Effect of acute and chronic caloric restriction and metabolic glucoprivation on spontaneous physical activity in obesity-prone and obesity-resistant rats

Abstract

Teske JA, Kotz CM. Effect of acute and chronic caloric restriction and metabolic glucoprivation on spontaneous physical activity in obesity-prone and obesity-resistant rats. Am J Physiol Regul Integr Comp Physiol 297: R176 -R184, 2009. First published May 6, 2009 doi:10.1152/ajpregu.90866.2008 and metabolic glucoprivation affect spontaneous physical activity (SPA), but it's unknown whether these treatments similarly affect SPA in selectively bred obesity-prone (OP) and -resistant (OR) rats. OR rats have greater basal SPA and are more responsive to treatments that modulate SPA, such as orexin A administration. We hypothesized that OR rats would be more sensitive to other treatments modulating SPA. To test this, continuous 24-h SPA was measured before and during acute (24 h) and chronic (8 wk) CR in OR, OP, and Sprague-Dawley rats. Pharmacological glucoprivation was produced by injection of 2-deoxyglucose (2-DG), and SPA was measured 5 h postinjection. Acute CR increased SPA in all groups; however, the effect was dependent on the index of SPA and time interval during the 24-h time period. In contrast to OR rats, chronic CR increased distance traveled, ambulatory episodes, and time spent in ambulation and stereotypy during the time interval preceding anticipation of food in OP and SpragueDawley rats. Although the effects of 2-DG treatment on SPA were minimal, OR rats had significantly greater SPA than OP and SpragueDawley rats independent of treatment. That chronic CR failed to result in significant changes in SPA in OR rats suggests that these rats may be especially unresponsive to treatments modulating feeding. This insensitivity coupled with elevated basal SPA levels may in part mediate phenotypic traits of lean rats. food deprivation; locomotor activity; diet-induced obesity THE RISING PREVALENCE OF OBESITY indicates that a sustained positive imbalance between energy intake and expenditure exists at the population level. However, it's unclear which factor, excessive intake or reduced energy expenditure, has contributed more to the obesity epidemic (19). Given the strong influence of genetics and environment on body weight gain, it's intriguing that spontaneous physical activity (SPA) has a strong familial and genetic component (65) and that lean adults and children display greater SPA than their obese counterparts (25,38). Similar to lean humans and nonhuman primates (63), rats selected for low weight gain [obesityresistant rats, (OR)] have greater SPA (57), body-weight adjusted SPA-associated energy expenditure (22), and nonresting energy expenditure (40). The response to treatments affecting food intake also differ between obese and lean rodents: weight gain following consumption of highly palatable diets (30) and weight regain after 50% caloric restriction (CR) is lower in OR rats (35). Further, fat oxidation was elevated in chow-fed OR rats (20). Moreover, total fat pad weight adjusted for body weight was significantly less in OR rats in response to early postweaning exercise (47). Hence, it's plausible t...

Gait-specific adaptation of locomotor activity in response to dietary restriction inCaenorhabditis elegans

“…Depending on the animal species examined, both decreases and increases in locomotor activity have been described in response to limited food supplies (Pirke et al, 1993;Weed et al, 1997;Geng et al, 2007;Teske and Kotz, 2009;Boehm et al, 2010;Gingerich et al, 2010;Yu et al, 2010). However, gait-specific effects have not been considered.…”

“…In contrast, rats show hyperactive wheel running in response to starvation (Koubi et al, 1991;Pirke et al, 1993). Similarly, caloric restriction increases physical activity in rats (Geng et al, 2007;Teske and Kotz, 2009) and rhesus monkeys (Weed et al, 1997). It is of note that up to 80% of human patients with the eating disorder anorexia nervosa show excessive physical activity (Koubi et al, 1991;Hebebrand et al, 2003).…”

Role of the locus coeruleus in enhanced orexin A-induced spontaneous physical activity in obesity-resistant rats

“…To avoid potential effects of recent food intake on gene expression, food was removed from the cages between 0700 and 0800. At this time, food intake is at a minimum in rodents and is similar between OR and Sprague-Dawley rats (48). Animals were euthansized between 1100 and 1200.…”

“…We used a selectively bred rodent model of obesity resistance, the OR rats, whereby phenotypic traits are expressed on a low-fat diet (39). We compared OR rats to Sprague-Dawley rats instead of the selectively bred obesity-prone rats, as we have found that Sprague-Dawley and obesity-prone rats are similar behaviorally and phenotypically and respond to orexin similarly (48,49). We hypothesized that 1) analysis of orexin receptors from multiple brain sites would differentiate OR and Sprague-Dawley rats and identify orexin receptors in the LC as significant to the OR phenotype; 2) compared with Sprague-Dawley rats, OR rats would have greater SPA, energy expenditure, SPA following orexin A infusion into the LC, and lower adiposity; and 3) orexin A-induced hyperphagia would be similar between groups.…”

Translational Science: How experimental research has contributed to the understanding of spontaneous Physical Activity and Energy Homeostasis

“…In Wistar rats, whereas moderate (30%) feed restriction did not change SPA, severe (approximately 80%) restriction reduced spontaneous activity, resulting in energetic economy 32 . In another study, chronic caloric restriction (CR) increased SPA during the time interval preceding anticipation of food in obesity-prone and Sprague-Dawley rats, but not in obesity-resistant rats, which already have elevated basal SPA 33 . Brzek et al 25 investigated the effect of a moderate CR on SPA in mice divergently selected for high or low basal metabolic rate.…”