Isradipine. A Potent Blocker of�L-type (Cav1.2 and Cav1.3)�Ca2+ Channels.
L-type (Cav1), voltage-gated Ca2+ channels are plasma membrane protein complexes which allow the passage of Ca2+ ions into cells following depolarization of the membrane potential. L-type channels are widely expressed in cardiac and smooth muscle where they control contraction and therefore were recognized as a therapeutic target for cardiovascular diseases.
Isradipine is a dihydropyridine that acts as a L-type, voltage-gated Ca2+ channel blocker and is used in the clinic to treat hypertension.
Isradipine inhibits L-type channels expressed in Xenopus oocytes with IC50 = 0.2 μM at a holding potential of -80 mV and the inhibition is state dependent and increases with reduced membrane hyperpolarization. Slow excitatory synaptic currents in dopaminergic neurons in slices of rat substantia nigra pars compacta and ventral tegmental area, which were evoked by a train of focally delivered electrical stimuli, were depressed by isradipine (30 nM-100 μM) in a concentration-dependent and reversible manner.
In addition, isradipine, was shown recently to be a putative effective treatment for Parkinson�s disease, by affecting particularly the excitability of certain Cav1.3 expressing dopaminergic neurons.
In a pancreatic cell line, insulin secretion triggered by 16.7 mM glucose, was completely abolished by 5 μM isradipine.
Ion Channel Modulators; Voltage - Gated Ca2+ Channel Blockers.