Inorganic thiophosphate effects on chromaffin cell structure and function

Nitric oxide and peroxynitrite induce cellular death in bovine chromaffin cells: Evidence for a mixed necrotic and apoptotic mechanism with caspases activation

Treatment of chromaffin cells with nitric oxide (NO) donors (SNP and SNAP) and peroxynitrite produces a time- and dose-dependent necrotic and apoptotic cell death. Necrotic cell death was characterized by both an increase in lactate dehydrogenase and ATP release and changes in nuclei and cell morphology (as seen with fluorescence microscopy analysis with propidium iodide and Hoechst 33342). Apoptotic cell death was characterized by nuclear fragmentation and presence of apoptotic cell bodies, by a decrease in DNA content, and by an increase in DNA fragmentation. Treatment of chromaffin cells with lipopolysaccharide (LPS) or cytokines (interferon-gamma, tumor necrosis factor-alpha) resulted only in apoptotic cell death. Apoptotic effects of NO-inducing compounds were specifically reversed, depending on the stimuli, by the NO scavenger carboxy-PTIO (CPTio) or by the NOS inhibitors L-NMA and thiocitrulline. NO-induced apoptotic death in chromaffin cells was concomitant to a cell cycle arrest in G0G1 phase and a decrease in the number of chromaffin cells in the G2M and S phases of cell cycle. All NO-producing compounds were able to induce activation of caspase 3 and cytochrome c release, and specific inhibitors of caspase 3 and 9, such as Ac-DEVD-CHO (CPP32) and Ac-Z-LEHD-FMK, respectively, prevented NO-induced apoptosis in chromaffin cells. These results suggest that chromaffin cells could be good models for investigating the molecular basis of degeneration in diseases showing death of catecholaminergic neurons, phenomenon in which NO plays an important role.

Amylase secretion by cultured porcine parotid cells

The similarity of porcine and human physiology and the availability of slaughterhouse tissues suggests the use of porcine parotid cells as a model for amylase secretion. A procedure is described for the isolation of porcine parotid cells by collagenase-P/dispase digestion of the tissue. The preparation consisted of individual cells and small aggregates that were maintained in primary culture, during which the cells formed aggregates that firmly attached to the plastic substrate. The amylase content of the cultured cells remained adequate for assay of secretory activity during culture for one week after isolation. Depending upon variations in experimental treatments, the cultured cells secreted approx. 35-65% of cellular amylase in response to a carbachol challenge. The cells were slightly responsive to long exposures to isoproterenol, and were unresponsive to nicotine, elevated extracellular K+ or substance P. Secretion induced by carbachol required extracellular Ca2+, was inhibited by atropine and occurred with a nearly linear response over a 30-min period. The Ca2+ ionophore A23187 was also a potent secretagogue for amylase secretion, producing levels of secretion equal to that induced by carbachol. The ease of preparation and the retention of amylase during primary culture suggests that the preparation will be useful in studies on muscarinic receptor-mediated control of amylase secretion.