Kung-wong Robert Lau

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1. Intracellular pH (pHi) was measured using the fluorescent pH-sensitive dye 2',7'-bis(carboxyethyl)-5(6)-carboxyfluorescein in acini isolated from the rabbit mandibular salivary gland. 2. Stimulation of the acinar cells with acetylcholine (ACh) evoked an intracellular acidosis, the size of which was dependent on the HCO3-concentration in the bathing(More)
Previous studies have shown that, immediately after the addition of galactose or alanine to the solution bathing the mucosal surface of Necturus small intestine, there is a rapid depolarization of the electrical potential difference across the mucosal membrane (psi mc). This is followed by a repolarization of psi mc that is paralleled by an increase in the(More)
Intracellular pH (pHi) was measured in acini isolated from rabbit mandibular salivary glands using the fluorescent pH-sensitive probe 2,7-bis(carboxyethyl)-5(6)-carboxyfluorescein (BCECF). Resting pHi was estimated to be 7.13 +/- 0.01 (mean +/- SE of 29 experiments). Stimulation with acetylcholine (ACh) caused an intracellular acidosis followed by a return(More)
Intralobular striated ducts have been isolated from rabbit mandibular salivary glands and maintained in primary culture for up to 2 days. Such ducts were loaded with the Cl−-sensitive fluorescent dyeN-(ethoxycarbonylmethyl)-(6-methoxyquinolinium bromide) (MQAE) and intracellular Cl− concentration ([Cl−]i monitored using a fluorescence microscope.(More)
Ductal elements within salivary glands are responsible for modifying the electrolyte composition of primary saliva secreted by the acini. To study the mechanism and regulation of the transport processes involved requires a suitable preparation of functional ducts. To this end we have isolated intralobular ducts from rabbit mandibular salivary glands using(More)
Double-barrelled, chloride-selective microelectrodes were used to study mandibular gland acinar cells at rest and during cholinergic stimulation. At rest, intracellular chloride activity was five times the expected equilibrium activity. During sustained stimulation with acetylcholine, chloride activity fell to three times the expected equilibrium activity.(More)
When bathed on both sides with identical chloride-containing salines thein vitro preparation of the plaice intestine maintains a negative (serosa to mucosa) short-circuit current of 107±11 μA/cm2, a transepithelial potential difference of 5.5±0.6 mV (serosa negative), and a mean mucosal membrane potential of −45.4±0.6 mV. Under these conditions the(More)
1. The role of Na(+)-dependent mechanisms in regulating the intracellular pH (pHi) and free calcium concentration ([Ca2+]i) in acinar cells of the rabbit mandibular salivary gland was examined. The fluorescent dyes BCECF and Fura-2 were used to measure pHi and [Ca2+]i respectively in suspensions of isolated acini. 2. Replacement of all the extracellular Na+(More)
Exposure of Necturus small intestine to a galactose-containing perfusate that is 20% hypertonic compared to the galactose-free (control) perfusate results in a rapid depolarization of the electrical potential difference across the apical membrane, psi mc, and a decrease in the ratio of the resistance of the apical membrane to that of the basolateral(More)
Salivary gland intralobular ducts are responsible for the modification of the electrolyte composition of the primary fluid secreted by the acini. However, the intracellular messengers that regulate this and other intralobular duct cell processes have not been fully characterized. To investigate the possibility that cAMP-mobilizing agonists may be involved,(More)