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Acta Physiologica 2012; Volume 206, Supplement 693
Joint FEPS and Spanish Physiological Society Scientific Congress 2012
9/8/2012-9/11/2012
Santiago de Compostela, Spain
CAROTID BODY RELATED FUNCTIONS IN RATS SUBJECTED TO INTERMITTENT HYPOXIA, FED WITH HIGH FAT DIET AND BOTH TREATMENTS APPLIED SIMULTANEOUSLY.
Abstract number: P81
Yubero1 S, Gallego-Martin1 T, Rocher1 A, Olea1 E, Gonzalez1 C, Obeso1 A
1Dept. Biochem. & Biol. Mol. & Phisiology, School of Medicine; Uni. Valladolid-IBGM & CIBERES
Objectives:
Obstructive sleep apnea creates an intermittent hypoxia (IH) every night during sleep time. Repetitive stimulation by IH sensitizes the carotid body (CB) causing permanent reflex sympathetic activation which generates hypertension and a tendency to increase acute vascular accidents. Thus, the CB is at the origin of the cardiovascular pathology in the obstructive sleep apnea syndrome (OSAS). In addition, obesity is a known factor to generate or aggravate OSAS pathologies.
Materials:
We have studied the existence of interactions between IH and obesity to alter CB function to define if CB altered by IH and/or obesity modifies sympathetic related parameters. We used male Wistar rats fed for 12 weeks (3-6 months of age) with regular or high fat diet (HFD; 10 and 60% fat). We defined four groups: control (C), CIH, obese (O) and OIH. Protocol of IH was: 5% O2, 40s/ 21% O2, 80s, 8h/day, 15 days (weeks 10-12 of HFD or equivalent age in regular diet animals).
Results:
A. Parameters CB related. Dopamine (DA) and norepinephrine (NE) levels increased in the CB in CIH, O and OIH rats. In CIH and O rats DA and NE synthesis rates augmented, with a further increase in OIH rats. DA release induced by hypoxia augmented in CIH and that induced by high K+ augmented in CIH, O and OIH groups. Hypoxia and high CO2 elicited increases in minute ventilation (MV) was normal in O but diminished in CIH and OIH groups. B. Sympathetic related parameters. Plasma NE and epinephrine (E) levels were augmented in CIH, O, and OIH. Similarly NE levels increased in the renal artery of CIH, O, and OIH rats, and more importantly, NE rate of synthesis (a measure of NE release or sympathetic tone) augmented in CIH and more than doubled in O and OIH groups. Finally, mean arterial pressure (88 mmHg in C) was progressively higher IH, O and OIH rats. Findings were always expressed vs. C group.
Conclusions:
Thus, IH and obesity interact to modify CB function and sympathetic tone.
Grants: BFU2007-61848, PT2009-0172, JCyL2011 (Sanidad) and CIBERES
To cite this abstract, please use the following information:
Acta Physiologica 2012; Volume 206, Supplement 693 :P81