Summer resting metabolic rates (RMR) differed significantly between altitudinal subpopulations of Amethyst Sunbirds. Summer basal metabolic rate was observed to decrease as altitude
decreased. Differences between pre-acclimation RMR (representing natural acclimatization to summer conditions in the field) and post-acclimation RMR (to 25 degrees C at 660 m asl for 6 weeks) were large. In particular, Sunbirds from the Underberg subpopulation increased RMR by 80.9% at 5 degrees C and 85.2% at 25 degrees C post-acclimation. This summer research complemented an earlier study on altitudinal variation in Amethyst Sunbirds in winter. It again emphasized the need to acknowledge altitudinal differences between subpopulations and not just use species means, as species means do not fully incorporate the effect of phenotypic selleck products plasticity/flexibility. (C) 2009 Elsevier Ltd. All rights Selleckchem Pitavastatin reserved.”
“We review our recent experimental and modeling results on how cerebellar Purkinje cells encode information in their simple spike trains and present a theory of the function of pauses and regular spiking patterns. The regular spiking patterns were discovered in extracellular recordings of simple spikes in awake and anesthetized
rodents, where it was shown that more than half of the spontaneous activity consists of short epochs of regular spiking. These periods of regular spiking are interrupted by pauses, which can be tightly synchronized among nearby Purkinje cells, while the spikes in the regular patterns are not. Interestingly, pauses are affected by long-term depression of the parallel fiber synapses.
Both in modeling and slice experiments it was demonstrated that long-term depression causes a decrease in the duration of pauses, leading to an increase of the spike output of the neuron. Based on these results we propose that pauses in the simple spike train form a temporal code which can lead to a rebound burst in the target deep cerebellar nucleus neurons. Conversely, the regular spike Celastrol patterns may be a rate code, which presets the amplitude of future rebound bursts. (C) 2009 IBRO. Published by Elsevier Ltd. All rights reserved.”
“We examined the effect of acclimation to moderate hyperthermic environment on the ACTH, TSH, T(3), T(4) and corticosterone level, as well as the relative weight of hypophysis, thyroid and adrenal glands in streptozotocin-diabetic rats. Increased activity of the hypothalamo-pituitary-adrenocortical (HPA) axis has been demonstrated in diabetic animals, whereas insulin treatment restores the changes. Heat acclimation reduces the level of ACTH and corticosterone in control animals and moderates the hormonal disturbances caused by diabetes. Simultaneously, our study revealed impairment in the activity of the liypothalamo-pituitary-thyroid (HPT) axis.