Interactions of analogs of the 1,4-dihydropyridine tiamdipine in cardiac and smooth muscle

1,4-Dihydropyridine: A Dependable Heterocyclic Ring with the Promising and the Most Anticipable Therapeutic Effects

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Nowadays, heterocyclic compounds act as a scaffold and are the backbone of medicinal chemistry. Among all of the heterocyclic scaffolds, 1,4-Dihydropyridine (1,4-DHP) is one of the most important heterocyclic rings that possess prominent therapeutic effects in a very versatile manner and plays an important role in synthetic, medicinal, and bioorganic chemistry. The main aim of the study is to review and encompass relevant studies related to 1,4-DHP and excellent therapeutic benefits of its derivatives. An extensive review of Pubmed-Medline, Embase and Lancet’s published articles was done to find all relevant studies on the activity of 1,4-DHP and its derivatives. 1,4-DHP is a potent Voltage-Gated Calcium Channel (VGCC) antagonist derivative which acts as an anti-hypertensive, anti- anginal, anti-tumor, anti-inflammatory, anti-tubercular, anti-cancer, anti-hyperplasia, anti-mutagenic, anti-dyslipidemic, and anti-ulcer agent. From the inferences of the study, it can be concluded that the basic nucleus, 1,4-DHP which is a voltage-gated calcium ion channel blocker, acts as a base for its derivatives that possess different important therapeutic effects. There is a need of further research of this basic nucleus as it is a multifunctional moiety, on which addition of different groups can yield a better drug for its other activities such as anti-convulsant, anti-oxidant, anti-mutagenic, and anti-microbial. This review would be significant for further researches in the development of several kinds of drugs by representing successful matrix for the medicinal agents.

Ca2+ channel blocking activity of lacidipine and amlodipine in A7r5 vascular smooth muscle cells

Inhibition of the K(+)-stimulated increase in cytosolic free Ca2+ by a series of 1,4-dihydropyridines was evaluated in A7r5 vascular smooth muscle cells loaded with the fluorescent Ca2+ indicator fura-2 acetoxymethyl ester. The IC50 of the drugs, added to suspended cells 3 min before 150 mM KCl, gave the following order of potency: lacidipine (2.76 nM) > nitrendipine (3.81 nM) > amlodipine (4.56 nM) > nifedipine (10.08 nM). A7r5 cells were also exposed to the 1,4-dihydropyridines, at their IC50, for 25 min, and then repeated washout cycles were performed before adding KCl. The Ca2+ channel blocking activity of nifedipine and nitrendipine gradually diminished, disappearing after four washout cycles 25, 55, 115 and 175 min after drug treatment. Amlodipine and lacidipine displayed slow onset and offset of antagonism, their activity becoming stronger with time, in spite of the repeated washes. [3H]Lacidipine was avidly and promptly entrapped in A7r5 cells and was not removed by washout. However, its potency as a Ca2+ channel blocker was not directly related to the amount of drug locked in the cell since it increased with time, indicating that lacidipine binds to the lipid bilayer of the cell membrane and then gradually diffuses towards a specific binding site. This model can, therefore, predict the Ca2+ blocking properties of 1,4-dihydropyridines with slow onset and offset of antagonism and could be employed to evaluate compounds selective for vascular smooth muscle.