Dietary effects of structured lipids and phytosteryl esters on cardiovascular function in spontaneously hypertensive rats.
This study examined the dietary effects of sesame oil (SO)-based structured lipids (SL) and phytosteryl esters (PE) on cardiovascular function in conscious spontaneously hypertensive rats (SHR) fed high-fat (HF) diets (20% w/w fat). The dietary groups were as follows: normal diet (4.5% w/w fat), SO, SO fortified with PE (SOP), SL, and SL fortified with PE (SLP). Mean arterial blood pressures were similar in all groups, whereas resting heart rates (HR) were higher in all HF-fed groups. The pressor responses to the alpha1-adrenoceptor agonist, phenylephrine (5 microg/kg), were similar in all groups. However, the pressor responses to phenylephrine (10 microg/kg) were diminished in SO- or SL-fed SHR, whereas they were not diminished in SOP- or SLP-fed SHR. The depressor responses elicited by the nitric oxide (NO) donor, sodium nitroprusside (5 and 10 microg/kg), were not diminished in HF-fed rats. Baroreflex-mediated changes in HR were variously decreased in the HF-fed groups, and this decrease tended to be greater in SOP and SLP than in SO and SL groups. The depressor and tachycardic responses elicited by the beta-adrenoceptor agonist, isoproterenol, were equivalent in all groups. The depressor responses elicited by the endothelium-dependent agonist, acetylcholine (0.1 microg/kg), and the hypertension elicited by the NO synthesis inhibitor, NG-nitro-L-arginine methylester (25 micromol/kg), were similar in all groups. These findings demonstrate that (1) HF diets increase resting HR and impair baroreflex function in SHR, whereas they do not obviously affect endothelium-dependent vasodilation, and (2) fortification with PE may be deleterious to cardiovascular function (eg, baroreflex activity) in SHR.
Kim
Byung Hee
BH
Department of Food Science and Technology, University of Georgia, Athens, Georgia 30602-7610, USA.
Sandock
Kevin D
KD
Robertson
Tom P
TP
Lewis
Stephen J
SJ
Akoh
Casimir C
CC
D000818:Animals; D017704:Baroreflex / Q000187:drug effects; D001794:Blood Pressure / Q000187:drug effects; D002319:Cardiovascular System / Q000187:drug effects* / Q000503:physiopathology; D004041:Dietary Fats / Q000009:adverse effects* / Q000494:pharmacology; D004730:Endothelium, Vascular / Q000187:drug effects; D006339:Heart Rate / Q000187:drug effects; D006973:Hypertension / Q000503:physiopathology*; D008297:Male; D010840:Phytosterols / Q000009:adverse effects* / Q000494:pharmacology; D011897:Random Allocation; D051381:Rats; D011918:Rats, Inbred SHR; D012715:Sesame Oil / Q000009:adverse effects / Q000494:pharmacology; D014664:Vasodilation / Q000187:drug effects
D004041:Dietary Fats; D010840:Phytosterols; D012715:Sesame Oil