Combinatorial Chemistry & High Throughput Screening - Volume 12, Issue 1, 2009

Ion channel proteins are fascinating molecules that play key roles in many physiological processes. In fact, no mammalian cell type has been identified which does not express a complement of ion channel proteins. However, while all cell types express ion channels, the specific role these channels play can vary significantly. In excitable cells such as neurons, skeletal muscle and heart, ion channels act as molecular switches Read More

Ion channels are intimately involved in virtually every physiological process of consequence in humans. Their importance is underscored by the identification of numerous “channelopathies”, human diseases caused by ion channel mutations. Ion Channels have consequently been viewed as fertile ground for drug discovery and, indeed, they represent one of the largest target classes for current medicines. The future prospec Read More

Ion channel dysfunction is known to underlie several acute and chronic disorders and, therefore, ion channels have gained increased interest as drug targets. During the past decade, ion channel screening platforms have surfaced that enable high throughput drug screening from a more functional perspective. These two factors taken together have further inspired the development of more refined screening platforms, su Read More

Voltage-clamp techniques are typically used to study the plasma membrane proteins, such as ion channels and transporters that control bioelectrical signals. Many of these proteins have been cloned and can now be studied as potential targets for drug development. The two approaches most commonly used for heterologous expression of cloned ion channels and transporters involve either transfection of the Read More

Planar chip technology has strongly facilitated the progress towards fully automated electrophysiological systems that, in contrast to the traditional patch clamp technology, have the capability of parallel compound testing. The throughput has been increased from testing below 10 compounds per day to a realized capacity approaching high throughput levels. Many pharmaceutical companies have implemented automated plan Read More

Hyperpolarization- and Cyclic Nucleotide-gated (HCN) channels are a family of six transmembrane domain, single pore-loop, hyperpolarization activated, non-selective cation channels. The HCN family consists of four members (HCN1-4). HCN channels represent the molecular correlates of Ih (also known as ‘funny’ If and ‘queer’ Iq), a hyperpolarization- activated current best known for its role in controlling heart rate and in t Read More

To facilitate automated patch clamp measurements of ion channels in cells, the development of an all-glass Chiptip pipette is reported that may be combined with the previously described Flip-the-Tip technology. A single measurement requires less than 50 cells, and the addition of drugs for screening can be limited to very low volumes down to 1 μL. This apparatus is suitable for the study small cells, subcellular organelles and bacteria.

The conventional patch clamp has long been considered the best approach for studying ion channel function and pharmacology. However, its low throughput has been a major hurdle to overcome for ion channel drug discovery. The recent emergence of higher throughput, automated patch clamp technology begins to break this bottleneck by providing medicinal chemists with high-quality, information-rich data in a more time Read More

The tractability of ion channels as drug targets has been significantly improved by the advent of planar array electrophysiology platforms which have dramatically increased the capacity for electrophysiological profiling of lead series compounds. However, the data quality and through-put obtained with these platforms is critically dependent on the robustness of the expression reagent being used. The generation of high qu Read More

Voltage dependent sodium channels are widely recognized as valuable targets for the development of therapeutic interventions for neuroexcitatory disorders such as epilepsy and pain as well as cardiac arrhythmias. An ongoing challenge for sodium channel drug discovery is the ability to readily evaluate state dependent interactions, which are known to underlie inhibition by many clinically used local anesthetic, antiepileptic and a Read More

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