schmidt reaction, by the condensation of 2,6-dimethyl-3,5-diacetyl-1,4-dihydropyridine (Z1) with different appropriate benzaldehyde, like (benzaldehyde, m-nitro benzaldehyde and o-chloro benzaldehyde) using 10% aqueous sodium hydroxide as a base. A simple efficient method has been applied for synthes...

T he concept of proarrhythmia, the realization that antiarrhythmic drugs can occasionally drastically aggravate the very problem for which they were prescribed, is now widely appreciated and has undoubtedly lead to an overall improvement in the use of these drugs. Proarrhythmia is a particularly dangerous type of side effect: It is unpredictable, may easily escape detection, and can turn a beni...

The molecular and cellular mechanisms underlying sarcopenia, the age-related decline in muscle mass and strength, are not fully understood. It has been proposed that a reduced level of calcium ion-supply to contractile muscle proteins via excitation-contraction uncoupling leads to the muscle weakness associated with aging. The basic process of excitation-contraction uncoupling is a result of a ...

We show that peptide fragments of the dihydropyridine receptor II-III loop alter cardiac RyR (ryanodine receptor) channel activity in a cytoplasmic Ca2+-dependent manner. The peptides were AC (Thr-793-Ala-812 of the cardiac dihydropyridine receptor), AS (Thr-671-Leu-690 of the skeletal dihydropyridine receptor), and a modified AS peptide [AS(D-R18)], with an extended helical structure. The pept...

To evaluate the effects of calcium antagonists on sympathetic activity in hypertensive patients, a MEDLINE search for English language articles published between 1975 and May 1996 using the terms calcium antagonists, sympathetic nervous system, and catecholamines was conducted. Clinical studies only reporting the effects of calcium antagonists on blood pressure, heart rate, and plasma norepinep...

The binding of dihydropyridine (PN200-110) to skeletal muscle microsomes (which were 84% sealed inside-out vesicles) was not influenced by the addition of calcium or magnesium nor by addition of their chelators (EDTA or EGTA) unless the vesicles were pretreated with the calcium-magnesium ionophore A23187 and EDTA to remove entrapped cations. Separation of inside-out vesicles from right-side-out...

BACKGROUND Nilaparvata lugens, a major pest in rice-growing areas, is extremely difficult to manage. Neonicotinoids have increasingly been used in crop protection and animal health care against N. lugens. To discover new bioactive molecules and pesticides, we combined the active structure of cyanoacrylates, aromatic aldehydes, and substituted pyridyl (thiazolyl) methyl-2-substituted-methylidene...