Circadian rhythm of renal blood flow in caged
sheep. Influence of eating and rumination

Denis, Nancy; Tebot, I.; Bonnet, Jeanne‐Marie; Cirio, A.

doi:10.22358/jafs/73925/2004

Cited by 2 publications

(3 citation statements)

References 7 publications

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“…The stimulatory effect of the meal on renal perfusion was also concluded from the decreasing RBF values during fasting, and from the high constant RBF values during the more continuous diurnal feeding in the ad libitum pattern. The profile of RBF changes after the morning meal was similar to that described in a previous work (Denis et al, 2004). A similar circadian rhythm, dependent on feeding time, was reported in another herbivore species, the rabbit, by using chronic implants of ultrasonic flow probes around the renal arteries (Barrett et al, 2001).…”

Section: Discussionsupporting

confidence: 86%

“…Little research has been done on the determination of RBF rhythm in ruminants, in spite of their particular feeding behavior (continuous feeding, rumination), end products of digestion, and metabolic pathways. In a previous report, we observed a significant 3-h increase in RBF after the morning meal in caged sheep fed once daily (Denis et al, 2004), indicating a possible influence of feeding on RBF. To confirm the association between feeding and RBF rhythm, it is necessary to monitor the RBF during imposed variations in feeding patterns (daytime, frequency, fasting).…”

Section: Introductionmentioning

confidence: 56%

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Roles of eating, rumination, and arterial pressure in determination of the circadian rhythm of renal blood flow in sheep1

Tebot¹,

Bonnet²,

Junot³

et al. 2009

Journal of Animal Science

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To assess the roles of feeding behavior (eating and rumination) and systemic arterial pressure (SAP) on determination of the circadian rhythm of renal blood flow (RBF), 20 sheep fitted with ultrasonic flow-metering probes around both renal arteries and a submandibular balloon to monitor jaw movements (6 of them with a telemetry measurement system into the carotid artery for SAP recording), were successively assigned to 6 feeding patterns: once daily in the morning (0900 to 1100 h), afternoon (1700 to 1900 h), or evening (1900 to 2100 h); twice daily at 0900 to 1100 h and 1700 to 1900 h; ad libitum (food renewed each 2 h); and fasting (40 h). All protocols were carried out in autumn-winter, and the fasting pattern was repeated in spring-summer to evaluate the effect of the daylight length on RBF. In the once-daily feeding patterns, a rapid increase in RBF (P < 0.05 vs. 1-h prefeeding mean values) subsequent to the onset of meals was observed, followed by a progressive increase (P < 0.05), reaching a maximum 4 to 6 h after the beginning of eating, and a subsequent gradual decline until the next meal [differences vs. prefeeding values were no longer significant after 11 h (morning pattern), 13 h (afternoon pattern), and 15 h (evening pattern) from the beginning of eating]. In the twice-daily feeding pattern, each meal was also followed by an increase in RBF (P < 0.05 vs. prefeeding values), reaching a maximum 3 to 5 h after the onset of meals, and a posterior decline [differences vs. prefeeding values were no longer significant after 8 h (morning meal) and 5 h (afternoon meal) from the beginning of eating]. In the ad libitum feeding, no apparent rhythm in RBF was found. During fasting, a progressive reduction of RBF was observed from 2 h after the beginning of fasting (P < 0.05 vs. the mean value of the first fasting hour), with a slight rebound (P < 0.05) lasting several hours from approximately 0700 h in autumn-winter and approximately 0500 h in spring-summer. No change in the RBF profile was observed in association with rumination. Except during meals, no correlation was found between RBF and SAP. A detailed description of RBF and SAP recordings is presented. In conclusion, results showed a circadian rhythm of RBF determined by eating behavior, but not by rumination, that was independent of blood pressure and that seemed superimposed on a primary lighting-cycle-dependent RBF rhythm.

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Section: Discussionsupporting

confidence: 86%

Section: Introductionmentioning

confidence: 56%

Roles of eating, rumination, and arterial pressure in determination of the circadian rhythm of renal blood flow in sheep1

Tebot¹,

Bonnet²,

Junot³

et al. 2009

Journal of Animal Science

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“…An insulin-induced vasodilatatory response has been reported in different species (Muniyappa et al, 2007), and plasma insulin increases after meals in ruminants (Trenkle, 1978;Mineo et al, 1990). In a sheep model, we observed an increase in RBF after meals, independent of blood pressure (Denis et al, 2004;Tebot et al, 2009). Consequently, a causal relationship between insuhn and the meal-associated RBF changes could be proposed.…”

Section: Introductionsupporting

confidence: 70%

The effect of intravenous insulin infusion on renal blood flow in conscious sheep is partially mediated by nitric oxide but not by prostaglandins1

Tebot

Bonnet²,

Paquet³

et al. 2012

Journal of Animal Science

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To test the effect of insulin on renal perfusion and the participation of NO and PG as mediators of this response, renal blood flow (RBF) was measured in sheep (n = 8) implanted with ultrasonic flow probes around renal arteries and with a systemic arterial pressure (SAP, n = 4) telemetry device. Three protocols were performed: 1) RBF and SAP were recorded (0800 to 1800 h) in fed and fasted sheep, with the latter receiving intravenous (i.v.) infusions (0.5 mL/min) of insulin at 2 or 6 mU/(kg·min); 2) fasted sheep received i.v. infusions of either an inhibitor of NO synthesis (N(G)-nitro-L-arginine methyl ester, L-NAME) alone [0.22 mg/(kg·min), 1000 to 1200 h] or L-NAME (1000 to 1200 h) + insulin during the second hour (6 mU/(kg·min), 1100 to 1200 h); and 3) the same protocol was followed as in protocol 2, substituting L-NAME with ketoprofen [0.2 mg/(kg·min)], a cyclooxygenase inhibitor. In all protocols, plasma insulin and glucose were determined. During insulin administration, euglycemia was maintained and hypokalemia was prevented by infusing glucose and KCl solutions. After the onset of meals, a long-lasting 18% increase in RBF and a 48% insulin increase were observed (P < 0.05), without changes in SAP. Low- and high-dose insulin infusions increased RBF by 19 and 40%, respectively (P < 0.05). As after meals, the increases in RBF lasted longer than the insulin increase (P < 0.05). The L-NAME infusion decreased RBF by 15% (P < 0.05); when insulin was added, RBF increased to preinfusion values. Ketoprofen decreased RBF by 9% (P < 0.05); when insulin was added, RBF increased to 13% above preinfusion values (P < 0.05). In no case was a modification in SAP or glucose noted during the RBF changes. In conclusion, insulin infusion mimics the meal-dependent increase in RBF, independent of SAP, and lasts longer than the blood insulin plateau. The RBF increase induced by insulin was only partially prevented by L-NAME. Ketoprofen failed to prevent the insulin-dependent RBF increase. Both facts suggested that complementary vasodilatatory agents accounted for the insulin effect on sheep renal hemodynamics.

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Circadian rhythm of renal blood flow in caged sheep. Influence of eating and rumination

Cited by 2 publications

References 7 publications

Roles of eating, rumination, and arterial pressure in determination of the circadian rhythm of renal blood flow in sheep1

Roles of eating, rumination, and arterial pressure in determination of the circadian rhythm of renal blood flow in sheep1

The effect of intravenous insulin infusion on renal blood flow in conscious sheep is partially mediated by nitric oxide but not by prostaglandins1

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