Short-chain fatty acids (SCFAs) are the major anions in the colonic lumen. Experiments studied how intracellular pH (pHi) of isolated colonocytes was affected by exposure to SCFAs normally found in the colon. Isolated crypt fragments were loaded with SNARF-1 (a fluorescent dye with pH-sensitive excitation and emission spectra) and studied in a digital imaging microscope. Intracellular pH was me...

We examined pH regulation in two chemosensitive areas of the brain, the retrotrapezoid nucleus (RTN) and the nucleus tractus solitarius (NTS), to identify the proton transporters involved in regulation of intracellular pH (pHi) in medullary glia. Transverse brain slices from young rats [postnatal day 8 (P8) to P20] were loaded with the pH-sensitive probe 2',7'-bis (2-carboxyethyl)-5,6-carboxyfl...

Methadone is a synthetic analgesic widely used in methadone maintenance programmes. Methadone (MTD) is generally administered orally as a racemate, however the therapeutic effect is almost exclusively mediated by the (R)-enantiomer since its affinity for the μ-opioid receptor and its analgesic effect is up to 8 and 50 times, respectively, greater than for the (S)-enantiomer. Because of importan...

Maintenance of an acidic intralysosomal compartment may be relevant to multiple aspects of neutrophil function. The effect of lysosomal alkalinization on the neutrophil respiratory burst was studied by measuring cytochrome c reduction in response to soluble stimuli in the presence of lysosomotropic weak bases. The weak bases chloroquine, ammonium chloride, methylamine, and clindamycin all raise...

Alendronate, an oral bisphosphonate (e.g., Fosamax(®)), is effective in the treatment of osteoporosis, and the Fosamax(®) package insert advises that the bioavailability is reduced when taken with mineral water containing high levels of metal cations (Ca(2+), Mg(2+), etc.). However, standards regarding the water used when taking alendronate are unclear. In this study, the influence of mineral w...

The astrocyte-neuronal lactate-shuttle hypothesis posits that lactate released from astrocytes into the extracellular space is metabolized by neurons. The lactate released should alter extracellular pH (pHe), and changes in pH in central chemosensory regions of the brainstem stimulate ventilation. Therefore, we assessed the impact of disrupting the lactate shuttle by administering 100 microM al...

A sustained high voltage-activated (HVA), nifedipine- and cadmium-sensitive calcium current and a sustained calcium action potential (AP) were recorded from horizontal cells isolated from catfish retina. pH indicator dyes showed that superfusion with NH4Cl alkalinized these cells and that washout of NH4Cl or superfusion with Na-acetate acidified them. HVA current was slightly enhanced during su...

OBJECTIVE To evaluate at which pH level various local anesthetics precipitate, and to confirm which combination of corticosteroid and local anesthetic crystallizes. METHODS Each of ropivacaine-HCl, bupivacaine-HCl, and lidocaine-HCl was mixed with 4 different concentrations of NaOH solutions. Also, each of the three local anesthetics was mixed with the same volume of 3 corticosteroid solution...

The gut contents of larval mosquitoes are alkalinized by the anterior midgut and reacidified by the posterior midgut. In the present study the cellular mechanisms of reacidification were studied in isolated, perfused posterior midgut by measuring the transepithelial voltage (V(te)) and the rate of acid secretion as indicated by the color change of m-cresol purple during intervals of perfusion s...

We have previously demonstrated that the airway serous cell line Calu-3 employs a number of pH regulatory mechanisms required for bicarbonate secretion by these cells. The aim of the present study was to investigate the pH regulatory mechanisms of serous cells of freshly isolated submucosal glands (SMG). Porcine SMG were dissected out of pig tracheas obtained from a local slaughterhouse. Single...