Gale L. Craviso

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1. Experiments were carried out to quantify the stimulation-evoked overflow of catecholamines and purines (ATP, ADP, AMP and adenosine) from an in vitro sympathetic nerve-smooth muscle preparation of the guinea-pig vas deferens and from isolated bovine adrenal chromaffin cells. The superfused preparations were stimulated for 60 s with electrical field(More)
Electrically excitable bovine adrenal chromaffin cells were exposed to nanosecond duration electric pulses at field intensities ranging from 2 MV/m to 8 MV/m and intracellular calcium levels ([Ca(2+)](i)) monitored in real time by fluorescence imaging of cells loaded with Calcium Green. A single 4 ns, 8 MV/m pulse produced a rapid, short-lived increase in(More)
Tryptic peptide fragments of tyrosine hydroxylase isolated from 32PO4-prelabeled bovine adrenal chromaffin cells are resolved into seven phosphopeptides by reverse phase-high performance liquid chromatography. All seven of the peptides are phosphorylated on serine residues. Three of these putative phosphorylation sites, peptides 3, 5, and 6, are rapidly(More)
This study examined whether 60 Hz magnetic field (MF) exposure alters intracellular calcium levels ([Ca(2+)](i)) in isolated bovine adrenal chromaffin cells, a classic model of neural responses. [Ca(2+)](i) was monitored by fluorescence video imaging of cells loaded with the calcium indicator fluo-4 during exposures to magnetic flux densities of 0.01, 0.1,(More)
Tritiated dextromethorphan ([3H]DM) binds to two distinct sites in guinea pig brain, a high-affinity site (Kd = 13-20 nM) and a low-affinity site (Kd greater than 200 nM). Binding of [3H] DM to the high-affinity site is rapid, reversible, saturable, proportional to tissue concentration, and pH-dependent. The sites have a protein-like component, since(More)
Binding of dextromethorphan (DM) to guinea pig brain is stereoselective, since levomethorphan is 20 times weaker than DM in competing for DM sites. In general, opiate agonists and antagonists as well as their corresponding dextrorotatory isomers are weak competitors for tritiated dextromethorphan ([3H]DM) binding sites and display IC50 values in the(More)
Opiate receptors mediate the electrically evoked inhibition of the myenteric plexus-longitudinal muscle preparation of the guinea pig ileum. The electrically induced activation of the opiate receptor was produced by a prolonged simulation at 10 hertz and provides the first evidence that an endogenous opiate receptor ligand is released by nerve stimulation.(More)
Exposing chromaffin cells to a single 5 ns, 5 MV/m pulse causes Ca(2+) influx and a rapid, transient rise in intracellular calcium concentration ([Ca(2+)](i)). A comparison of responses at room temperature versus 37°C revealed no effect of temperature on the magnitude of the increase in [Ca(2+)](i). The Ca(2+) transient, however, was shortened in duration(More)
Vasoactive intestinal peptide (VIP) increased catecholamine biosynthesis in bovine adrenal chromaffin cells by 50-200%. Six related peptides produced no effects. In addition, VIP increased tyrosine hydroxylase (TH) activity measured in gel-filtered supernatants prepared from homogenates of treated cells. The hypothesis that cyclic AMP is the second(More)
Exposing bovine chromaffin cells to a single 5 ns, high-voltage (5 MV/m) electric pulse stimulates Ca2+ entry into the cells via L-type voltage-gated Ca2+ channels (VGCC), resulting in the release of catecholamine. In this study, fluorescence imaging was used to monitor nanosecond pulse-induced effects on intracellular Ca2+ level ([Ca2+]i) to investigate(More)