Stephen Bunn
University of Otago, Anatomy, Faculty Member
Research Interests: Bioinformatics, Genetics, Neuroscience, Physiology, Genomics, and 18 moreComputational Biology, Data Mining in Bioinformatics, Signal Transduction, Transcriptome, Microarray, cyclic AMP, Animals, NF-kappa B, Transcriptional regulation, Peptides, ERK, Cattle, Tumor necrosis factor-alpha, Primary Cell Culture, Tnf alpha, Physiological Stress Markers, Gene Expression Regulation, and Gene expression profiling
Research Interests: Bioinformatics, Genetics, Neuroscience, Physiology, Genomics, and 18 moreComputational Biology, Data Mining in Bioinformatics, Signal Transduction, Transcriptome, Microarray, cyclic AMP, Animals, NF-kappa B, Transcriptional regulation, Peptides, ERK, Cattle, Tumor necrosis factor-alpha, Primary Cell Culture, Tnf alpha, Physiological Stress Markers, Gene Expression Regulation, and Gene expression profiling
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests:
Research Interests: Neuroscience, Neurochemistry, Calcium, Enzyme Inhibitors, Flavonoids, and 28 moreSignal Transduction, Histamine, Caffeine, Protein Kinases, Nitriles, Animals, Nicotinic Acetylcholine Receptors, Rat Brain, Phosphorylation, Biochemical, Tyrosine Hydroxylase, High Pressure Liquid Chromatography, Cattle, Time Factors, Calmodulin, Pyridines, Adrenal Gland, BIOCHEMICAL PHARMACOLOGY, Protein Phosphorylation, Protein Kinase, Gel electrophoresis, Losartan, Imidazoles, Angiotensin II, Neurosciences, Immunoblotting, Clonidine, and Adrenal Medulla
Research Interests:
Research Interests:
Research Interests: Endocrinology, Immunohistochemistry, Enzyme Inhibitors, Cell Culture, Biological Sciences, and 16 moreDopamine, Prolactin, Female, Animals, Phosphorylation, Arcuate Nucleus, Neurons, Tyrosine Hydroxylase, Enzyme, Cell nucleus, Rats, Time Dependent, Specific Activity, Time Factors, Anterior Pituitary, and Bromocriptine
1. The present report gives a detailed account of histamine-stimulated phospholipase C (PLC) activity in bovine adrenal chromaffin cells. 2. Histamine activation of H1 receptors stimulates PLC with a biphasic sensitivity to extracellular... more
1. The present report gives a detailed account of histamine-stimulated phospholipase C (PLC) activity in bovine adrenal chromaffin cells. 2. Histamine activation of H1 receptors stimulates PLC with a biphasic sensitivity to extracellular Ca2+. The initial response (the first 15 s stimulation) was not reduced by the removal of extracellular Ca2+, whereas the maintenance of PLC activity beyond this time required Ca2+ influx. 3. Phospholipase C activity in response to a 10 min incubation with histamine was inhibited by La3+ (3 mmol/L) or SKF96365 (10 mumol/L). Nifedipine (10 mumol/L), but not omega-agatoxin IVA (100 nmol/L) or omega-conotoxin GVIA (300 nmol/L), produced a partial inhibition of PLC activity. The response was also partially inhibited by a reduction in the extracellular Cl- concentration (40 mmol/L) or by the inclusion of the Cl- channel blocker N-phenylanthranilic acid (300 mumol/L). 4. Kinetic analysis of the rate of turnover of the various inositol phosphate isomers in response to histamine suggested that the inositol monophosphates were being produced from a source in addition to inositol 1,4,5-trisphosphate (Ins(1,4,5)P3) metabolism. This conclusion was supported by the differential action of pertussis toxin and neomycin on Ins(1,4,5)P3 formation compared with inositol monophosphate formation. 5. We have attempted to identify a defined role for the intracellular Ca2+ mobilized in these cells in response to histamine. After short incubations (up to 3 min), histamine was able to regulate the site-specific phosphorylation of tyrosine hydroxylase, the rate-limiting enzyme in catecholamine synthesis. This observation has important implications for a possible role for the PLC signalling pathway in controlling the rate of catecholamine biosynthesis.