dihydroergotoxine and Neuroblastoma

The effect of dihydroergocristine on energy metabolism was studied in the isolated perfused rat brain affected by ischemia and in cultivated C-1300 neuroblastoma cells deprived of oxygen and glucose. Creatine phosphate, ATP, ADP, AMP, glucose, glucose-6-phosphate, fructose-6-phosphate, fructose-1,6-diphosphate, pyruvate, and lactate were measured enzymatically. After a perfusion period of 30 min, the cortex of the isolated perfused rat brain exhibited an energy state not different from that in vivo. Dihydroergocristine added to the perfusion medium (5 mumol/L) did not influence these substrate levels under normal perfusion conditions. However, this drug was able to retard the breakdown of high-energy phosphates during ischemia and to accelerate the restoration of the energy state during the postischemic reperfusion period. The perfusion rate was not changed by the drug, and therefore it was assumed that dihydroergocristine could act directly on cell metabolism. This view was supported by the results obtained from experiments using cultivated N-2a neuroblastoma cells. These cells were incubated in a buffered salt solution deprived of glucose and oxygen for 15 min. Under these conditions, dihydroergocristine (2 mumol/L) added to the incubation medium caused changes in the concentrations or the high-energy phosphates similar to those in the isolated brain preparation: It increased the ATP concentration and decreased the ADP concentration significantly.

Topics: Adenosine Triphosphate; Animals; Brain; Brain Ischemia; Cells, Cultured; Dihydroergotoxine; Electroencephalography; Energy Metabolism; Glucose; Neuroblastoma; Oxygen Consumption; Rats

[3H]Dihydroergocryptine ([3H]DHE) was shown to bind to sites in membranes from neuroblastoma X glioma hybrid cells (NG 108-15) that had the characteristics expected of alpha-adrenergic receptors. The binding was saturable with 0.3 pmol [3H]DHE bound per mg of protein and of high affinity, with an apparent dissociation constant (KD) of 1.8 nM. The specificity of the binding site for various ligands was more similar to that of alpha 2 receptors than to that of alpha 1. No specific binding of [3H]WB-4101 was found in the membranes derived from NG 108 cells. This finding also indicated that the [3H]DHE binding site in the cell is the alpha 2 receptor. GTP lowered the affinity of agonists for the [3H]DHE binding site, although the nucleotide hardly affected the affinity of antagonists including [3H]DHE.

Topics: Adrenergic alpha-Antagonists; Animals; Brain; Cell Line; Dihydroergotoxine; Dioxanes; Glioma; Guanosine Triphosphate; Hybrid Cells; Kinetics; Neoplasms, Experimental; Neuroblastoma; Rats; Receptors, Adrenergic; Receptors, Adrenergic, alpha; Synaptic Membranes

C1300 mouse neuroblastoma cells gradually accumulate lipofuscin-like pigment when they are maintained in culture. Pigment was demonstrated by positive straining for acid phosphatase and with periodic acid-Schiff stain. Pigment was formation in cells was reduced by exposure of the cells to lower doses of dihydroergotoxine mesylate which also induced neurite formation and increased protein synthesis. Since lipofuscin appears to originate as a result of wear and tear within the cells, the drug probably exerts its beneficial effects by reducing the rate of intracellular wear and tear associated with aging.

Topics: Animals; Cell Line; Cell Survival; Dihydroergotoxine; Dose-Response Relationship, Drug; Hydrogen-Ion Concentration; Lipofuscin; Mice; Neoplasms, Experimental; Nerve Tissue Proteins; Neuroblastoma; Neurons

Exposure of mouse neuroblastoma cells in culture to low pH for 8 days caused a sixfold increase in cell lipofuscin pigment. Pigment content was measured as the percent of cells having clumps of acid phosphatase-staining material. Hydergine, between 0.1 and 3 microgram/ml, caused a concentration-related decrease in pigment content. Hydergine also stimulated neurite formation in cells in regular pH medium and was slightly toxic to cells in low pH medium. These results support the use of neuroblastoma cells as an in vitro model for age pigment studies.

Topics: Acid Phosphatase; Aging; Animals; Cells, Cultured; Culture Media; Dihydroergotoxine; Lipofuscin; Mice; Models, Biological; Neoplasms, Experimental; Neuroblastoma; Pigments, Biological