During neuromuscular synapse development, the degradation rate of ACh receptors (AChRs) accumulated in the synaptic portion of the muscle membrane is drastically reduced under neural control, their half-life t1/2 increasing from 1 d to about 12 d. Recent evidence suggests that the metabolic stability of synaptic AChRs is mediated by the muscle activity induced by the nerve. We have now investig...

An increase in cytoplasmic calcium is an early event in hormone (cytokinin)-induced vegetative bud formation in the moss Physcomitrella patens. Whole cell and calcium transport studies have implicated 1,4-dihydropyridine-sensitive calcium channels in this increase in cellular calcium. To understand the molecular nature of the dihydropyridine-sensitive calcium channel, we have established condit...

To identify the function of triadin in skeletal muscle, adenovirus-mediated overexpression of Trisk 95 or Trisk 51, the two major skeletal muscle isoforms, was induced in rat skeletal muscle primary cultures, and the physiological behavior of the modified cells was analyzed. Overexpression did not modify the expression level of their protein partners ryanodine receptor, dihydropyridine receptor...

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 ...