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: Factors affecting employer adoption of drug testing in New Zealand

authors: Haar, Jarrod M.

subjects: employee drug testing

abstract: This paper explores employer attitudes towards drug testing in New Zealand to establish under what conditions adoption may be encouraged or discouraged. A survey of 162 New Zealand employers found that adoption rates of drug testing policies were low at 6 per cent. Exploring predictors of the likelihood of drug testing adoption in the next year found that firms that are more compliant to institutional pressures were more likely to seek adoption, as were firms that perceived positive benefits from adoption. Further, firms that perceived negative effects from drug testing, such as union pressures, were less likely to adopt drug testing in the future. Additionally, the moderating effects of organisational size was explored, and significantly affected likely adoption rates, with larger firms being more influenced by institutional pressures and positive effects. However, there was no significant moderation effect towards negative effects of drug testing, which remained strongly negative irrespective of organisational size.

text: Factors affecting employer adoption of drug testing in New Zealand This paper explores employer attitudes towards drug testing in New Zealand to establish under what conditions adoption may be encouraged or discouraged. A survey of 162 New Zealand employers found that adoption rates of drug testing policies were low at 6 per cent. Exploring predictors of the likelihood of drug testing adoption in the next year found that firms that are more compliant to institutional pressures were more likely to seek adoption, as were firms that perceived positive benefits from adoption. Further, firms that perceived negative effects from drug testing, such as union pressures, were less likely to adopt drug testing in the future. Additionally, the moderating effects of organisational size was explored, and significantly affected likely adoption rates, with larger firms being more influenced by institutional pressures and positive effects. However, there was no significant moderation effect towards negative effects of drug testing, which remained strongly negative irrespective of organisational size.

year: 2007

title: Report on the bicultural symposium at conference

authors: Masters-Awatere, Bridgette

subjects: Maori

abstract: Kia ora koutou. I decided to submit the current paper as a way to say thank you to the large group of people in attendance at the bicultural stream at the national conference in late August that was held at Waikato University. It was their continued presence and participation that served as a catalyst and motivator for this paper. I'm conscious that while there was a large number of people in the symposium, there were other streams occurring at the same time, so I thought giving an overview of the success of the symposium would be a good way to let people know who the symposium went. However, before talking specifically about the symposium, I'd like to give mention to other events of the day...

text: Report on the bicultural symposium at conference Kia ora koutou. I decided to submit the current paper as a way to say thank you to the large group of people in attendance at the bicultural stream at the national conference in late August that was held at Waikato University. It was their continued presence and participation that served as a catalyst and motivator for this paper. I'm conscious that while there was a large number of people in the symposium, there were other streams occurring at the same time, so I thought giving an overview of the success of the symposium would be a good way to let people know who the symposium went. However, before talking specifically about the symposium, I'd like to give mention to other events of the day...

year: 2007