title: Contrasting effects of intermittent and continuous hypoxia on low O(2) evoked catecholamine secretion from neonatal rat chromaffin cells.
abstract: In the present study we examined the effects of intermittent (IH) and sustained hypoxia (SH) on low PO(2)-evoked catecholamine (CA) secretion from neonatal rat chromaffin cells. Experiments were performed on chromaffin cells isolated from rat pups exposed to either IH (P0-P5; 15 s hypoxia-5 min normoxia;8 h/day) or SH (hypobaric hypoxia; 0.4ATM). CA secretion from chromaffin cells was monitored by amperometry. Control chromaffin cells, from P5 rat pups, exhibited robust CA secretion in response to acute hypoxia. IH facilitated whereas SH attenuated hypoxia-evoked CA secretion. IH increased the epinephrine and norepinephrine content of the adrenal medulla whereas SH had no effect. These results demonstrate that neonatal exposures IH and SH exert diametrically opposed effects on acute hypoxia-evoked CA secretion from chromaffin cells and CA contents.
authors.affiliation: The Center for Systems Biology, Departments of Medicine, The University of Chicago, Chicago, IL 60637, USA. dangjai@uchicago.edu
authors.forename: Dangjai
authors.initials: D
authors.lastname: Souvannakitti
authors.forename: Ganesh K
authors.initials: GK
authors.lastname: Kumar
authors.forename: Aaron
authors.initials: A
authors.lastname: Fox
authors.forename: Nanduri R
authors.initials: NR
authors.lastname: Prabhakar
mesh_terms: D000313:Adrenal Medulla / Q000378:metabolism; D000818:Animals; D000831:Animals, Newborn; D002395:Catecholamines / Q000378:metabolism*; D019439:Chromaffin Cells / Q000378:metabolism*; D000860:Hypoxia / Q000378:metabolism*; D010100:Oxygen / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
chemical_list: D002395:Catecholamines; D010100:Oxygen