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Here we demonstrate high-pulse-energy multiphoton microscopy (MPM) for intravital imaging of neurons and oligodendrocytes in the murine brain. Pulses with an order of magnitude higher energy (~ 10 nJ) were employed from a ytterbium doped fiber laser source at a 1-MHz repetition rate, as compared to the standard 80-MHz Ti:Sapphire laser. Intravital imaging was performed on mice expressing common fluorescent proteins, including green (GFP) and yellow fluorescent proteins (YFP), and TagRFPt. One fifth of the average power could be used for superior depths of MPM imaging, as compared to the Ti:Sapphire laser: A depth of ~ 860 µm was obtained by imaging the Thy1-YFP brain in vivo with 6.5 mW, and cortical myelin as deep as 400 µm ex vivo by intrinsic third-harmonic generation using 50 mW. The substantially higher pulse energy enables novel regimes of photophysics to be exploited for microscopic imaging. The limitation from higher order phototoxicity is also discussed.

Chicks that have undergone long-term selection for low body weight responded to intracerebroventricular amylin injection with reduced food intake at a dose considerably lower and with a greater magnitude suppression than those selected for high body weight. Behaviors unrelated to ingestion were not affected. These data support the thesis of correlated amylin system responses to selection for low or high body weight, with possible implications to other species., (Copyright 2009 Elsevier B.V. All rights reserved.)

The melanocortin system together with other appetite-related systems plays a significant role in appetite regulation. The appetite-related effects of one such melanocortin, beta-melanocyte-stimulating hormone (MSH), are well documented in rodents; however, its effects in the avian class are not thoroughly understood. Thus, we designed a study to determine the effects of i.c.v. beta-MSH injection on food and water intake, plasma corticosterone concentration, ingestive and non-ingestive behaviours, and hypothalamic neuronal activation using Cobb-500 chicks. Chicks responded to beta-MSH-treatment with a reduction in food and water intake; however when water intake was measured independently of food intake, it was not affected. beta-MSH-treated chicks also had increased plasma corticosterone concentrations and increased c-Fos reactivity in the periventricular, paraventricular and infundibular nuclei, and the ventromedial hypothalamus; however, the lateral hypothalamus was not affected. The effect on food intake is primary because behaviours that may be competitive with food intake were not increased in beta-MSH-treated chicks. Based on these results, we conclude that beta-MSH causes anorexigenic effects that are likely primarily mediated via stimulation of satiety-related hypothalamic nuclei in broiler-type chicks.