Roland B Gregory

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The compound 2-aminoethyl diphenylborate (2-APB), an inhibitor of Ins(1,4,5)P(3) receptor action in some cell types, has been used to assess the role of Ins(1,4,5)P(3) receptors in the activation of store-operated Ca2+ channels (SOCs) [Ma, Patterson, van Rossum, Birnbaumer, Mikoshiba and Gill (2000) Science 287, 1647-1651]. In freshly-isolated rat(More)
Strategies which can be used to elucidate the nature of a GTP-binding regulatory protein (G-protein) involved in an intracellular pathway of interest in the complex environment of the cell are described and evaluated. A desirable strategy is considered to be one in which the first stage indicates a requirement for one or more G-proteins, provides(More)
Liver cells possess store-operated Ca2+ channels (SOCs) with a high selectivity for Ca2+ compared with Na+, and several types of intracellular messenger-activated non-selective cation channels with a lower selectivity for Ca2+ (NSCCs). The main role of SOCs is thought to be in refilling depleted endoplasmic reticulum Ca2+ stores [Cell Calcium 7 (1986) 1].(More)
The roles of the filamentous actin (F-actin) cytoskeleton and the endoplasmic reticulum (ER) in the mechanism by which store-operated Ca(2+) channels (SOCs) and other plasma-membrane Ca(2+) channels are activated in rat hepatocytes in primary culture were investigated using cytochalasin D as a probe. Inhibition of thapsigargin-induced Ca(2+) inflow by(More)
Previous studies have shown that adenophostin A is a potent initiator of the activation of SOCs (store-operated Ca2+ channels) in rat hepatocytes, and have suggested that, of the two subtypes of Ins(1,4,5)P3 receptor predominantly present in rat hepatocytes [Ins(1,4,5)P3R1 (type I receptor) and Ins(1,4,5)P3R2 (type II receptor)], Ins(1,4,5)P3R1s are(More)
The roles of a subregion of the endoplasmic reticulum (ER) and the cortical actin cytoskeleton in the mechanisms by which Ins(1,4,5)P3 induces the activation of store-operated Ca2+ channels (SOCs) in isolated rat hepatocytes were investigated. Adenophostin A, a potent agonist at Ins(1,4,5)P3 receptors, induced ER Ca2+ release and the activation of Ca2+(More)
BACKGROUND AND AIMS An increase in the cytoplasmic free Ca2+ concentration in hepatocytes as a result of the release of Ca2+ from intracellular stores and Ca2+ inflow from the extracellular space is a necessary part of the mechanism by which bile acids are moved along the bile cannaliculus by contraction of the cannaliculus. 2-Aminoethyl diphenylborate(More)
The lipophilic triphenylmethylphosphonium cation (TPMP+) has been employed to measure delta psi m, the electrical potential across the inner membrane of the mitochondria of intact hepatocytes. The present studies have examined the validity of this technique in hepatocytes exposed to graded concentrations of inhibitors of mitochondrial energy transduction.(More)
A new series of 1H-4-substituted imidazole compounds were synthesized and identified as potent and selective histamine (HA) H3 receptor ligands. These ligands establish that HA H3 antagonists exhibit stereoselective and conformational preferences in their binding to the HA H3 receptor. Structure-activity relationships were determined in vitro by HA H3(More)
The roles of a monomeric GTP-binding regulatory protein in the activation of store-activated plasma membrane Ca2+ channels and in the release of Ca2+ from the smooth endoplasmic reticulum (SER) in rat liver parenchymal cells were investigated with the use of freshly isolated rat hepatocytes and rat liver microsomes. A low concentration (approx. 130 microM(More)