CaV1.2 calcium channel assays for preclinical drug studies

Why conduct a CaV1.2 calcium channel assay?

The voltage gated cardiac calcium ion channel CaV1.2, encoded by the CACNA1C gene, is a key component of the shape of the plateau phase and is highly implicated in the repolarization process of the action potential. When the CaV1.2 calcium channel cannot adequately conduct electrical current across the cell membrane, this may result in undesirable cardiovascular side effects leading to life threatening arrythmias called Torsade de Pointe.

CaV1.2 calcium assays & preclinical studies

At a preclinical stage, CaV1.2 calcium channel assays aim to identify potential inhibitory effects early in the drug discovery process. A number of clinically successful drugs have had the tendency to inhibit the Cav1.2 calcium channel, entailing a concomitant risk of sudden death. As a result, a large number of drugs have been withdrawn from the market or during late stage clinical trials due to cardiotoxic effects. 

What we measure

A pharmacological reduction of the calcium current has been shown to shorten the repolarization process and decrease the contractility. This makes the human CaV1.2 calcium channel a major target for the cardiac safety assessment.

Mutation LQT8: the gain-of-function mutation in the CACNA1C gene may result in a markedly prolonged action potential duration causing a rare congenital arrhythmia: the long QT syndrome LQT8 (Timothy syndrome).

Why choose PhysioStim for your calcium channel assay ?

The experts at PhysioStim respect all ICH guidelines to perform screening and GLP-compliant studies. Moreover, our stimulation protocol is designed to make sure you get the highest value out of your assay:

Technique

  • Conventional manual Patch Clamp
  • 3 or 4 increasing concentrations of assay compound tested independently

Study model

  • Chinese Hamster Ovary CHO cells
  • 6 treated cells per concentration tested and 6 control cells (as basic design protocol but can be adapted)

Measured parameters

  • Amplitude of the peak current upon depolarization to 0 mV (pA)
  • Amplitude of the base current at –80 mV (pA)
  • Inhibition of CaV1.2 peak current amplitude (%)

Stimulation protocol

Cav1.2 calcium channel assay stimulation protocol
Cav1.2 calcium channel assay result curve

Typical effects of nifedipine on CaV1.2 calcium currents recorded from CHO cells

Results

  • ion current inhibition measurement
  • IC50 value

Ref­er­ence com­pounds or pos­i­tive con­trols

REFERENCE COM­POUNDS IC50
Ver­a­pamil 3.4 µM
Nifedip­ine 2.8 nM
Dil­ti­azem 7.7 µM

Advice from our expert scientists

In order to confirm results during Cav1.2 calcium channel assays and the impact on cardiac contractility or ECG, PhysioStim recommends completing your Cav1.2 calcium channel assay with additional tests:

Need help with your preclinical safety assays ?

Don’t hesitate to contact us