Activation of protein kinase C sensitizes human VR1 to capsaicin and to moderate decreases in pH at physiological temperatures in Xenopus oocytes.

The two-electrode voltage-clamp technique was used to evaluate the effect of protein kinase C (PKC) activation on ion current flow in Xenopus laevis oocytes injected with cRNA coding for the human vanilloid receptor (VR1). In the presence of 30 nM phorbol-12,13-dibutyrate (PDBu), current evoked by an effective concentration (EC(30)) of capsaicin (CAP) was potentiated by 638+/-117% (n=8). PDBu exhibited an EC(50) of about 17+/-3 nM for this effect (n=8).

A high-throughput HERG potassium channel function assay: an old assay with a new look.

In this paper, we describe an assay using radioactive rubidium (86Rb) efflux to screen functional human ether-a go-go-related gene (HERG) K+ channels in a high-throughput screening (HTS) format. This assay offers an alternative way to examine junctional interactions between chemical compounds and HERG K+ channels. Follow-up experiments and discussions were carried out to address a variety of factors that affect potency evaluation within the Rb efflux assay.