Lack of modulation by dietary unsaturated fats on sympathetic neurotransmission in rat hearts.
We examined the effect of dietary polyunsaturated fatty acids (PUFA) on cardiac sympathetic neurotransmission. Rats were fed semisynthetic diets (18.5% fat wt/wt) high in saturated fatty acids (control diet), high in n-6 PUFA (corn oil), or enriched with n-3 PUFA (Maxepa). A perfused innervated heart model was used to examine different aspects of sympathetic neurotransmission 10 wk after the feeding. Dietary PUFA increased the content of n-6 or n-3 PUFA in myocardial phospholipids compared with animals fed control diets. Myocardial norepinephrine content, sympathetic nerve stimulation-induced norepinephrine release, neural reuptake, presynaptic alpha-adrenergic inhibition of norepinephrine release, and postsynaptic inotropic response (+/- dP/dt) to sympathetic nerve stimulation or to a beta-agonist were essentially not influenced by dietary PUFA. Neural norepinephrine release during prolonged ischemia (60 min) was also similar in hearts from rats fed n-6 PUFA and control diets. Thus a modification of sympathetic neurotransmission was not achieved by feeding PUFA-enriched diets for 10 wk.
Du
X J
XJ
Department of Medicine (Royal Infirmary of Edinburgh), University of Edinburgh, United Kingdom.
Dart
A M
AM
Riemersma
R A
RA
D000818:Animals; D004041:Dietary Fats / Q000494:pharmacology*; D004558:Electric Stimulation; D005224:Fats, Unsaturated / Q000494:pharmacology*; D005227:Fatty Acids / Q000378:metabolism; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated / Q000494:pharmacology; D006329:Heart Conduction System / Q000187:drug effects*; D007545:Isoproterenol / Q000494:pharmacology; D008297:Male; D009200:Myocardial Contraction / Q000187:drug effects; D017202:Myocardial Ischemia / Q000378:metabolism; D009206:Myocardium / Q000378:metabolism; D009638:Norepinephrine / Q000378:metabolism; D051381:Rats; D011917:Rats, Inbred Lew; D013564:Sympathetic Nervous System / Q000187:drug effects* / Q000378:metabolism; D009435:Synaptic Transmission / Q000187:drug effects*
D004041:Dietary Fats; D005224:Fats, Unsaturated; D005227:Fatty Acids; D043371:Fatty Acids, Omega-6; D005231:Fatty Acids, Unsaturated; D007545:Isoproterenol; D009638:Norepinephrine