C/EBPα represses slow myosin heavy chain 2 gene expression in developing avian myotubes.

Background: The CCAAT/enhancer binding proteins (C/EBP) comprise a family of transcription factors that regulate many cellular processes. Little is known of their function during embryonic and fetal myogenesis. Slow myosin heavy chain 2 (MyHC2) is a marker of the slow avian skeletal muscle fiber type, and slow MyHC2 gene regulation involves molecular pathways that lead to muscle fiber type diversification.

Direct electrical stimulation of myogenic cultures for analysis of muscle fiber type control.

Secondary skeletal muscle fiber phenotype is dependent upon depolarization from motor neuron innervation. To study the effects of depolarization on muscle fiber type development, several in vivo and in vitro model systems exist. We have developed a relatively simple-to-use in vitro model system in which differentiated muscle cells are directly electrically stimulated at precise frequencies.

Heteromeric TASK-1/TASK-3 is the major oxygen-sensitive background K+ channel in rat carotid body glomus cells.

Carotid body (CB) glomus cells from rat express a TASK-like background K+ channel that is believed to play a critical role in the regulation of excitability and hypoxia-induced increase in respiration. Here we studied the kinetic behaviour of single channel openings from rat CB cells to determine the molecular identity of the 'TASK-like' K+ channels. In outside-out patches, the TASK-like background K+ channel in CB cells was inhibited >90% by a reduction of pH(o) from 7.

Pore dilation occurs in TRPA1 but not in TRPM8 channels.

Abundantly expressed in pain-sensing neurons, TRPV1, TRPA1 and TRPM8 are major cellular sensors of thermal, chemical and mechanical stimuli. The function of these ion channels has been attributed to their selective permeation of small cations (e.g.

Control of the single channel conductance of K2P10.1 (TREK-2) by the amino-terminus: role of alternative translation initiation.

TREK-2 expressed in mammalian cells exhibits small ( approximately 52 pS) and large ( approximately 220 pS) unitary conductance levels. Here we tested the role of the N-terminus (69 amino acids long) in the control of the unitary conductance, and role of the alternative translation initiation as a mechanism that produces isoforms of TREK-2 that show different conductance levels. Deletion of the first half (Delta1-36) of the N-terminus had no effect.

Cutaneous nociception evoked by 15-delta PGJ2 via activation of ion channel TRPA1.

Background: A number of prostaglandins (PGs) sensitize dorsal root ganglion (DRG) neurons and contribute to inflammatory hyperalgesia by signaling through specific G protein-coupled receptors (GPCRs). One mechanism whereby PGs sensitize these neurons is through modulation of "thermoTRPs," a subset of ion channels activated by temperature belonging to the Transient Receptor Potential ion channel superfamily. Acrid, electrophilic chemicals including cinnamaldehyde (CA) and allyl isothiocyanate (AITC), derivatives of cinnamon and mustard oil respectively, activate thermoTRP member TRPA1 via direct modification of channel cysteine residues.

Inhibition of transient receptor potential A1 channel by phosphatidylinositol-4,5-bisphosphate.

Membrane phosphatidylinositol-4,5-bisphosphate (PIP2) is critical for the function of many transient receptor potential (TRP) ion channels. The role of PIP2 in TRPA1 function is not well known. The effect of PIP2 on TRPA1 was investigated by direct application of PIP2 and by using polylysine and PIP2 antibody that sequester PIP2.

Requirement of a soluble intracellular factor for activation of transient receptor potential A1 by pungent chemicals: role of inorganic polyphosphates.

Pungent chemicals such as allyl isothiocyanate (AITC), cinnamaldehyde, and allicin, produce nociceptive sensation by directly activating transient receptor potential A1 (TRPA1) expressed in sensory afferent neurons. In this study, we found that pungent chemicals added to the pipette or bath solution easily activated TRPA1 in cell-attached patches but failed to do so in inside-out or outside-out patches. Thus, a soluble cytosolic factor was required to activate TRPA1.