The grapefruit polyphenol naringenin inhibits multiple cardiac ion channels.

Drinking fresh grapefruit juice is associated with a significant prolongation of the QT segment on the electrocardiogram (ECG) in healthy volunteers. Among the prominent polyphenols contained in citrus fruits and primarily in grapefruit, the flavonoid naringenin is known to be a blocker of the human ether-a-go-go related gene (hERG) potassium channel. Here we hypothesized that naringenin could interfere with other major ion channels shaping the cardiac ventricular action potential (AP).

In vitro ion channel profile and ex vivo cardiac electrophysiology properties of the R(-) and S(+) enantiomers of hydroxychloroquine.

Hydroxychloroquine (HCQ) is a derivative of the antimalaria drug chloroquine primarily prescribed for autoimmune diseases. Recent attempts to repurpose HCQ in the treatment of corona virus disease 2019 has raised concerns because of its propensity to prolong the QT-segment on the electrocardiogram, an effect associated with increased pro-arrhythmic risk. Since chirality can affect drug pharmacological properties, we have evaluated the functional effects of the R(-) and S(+) enantiomers of HCQ on six ion channels contributing to the cardiac action potential and on electrophysiological parameters of isolated Purkinje fibers.

Fluorescent- and tagged-protoxin II peptides: potent markers of the Na 1.7 channel pain target.

Background And Purpose: Protoxin II (ProTx II) is a high affinity gating modifier that is thought to selectively block the Na 1.7 voltage-dependent Na channel, a major therapeutic target for the control of pain. We aimed at producing ProTx II analogues entitled with novel functionalities for cell distribution studies and biochemical characterization of its Na channel targets.

Translational engagement of lysophosphatidic acid receptor 1 in skin fibrosis: from dermal fibroblasts of patients with scleroderma to tight skin 1 mouse.

Background And Purpose: Genetic deletion and pharmacological studies suggest a role for lysophosphatidic acid (LPA ) receptor in fibrosis. We investigated the therapeutic potential in systemic sclerosis (SSc) of a new orally active selective LPA receptor antagonist using dermal fibroblasts from patients and an animal model of skin fibrosis.

Experimental Approach: Dermal fibroblast and skin biopsies from systemic sclerosis patients were used.

From identification to functional characterization of cyriotoxin-1a, an antinociceptive toxin from the spider Cyriopagopus schioedtei.

Background And Purpose: The Na 1.7 channel is highly expressed in dorsal root ganglia of the sensory nervous system and plays a central role in the pain signalling process. We investigated a library prepared from original venoms of 117 different animals to identify new selective inhibitors of this target.

Direct evidence for high affinity blockade of Na1.6 channel subtype by huwentoxin-IV spider peptide, using multiscale functional approaches.

The Chinese bird spider huwentoxin-IV (HwTx-IV) is well-known to be a highly potent blocker of Na1.7 subtype of voltage-gated sodium (Na) channels, a genetically validated analgesic target, and thus promising as a potential lead molecule for the development of novel pain therapeutics. In the present study, the interaction between HwTx-IV and Na1.