The TRPA1 Agonist Cinnamaldehyde Induces the Secretion of HCO by the Porcine Colon.

A therapeutic potential of the TRPA1 channel agonist cinnamaldehyde for use in inflammatory bowel disease is emerging, but the mechanisms are unclear. Semi-quantitative qPCR of various parts of the porcine gastrointestinal tract showed that mRNA for TRPA1 was highest in the colonic mucosa. In Ussing chambers, 1 mmol·L cinnamaldehyde induced increases in short circuit current (ΔI) and conductance (ΔG) across the colon that were higher than those across the jejunum or after 1 mmol·L thymol.

A comparative study of ammonia transport across ruminal epithelia from Bos indicus crossbreds versus Bos taurus.

Absorption of ammonia from the rumen of cattle decreases nitrogen availability for fermentational protein synthesis, leading to increased competition of cattle with humans for protein and enhancing the release of toxic nitrogenous compounds into the environment. Given that differences in feeding and breeding might induce differences in ruminal ammonia transport, we compared electrophysiological, histological, and molecular biological characteristics of ruminal epithelia of Bos indicus crossbreds (Sahiwal-Mix, SWM) with those of Bos taurus (Holstein-Friesian, HF). As in HF, the stratified cornified epithelium of SWM expressed claudin 1 and 4.

Evidence for the functional involvement of members of the TRP channel family in the uptake of Na(+) and NH4 (+) by the ruminal epithelium.

Large quantities of protein are degraded in the fermentative parts of the gut to ammonia, which is absorbed, detoxified to urea, and excreted, leading to formation of nitrogenous compounds such as N2O that are associated with global warming. In ruminants, channel-mediated uptake of NH4 (+) from the rumen predominates. The molecular identity of these channels remains to be clarified.

Determination of Henry's constant, the dissociation constant, and the buffer capacity of the bicarbonate system in ruminal fluid.

Despite the clinical importance of ruminal acidosis, ruminal buffering continues to be poorly understood. In particular, the constants for the dissociation of H2CO3 and the solubility of CO2 (Henry's constant) have never been stringently determined for ruminal fluid. The pH was measured in parallel directly in the rumen and the reticulum in vivo, and in samples obtained via aspiration from 10 fistulated cows on hay- or concentrate-based diets.

Modulation of sheep ruminal urea transport by ammonia and pH.

Ruminal fermentation products such as short-chain fatty acids (SCFA) and CO2 acutely stimulate urea transport across the ruminal epithelium in vivo, whereas ammonia has inhibitory effects. Uptake and signaling pathways remain obscure. The ruminal expression of SLC14a1 (UT-B) was studied using polymerase chain reaction (PCR).

Epithelia of the ovine and bovine forestomach express basolateral maxi-anion channels permeable to the anions of short-chain fatty acids.

It has long been established that the absorption of short-chain fatty acids (SCFA) across epithelia stimulates sodium proton exchange. The apically released protons are not available as countercations for the basolateral efflux of SCFA anions and a suitable transport model is lacking. Patch clamp and microelectrode techniques were used to characterize an anion conductance expressed by cultured cells of the sheep and bovine rumen and the sheep omasum and to localize the conductance in the intact tissue.