Effects of a medium-chain triglyceride:fish oil emulsion administered intravenously to omega3 fatty acid-depleted rats on cationic fluxes in aortic rings.
The handling of 45Ca and 86Rb by aortic rings obtained from rats depleted in long-chain polyunsaturated omega3 fatty acids (second generation) was examined in vitro over 10 to 60 min incubation at either increasing concentrations of extracellular K+ (5, 3 and 60 mM) in the case of 45Ca net uptake or in the absence and presence of ouabain (50 microM) in the case of 86Rb uptake. The omega3-depleted rats were injected intravenously 120 min before sacrifice with 1.0 ml of either an omega3 fatty acid-rich medium-chain triglyceride:fish oil emulsion (MCT:FO) or a control medium-chain triglyceride:olive oil emulsion (MCT:OO). In the MCT:OO-injected rats, the rise in extracellular K+ concentration failed to stimulate 45Ca net uptake, whilst the prior injection of the MCT:FO emulsion restored the expected increase in 45Ca net uptake by aortic rings exposed to 60 mM K+. The absolute value for 86Rb net uptake after 10 or 60 min incubation and whether in the absence or presence of ouabain, which significantly decreased the uptake of 86Rb+ after 60 min incubation, only represented in the MCT:FO-injected rats 63.1+/-3.8% of the mean corresponding values found in MCT:OO-injected animals. These findings are consistent with the view that activity of cationic channels, such as the voltage-sensitive Ca2+ channel, the outflow of Ca2+ as mediated by either Na+-Ca2+ countertransport or a Ca2+-ATPase, the activity of Na+,K+-ATPase and the modality of K+ inflow by an oubain-resistant modality are all affected in aortic cells by the content of long-chain polyunsaturated omega3 fatty acids in membrane phospholipids.
Courtois
Philippe
P
Laboratory of Experimental Hormonology, Brussels Free University, Brussels, Belgium.
Louchami
Karim
K
Portois
Laurence
L
Chardigny
Jean-Michel
JM
Sener
Abdullah
A
Carpentier
Yvon S
YS
Malaisse
Willy J
WJ
D000818:Animals; D001011:Aorta / Q000187:drug effects / Q000378:metabolism*; D002412:Cations / Q000378:metabolism*; D005217:Fat Emulsions, Intravenous / Q000008:administration & dosage* / Q000737:chemistry / Q000494:pharmacology*; D015525:Fatty Acids, Omega-3 / Q000032:analysis / Q000378:metabolism*; D005260:Female; D066298:In Vitro Techniques; D051381:Rats; D014280:Triglycerides / Q000008:administration & dosage / Q000737:chemistry* / Q000494:pharmacology*
D002412:Cations; D005217:Fat Emulsions, Intravenous; D015525:Fatty Acids, Omega-3; D014280:Triglycerides