L-type calcium channel antagonists and suppression of expression of plasminogen receptors: is the missing link the L-type calcium channel?

摘要

Several types of voltage-dependent Ca~(2+) channels were reported in many excitable and nonexcitable cell types, including the L-, T-, P-, N-, and Q-types; the isradipine sensitive steady-state resting R-type; and the nifedipine resistant R-type channels. The presence of some of these voltage-dependent Ca~(2+) channel types depends on cell origin. Among these channels, the L-type is the most studied channel because of the large number of Ca~(2+) blockers that affect its function. Historically, calcium channel antagonists were developed before the discovery of the L-type Ca~(2+) channel. These Ca~(2+) channel antagonists are divided into 3 classes of drugs: benzothiazepines (such as verapamil), dihydropyri-dines (such as amlodipine), and phenylalkylamines (such as diltiazem). The 3 classes of L-type Ca~(2+) channel antagonists have different relative selectivity for cardiac and vascular tissues. Their effects depend on the frequency of channel opening and where they physically bind on the channel.