title: Intragastric preloads of L-tryptophan reduce ingestive behavior via oxytocinergic neural mechanisms in male mice

authors: Gartner, Sarah Nicole

subjects: Science & Technology

abstract: Human and laboratory animal studies suggest that dietary supplementation of a free essential amino acid, l-tryptophan (TRP), reduces food intake. It is unclear whether an acute gastric preload of TRP decreases consumption and whether central mechanisms underlie TRP-driven hypophagia. We examined the effect of TRP administered via intragastric gavage on energy- and palatability-induced feeding in mice. We sought to identify central mechanisms through which TRP suppresses appetite. Effects of TRP on consumption of energy-dense and energy-dilute tastants were established in mice stimulated to eat by energy deprivation or palatability. A conditioned taste aversion (CTA) paradigm was used to assess whether hypophagia is unrelated to sickness. c-Fos immunohistochemistry was employed to detect TRP-induced activation of feeding-related brain sites and of oxytocin (OT) neurons, a crucial component of satiety circuits. Also, expression of OT mRNA was assessed with real-time PCR. The functional importance of OT in mediating TRP-driven hypophagia was substantiated by showing the ability of OT receptor blockade to abolish TRP-induced decrease in feeding. TRP reduced intake of energy-dense standard chow in deprived animals and energy-dense palatable chow in sated mice. Anorexigenic doses of TRP did not cause a CTA. TRP failed to affect intake of palatable yet calorie-dilute or noncaloric solutions (10% sucrose, 4.1% Intralipid or 0.1% saccharin) even for TRP doses that decreased water intake in thirsty mice. Fos analysis revealed that TRP increases activation of several key feeding-related brain areas, especially in the brain stem and hypothalamus. TRP activated hypothalamic OT neurons and increased OT mRNA levels, whereas pretreatment with an OT antagonist abolished TRP-driven hypophagia. We conclude that intragastric TRP decreases food and water intake, and TRP-induced hypophagia is partially mediated via central circuits that encompass OT.

text: Intragastric preloads of L-tryptophan reduce ingestive behavior via oxytocinergic neural mechanisms in male mice Human and laboratory animal studies suggest that dietary supplementation of a free essential amino acid, l-tryptophan (TRP), reduces food intake. It is unclear whether an acute gastric preload of TRP decreases consumption and whether central mechanisms underlie TRP-driven hypophagia. We examined the effect of TRP administered via intragastric gavage on energy- and palatability-induced feeding in mice. We sought to identify central mechanisms through which TRP suppresses appetite. Effects of TRP on consumption of energy-dense and energy-dilute tastants were established in mice stimulated to eat by energy deprivation or palatability. A conditioned taste aversion (CTA) paradigm was used to assess whether hypophagia is unrelated to sickness. c-Fos immunohistochemistry was employed to detect TRP-induced activation of feeding-related brain sites and of oxytocin (OT) neurons, a crucial component of satiety circuits. Also, expression of OT mRNA was assessed with real-time PCR. The functional importance of OT in mediating TRP-driven hypophagia was substantiated by showing the ability of OT receptor blockade to abolish TRP-induced decrease in feeding. TRP reduced intake of energy-dense standard chow in deprived animals and energy-dense palatable chow in sated mice. Anorexigenic doses of TRP did not cause a CTA. TRP failed to affect intake of palatable yet calorie-dilute or noncaloric solutions (10% sucrose, 4.1% Intralipid or 0.1% saccharin) even for TRP doses that decreased water intake in thirsty mice. Fos analysis revealed that TRP increases activation of several key feeding-related brain areas, especially in the brain stem and hypothalamus. TRP activated hypothalamic OT neurons and increased OT mRNA levels, whereas pretreatment with an OT antagonist abolished TRP-driven hypophagia. We conclude that intragastric TRP decreases food and water intake, and TRP-induced hypophagia is partially mediated via central circuits that encompass OT.

year: 2018

title: A dialectic analysis of the whistleblowing phenomenon

authors: Bather, Andrea

subjects: whistleblowing

abstract: Although whistleblowers are often portrayed as courageous individuals deserving of respect, the act of whistleblowing can be viewed as a disloyal act which may bring much harm to the whistleblower's colleagues. We argue that although some whistleblowers have provided a great service to society, the world would be best served if the need for external whistleblowing were obviated by appropriate management practices.

text: A dialectic analysis of the whistleblowing phenomenon Although whistleblowers are often portrayed as courageous individuals deserving of respect, the act of whistleblowing can be viewed as a disloyal act which may bring much harm to the whistleblower's colleagues. We argue that although some whistleblowers have provided a great service to society, the world would be best served if the need for external whistleblowing were obviated by appropriate management practices.

year: 2006

title: Green or grey pandemic recovery? Revealing the blue–green infrastructure influences in Aotearoa-New Zealand’s “Shovel Ready” Covid-19 response

authors: Hanna, Christina Jane

abstract: This paper analyses Aotearoa-New Zealand’s “shovel-ready fund” to assess if, and how, blue–green infrastructure systems were present in bids from its largest city regions. Findings indicate a greater prevalence in areas with existing spatial plans, and while there was some consideration of climate resilience, there was no real acknowledgement of the pandemic or human health. More positively, there was some evidence of unique indigenous influences that have potential to develop more inclusive and holistic blue–green infrastructure initiatives. The overall response, however, demonstrates a disjointed approach to blue–green infrastructure-related projects, and a missed opportunity for a more transformative response to the climate crisis and human health emergencies.

text: Green or grey pandemic recovery? Revealing the blue–green infrastructure influences in Aotearoa-New Zealand’s “Shovel Ready” Covid-19 response This paper analyses Aotearoa-New Zealand’s “shovel-ready fund” to assess if, and how, blue–green infrastructure systems were present in bids from its largest city regions. Findings indicate a greater prevalence in areas with existing spatial plans, and while there was some consideration of climate resilience, there was no real acknowledgement of the pandemic or human health. More positively, there was some evidence of unique indigenous influences that have potential to develop more inclusive and holistic blue–green infrastructure initiatives. The overall response, however, demonstrates a disjointed approach to blue–green infrastructure-related projects, and a missed opportunity for a more transformative response to the climate crisis and human health emergencies.

year: 2022