Increased NPY activity in the PVN contributes to food-restriction induced reductions in blood pressure in aortic coarctation hypertensive rats

Jm, VanNess; Je, DeMaria; Jm, Overton

doi:10.1016/s0006-8993(99)01058-6

Cited by 20 publications

(13 citation statements)

References 40 publications

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“…Additional general support for the involvement of NPY in foraging springs forth from two independent, accidental observations in cardiovascular pharmacology, where it was noted that laboratory rats behave as though they are foraging for food during tests of the effects of centrally administered NPY on cardiovascular function (19,41). In addition, a role for NPY in appetitive ingestive behavior also is suggested, because centrally administered NPY does not stimulate sucrose intake when rats are passively fed a sucrose solution through an intraoral catheter (36).…”

Section: Discussionmentioning

confidence: 99%

“…The ability of centrally applied NPY to stimulate food intake by laboratory rats (10,26,37), mice (31), and Siberian hamsters (6), as well as the suggestion that it increases appetitive ingestive behavior in rats [e.g., foraging (19,41)], makes it a potential candidate for investigation. In addition, NPY arcuate nucleus gene expression increases with food deprivation in laboratory rats (8,42) as well as in Siberian hamsters (29) (for review, see Ref.…”

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confidence: 99%

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Role of NPY and its receptor subtypes in foraging, food hoarding, and food intake by Siberian hamsters

Day

Keen-Rhinehart

Bartness

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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Fasting has widespread physiological and behavioral effects such as increases in arcuate nucleus neuropeptide Y (NPY) gene expression in rodents, including Siberian hamsters. Fasting also stimulates foraging and food hoarding (appetitive ingestive behaviors) by Siberian hamsters but does relatively little to change food intake (consummatory ingestive behavior). Therefore, we tested the effects of third ventricular NPY Y1 ([Pro 34 ]NPY) or Y5 ]NPY) receptor agonists on these ingestive behaviors using a wheel running-based food delivery system coupled with simulated burrow housing. Siberian hamsters had 1) no running wheel access and free food, 2) running wheel access and free food, or 3) foraging requirements (10 or 50 revolutions/pellet). NPY (1.76 nmol) stimulated food intake only during the first 4 h postinjection (ϳ200 -1,000%) and mostly in hamsters with a foraging requirement. The Y1 receptor agonist markedly increased food hoarding (250 -1,000%), increased foraging as well as wheel running per se, and had relatively little effect on food intake (Ͻ250%). Unlike NPY, the Y5 agonist significantly increased food intake, especially in foraging animals (ϳ225-800%), marginally increased food hoarding (250 -500%), and stimulated foraging and wheel running 4 -24 h postinjection, with the distribution of earned pellets favoring eating versus hoarding across time. Across treatments, food hoarding predominated early postinjection, whereas food intake tended to do so later. Collectively, NPY stimulated both appetitive and consummatory ingestive behaviors in Siberian hamsters involving Y1/Y5 receptors, with food hoarding and foraging/wheel running (appetitive) more involved with Y1 receptors and food intake (consummatory) with Y5 receptors.appetitive; consummatory; wheel running; neuropeptide Y; Y1 and Y5 receptors ANIMAL BEHAVIORIST Wallace Craig in 1918 coined the terms "appetitive" and "consummatory" for the two-part sequence of eating, drinking, and sexual behaviors (13), referring to the seeking and completion of the goal object, respectively. In terms of appetitive ingestive behavior, this consists of food acquisition (foraging) and subsequent storage for future use (hoarding; for review, see Ref. 40), whereas consummatory ingestive behavior is feeding. Considerable effort has been made toward understanding the physiological mechanisms underlying consummatory ingestive behaviors, whereas much less is known about the physiological mechanisms underlying appetitive ingestive behaviors. We have been studying the appetitive ingestive behaviors of food hoarding (2, 3, 44) and, more recently, foraging (15-17) in Siberian hamsters (Phodopus sungorus). In most species, shortfalls in food availability trigger increases in foraging and increases in food intake once food is found, whereas in hamster species, including Siberian hamsters, fasting stimulates foraging and food hoarding with minimal increases in food intake (for review, see Ref. 16). To begin to discover the mechanisms underlying appetitive ingestive behaviors,...

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Section: Discussionmentioning

confidence: 99%

mentioning

confidence: 99%

Role of NPY and its receptor subtypes in foraging, food hoarding, and food intake by Siberian hamsters

Day

Keen-Rhinehart

Bartness

2005

American Journal of Physiology-Regulatory, Integrative and Comp

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“…These findings suggest that some but not all of the leptin-induced sympathetic activation are mediated via hypothalamic melanocortin system. Because central administration of neuropeptide Y (NPY) reduces BP in rats and dogs (47,48), decreased hypothalamic NPY production by exogenous administration of leptin (49) and in transgenic skinny mice (Y. Ogawa et al, unpublished data) might be involved in hypertensive effect of leptin.…”

Section: Discussionmentioning

confidence: 99%

Pathophysiological role of leptin in obesity-related hypertension

Aizawa-Abe¹,

Ogawa²,

Masuzaki³

et al. 2000

J. Clin. Invest.

434

312

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IntroductionObesity is defined as increased mass of adipose tissue and confers a higher risk of arterial blood pressure (BP) elevation or hypertension (1-4). On the other hand, weight reduction lowers BP in obese hypertensive subjects (5-8), suggesting an important association between energy homeostasis and BP. However, the mechanism for that association is poorly understood. Obesity-related hypertension may be secondary to insulin resistance and/or hyperinsulinemia (2,3,8). Several lines of evidence have also suggested that increased sympathetic nerve activity may contribute to the development of obesity-related hypertension (2, 6, 7).The adipose tissue participates in the regulation of a variety of homeostatic processes as an endocrine organ that secretes many biologically active molecules such as FFA, adipsin, angiotensinogen,. Leptin is such an adipocyte-derived hormone that is involved in the regulation of food intake and body weight (10). It also increases the overall sympathetic nerve activity, which leads to a significant increase in energy expenditure (11-15). The biologic actions of leptin are thought to be mediated through the activation of leptin receptor that is expressed in the hypothalamus (16)(17)(18)(19). We and others demonstrated that the hypothalamic arcuate nucleus is a primary site of the satiety effect of leptin (20,21) and that its satiety effect is mediated at least partly by hypothalamic melanocortin system (22,23).Numerous studies have demonstrated that plasma leptin concentrations are elevated significantly in several models of rodent obesity and in human obesity in proportion to the degree of adiposity (24-26), suggesting the state of "leptin resistance" in obesity. Nevertheless, because of the potent pleiotropic actions of leptin, it is conceivable, though paradoxically, that hyperleptinemia may be involved in the pathogenesis of obesity and its related disorders. In this regard, a recent study reported a significant correlation between BP and plasma leptin concentrations in patients with essential hypertension (27), suggesting that leptin may play roles in the pathogenesis of obesity-related hypertension.We have recently produced transgenic skinny mice overexpressing leptin under the control of the liver-specific promoter and demonstrated that chronic hyperleptinemia results in complete disappearance of adipose tissue for a long period (28). These mice also exhibit increased glucose metabolism and insulin sensitivity, accompanied by an activation of insulin signaling in the skeletal muscle and liver (28,29). Accordingly, transgenic skinny mice will serve as the unique experimental model system with which to assess the long-term effects of leptin in vivo. To explore the pathophysiological role of leptin in obesity-related hypertension, we examined cardiovascular phenotypes of transgenic skinny mice whose elevated plasma leptin concentrations are comparable to those seen in obese subjects. We also studied genetically obese KKA y mice with hyperleptinemia, in which hypothalamic melano...

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“…There is thus considerable evidence suggesting that reduced sympathetic activity may serve as an important mechanism behind the reduction in blood pressure following decreased caloric intake [64] .…”

Section: Effect Of Cr On Cardiovascular Disease and Cardio Patho Logymentioning

confidence: 99%

Caloric restriction and heart function: is there a sensible link?

Han

Ren

2010

Acta Pharmacol Sin

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Calorie restriction (CR) is defined as a reduction in calorie intake below the usual ad libitum intake without malnutrition. In general, the daily caloric intake subjected to CR has been restricted to 50% to 70% of the average food intake in subjects eating ad libitum [1,2] . CR was first reported to retard aging and prolong median and maximal life span in the 1930s [3] . Over the last several decades, CR has been widely studied which exhibits an apparent beneficial impact on longevity, ageassociated diseases, and attenuation of functional decline, across a broad variety of species (including rats, mice, fish, flies, worms and yeast) [4,5] . Moreover, CR provides protection against a cadre of chronic diseases including diabetes mellitus, neurodegenerative diseases, autoimmune disorders [6][7][8] and cancer [9][10][11][12] . CR has been shown to alter a variety of physiological parameters especially reduced metabolic rate and oxidative damage, resulting in a decrease in the incidence of cardiovascular diseases [13] . In response to energy deficiency, experimental animals experience a drastic decrease in both fat mass and lean body mass. Muscle mass is overtly reduced, although the rate of loss of function and mass/body weight with the aging process is attenuated [9,[14][15][16] . Metabolic rate may decrease transiently although studies have indicated similar metabolic rate per kg lean body mass to that of ad libitum fed rodents in longterm CR protocol [17] . Body temperature, systolic and diastolic blood pressure all decrease [18,19] along with the reduced sympathetic activity [20] . CR-treated animals are more spontaneously active and display superior cognitive abilities compared to their ad libitum counterparts [21,22] .The most prominent mechanism that may be responsible for the beneficial health and physiological effects of CR are usually mediated through increased insulin sensitivity which results in reduced plasma glucose and insulin concentrations and improved glucose tolerance [23] ; reduced levels of oxidative stress (decreased oxidative damage to proteins, lipids and DNA) [24] , increased resistance to various types of stress including heat, oxidative and metabolic stress [25] as well as enhanced immune function [26] . Impact of CR on agingAn inverse relationship between calorie intake and lifespan has been revealed in mice, suggesting a key role for regulators of energy metabolism in the mechanism of CR. Accordingly, CR-induced metabolic reprogramming may be a key event in the mechanism of lifespan extension [27,28] . The age when CR is started, the severity of restriction, and strain or genetic background of animals determine the magnitude of life extension. The only mammals in which CR has clearly been shown ReviewCaloric restriction and heart function: is there a sensible link? Calorie restriction (CR) is defined as a reduction in calorie intake below the usual ad libitum intake without malnutrition. Ample of clinical and experimental evidence has demonstrated that CR is capable of retarding aging p...

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Increased NPY activity in the PVN contributes to food-restriction induced reductions in blood pressure in aortic coarctation hypertensive rats

Cited by 20 publications

References 40 publications

Role of NPY and its receptor subtypes in foraging, food hoarding, and food intake by Siberian hamsters

Role of NPY and its receptor subtypes in foraging, food hoarding, and food intake by Siberian hamsters

Pathophysiological role of leptin in obesity-related hypertension

Caloric restriction and heart function: is there a sensible link?

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