title: Effect of age on high-fat diet-induced hypertension.
abstract: Aging and obesity both have a significant impact on central blood pressure (BP) regulation, and previous studies indicated that changes in central redox signaling with age may affect high-fat (HF) diet-induced cardiovascular responses. Therefore, we investigated the effects of 60% HF feeding on BP regulation in young adult (5 mo) and old (26 mo) Fischer-344 × Brown-Norway rats. Radiotelemetric transmitters were implanted to measure BP, heart rate (HR), locomotor activity, and spontaneous baroreflex sensitivity. Expression and activity of NADPH oxidase and ANG II type 1 receptor were assessed in the hypothalamus and in the nucleus tractus solitarii. Old animals gained more weight on HF diet compared with young, whereas central NADPH oxidase expression and activity elevated similarly in the two age groups. After an initial hypotensive and tachycardic response during the first week of HF feeding, BP in young animals increased and became significantly elevated after 6 wk of HF feeding. In contrast, BP in old animals remained depressed. Nighttime HR and locomotor activity decreased in both young and old rats fed with HF diet, but these changes were more significant in young rats. As a result, amplitudes of circadian variation of BP, HR, and activity that were originally higher in young rats declined significantly and became similar in the two age groups. In conclusion, our experiments led to the surprising finding that HF diet has a more serious impact on cardiovascular regulation in young animals compared with old.
authors.affiliation: Dept. of Pharmacology & Therapeutics, Univ. of Florida, College of Medicine, P.O. Box 100267, Gainesville, FL 32610-0267, USA. erdos@ufl.edu
authors.forename: Benedek
authors.initials: B
authors.lastname: Erdos
authors.forename: Nataliya
authors.initials: N
authors.lastname: Kirichenko
authors.forename: Melissa
authors.initials: M
authors.lastname: Whidden
authors.forename: Bilgen
authors.initials: B
authors.lastname: Basgut
authors.forename: Mary
authors.initials: M
authors.lastname: Woods
authors.forename: Idan
authors.initials: I
authors.lastname: Cudykier
authors.forename: Rabih
authors.initials: R
authors.lastname: Tawil
authors.forename: Philip J
authors.initials: PJ
authors.lastname: Scarpace
authors.forename: Nihal
authors.initials: N
authors.lastname: Tumer
mesh_terms: D000375:Aging / Q000502:physiology*; D000818:Animals; D017704:Baroreflex / Q000502:physiology; D001794:Blood Pressure / Q000502:physiology; D015153:Blotting, Western; D001835:Body Weight / Q000502:physiology; D002784:Cholesterol / Q000097:blood; D004032:Diet; D004041:Dietary Fats; D006339:Heart Rate / Q000502:physiology; D006973:Hypertension / Q000209:etiology / Q000503:physiopathology*; D007031:Hypothalamus / Q000378:metabolism; D008297:Male; D009043:Motor Activity / Q000502:physiology; D019255:NADPH Oxidases / Q000378:metabolism; D009765:Obesity / Q000209:etiology / Q000503:physiopathology*; D051381:Rats; D011914:Rats, Inbred BN; D011916:Rats, Inbred F344; D044140:Receptor, Angiotensin, Type 1 / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction; D017552:Solitary Nucleus / Q000502:physiology; D013686:Telemetry
chemical_list: D004041:Dietary Fats; D044140:Receptor, Angiotensin, Type 1; D002784:Cholesterol; D019255:NADPH Oxidases