Physiology & behavior
-
Physiology & behavior · May 2014
C-Fos activation in the periaqueductal gray following acute morphine-3β-D-glucuronide or morphine administration.
Morphine-3β-D-glucuronide (M3G), a primary morphine metabolite, evokes hyperalgesia in mice and rats and putatively mediates hyperalgesia associated with morphine (MOR) administration. However, M3G does not act via opioid receptors and its locus of activity in the CNS is unknown. Here we assessed the density of neurons immunoreactive for c-Fos, an immediate early gene regulated by neuronal activity, in the periaqueductal gray (PAG), a midbrain region critical to pain modulation, in male CD-1 mice after MOR and M3G exposure. ⋯ However, NTX pre-injection blocked this increase in MOR but not M3G injected mice. The data demonstrate for the first time a CNS locus for M3G activity. Consistent with previous observations, this M3G activity is not mediated by opioid receptors.
-
Physiology & behavior · May 2014
Effects of energy status and diet on Bdnf expression in the ventromedial hypothalamus of male and female rats.
Sex differences exist in the regulation of energy homeostasis in response to calorie scarcity or excess. Brain-derived neurotrophic factor (BDNF) is one of the anorexigenic neuropeptides regulating energy homeostasis. Expression of Bdnf mRNA in the ventromedial nucleus of the hypothalamus (VMH) is closely associated with energy and reproductive status. ⋯ Decreased BDNF signaling during HFD feeding would increase a drive to eat and may contribute to diet-induced obesity in males. In contrast, VMH Bdnf expression was stably maintained in females when energy homeostasis was disturbed. These results suggest sex-distinct regulation of central Bdnf expression by diet and energy status.
-
Physiology & behavior · Apr 2014
Panax quinquefolium involves nitric oxide pathway in olfactory bulbectomy rat model.
Olfactory bulbectomy (OBX) is a well known screening model for depression. Panax quinquefolium (PQ) is known for its therapeutic potential against several psychiatric disorders. Nitric oxide (NO), an intercellular messenger has been suggested to play a crucial role in the pathogenesis of depression. ⋯ Treatment with PQ significantly and dose-dependently restored these behavioral, biochemical and molecular alterations associated with OBX. Further, pretreatment of l-NAME with subeffective dose of PQ (100mg/kg) significantly potentiated its protective effects; however l-arginine pretreatment reversed the beneficial effects. The present study suggests that protective effect of P. quinquefolium might involve nitric oxide modulatory pathway against olfactory bulbectomy-induced depression in rats.
-
Physiology & behavior · Apr 2014
Randomized Controlled TrialPectin is not pectin: a randomized trial on the effect of different physicochemical properties of dietary fiber on appetite and energy intake.
An increased intake of dietary fiber has been associated with reduced appetite and reduced energy intake. Research on the effects of seemingly identical classes of dietary fiber on appetite has, however, resulted in conflicting findings. The present study investigated the effects of different fiber properties, including methods of supplementation, on appetite and energy intake. ⋯ Different methods of supplementation resulted in distinct metabolic parameters. Results suggest that different physicochemical properties of pectin, including methods of supplementation, impact appetite and energy intake differently. Reduced appetite was probably mediated by preload physical properties, whereas inconsistent associations with metabolic parameters were found.
-
The time of day at which meals are consumed is known to impact on behaviour as well as physiological systems. In this study we investigated the behavioural and physiological effects of restricting access to food to the light or dark period in mice maintained on either long or short photoperiods. In both photoperiods, wheel running commenced upon the onset of darkness and was generally confined to the period of darkness. ⋯ The rhythm of expression of liver Bmal1 mRNA was similar in light and dark fed mice after 7 and 35 days on the schedule while the Per1, Per2, Nr1d1 and Dbp mRNA rhythms were delayed on average by 3.5±1.1 h and 3.7±0.9 h in light fed mice after 7 and 35 days respectively compared to dark fed mice. Rhythms of metabolically important genes were shifted in light fed mice compared to dark fed, by 5 h or became arrhythmic. This study shows that not only circadian rhythms facilitate metabolic control, but also different environmental events, including season and feeding opportunities, alter aspects of circadian and metabolic physiology.