Accession Number : ADA299213

Title :   Comparison of Cytosolic Ca2+ and Exocytosis Responses from Single Rat and Bovine Chromaffin Cells.

Descriptive Note : Technical rept. Jul-Dec 95,

Corporate Author : NORTH CAROLINA UNIV AT CHAPEL HILL DEPT OF CHEMISTRY

Personal Author(s) : Finnegan, Jennifer M. ; Borges, Ricardo ; Wightman, R. M.

PDF Url : ADA299213

Report Date : 13 SEP 1995

Pagination or Media Count : 35

Abstract : The relationship between cytosolic Ca2+ and catecholamine secretion during stimulus secretion coupling has been examined at individual chromaffin cells isolated from the cow and rat. Vesicular catecholamine exocytosis was determined via amperometric measurements with carbon fiber microelectrodes and fura-2 was used for simultaneous fluorescent monitoring of cytosolic Ca2+ at the same cell. Individual secretory vesicles in cells from the two species were found to release similar amounts of catecholamine. In addition the time courses for secretion from individual vesicles was similar with rat and bovine chromaffin cells. The total quantity of catecholamine released and the change in cytosolic Ca2+ were also similar in response to exposure to K+ (60 mM), DMPP (50 pM), and histamine (50 pM), although both responses were more prolonged following DMPP and histamine at bovine cells. Agents that mobilize intracellular Ca2+-stores such as methacholine, caffeine and bradykinin resulted in different cytosolic Ca2 and exocytosis responses at the rat and bovine chromaffin cells. Results indicates a heightened Ca2 store activity or a more filled state in chromaffin cells from the rat. The results of this study clearly show that single cell techniques can be used to characterize stimulus-secretion coupling. The requirement for lower numbers of cells with these techniques means that chromaffin cells from rodents can be routinely employed. This can be advantageous to minimize biological variabilit%1 which occurs with organs obtained from slaughter houses and enables the investigation of genetically-altered animals.

Descriptors :   *CATECHOLAMINES, *BOVINES, *CHROMIUM COMPOUNDS, COUPLING(INTERACTION), FLUORESCENCE, RATS, MONITORING, CHEMICAL PROPERTIES, QUANTITY, CARBON FIBERS, ELECTRODES, SYNCHRONISM, RODENTS, CELLS(BIOLOGY), CAFFEINE, ORGANS(ANATOMY), SECRETION, HISTAMINE, PARASYMPATHOMIMETIC AGENTS.

Subject Categories : Biochemistry
      Biology
      Organic Chemistry

Distribution Statement : APPROVED FOR PUBLIC RELEASE