Abstract Orexins, or hypocretins, are peptides originally found in the hypothalamus, and have been shown to be involved in the stabilization and maintenance of sleep and wakefulness. In addition, these peptides are known for their actions on energy homeostasis by increased heat production or physical activity. Previous results suggest them to be also involved in peripheral actions on the regulation of intestinal secretion, depending on the subject’s nutritional status (fasted-fed). Orexin-A and Orexin-B peptides, are derived from the prepro-orexin precursor protein. These ligands bind to two G-protein-coupled receptors, orexin-1 and -2 -receptors. Despite intensive research, the role of orexins has not yet been clarified. The aim of the present study was to investigate the role of orexins and their receptors on sleep and wake patterns, energy homeostasis and intestinal secretion. The effects of orexins on sleep and wakefulness, and energy homeostasis were studied in a novel transgenic mouse line, overexpressing the human prepro-orexin gene. The overexpression of prepro-orexin and orexin-A was confirmed in the hypothalami of transgenic mice. The transgenic mice showed a significant reduction in their REM sleep during day and night time, and differences in their vigilance states in the light/dark transition periods. In addition, the mice demonstrated a significantly elevated day time food intake at room temperature, and an increased metabolic heat production independent of uncoupling protein 1 mediated thermogenesis in brown adipose tissue. Instead, transgenic mice showed increased levels of uncoupling protein 2 in white adipose tissue. Furthermore, transgenic mice significantly decreased their total locomotor activity during the first two nights in response to cold exposure (+4°C). The effect of orexins and their receptors on duodenal HCO3– secretion were studied after an overnight (16 h) food deprivation in an in situ perfused organ. Fasting decreased the expression of orexin receptors in rat duodenal mucosa and in acutely isolated duodenal enterocytes. Furthermore, food deprivation abolished OXA induced duodenal mucosal HCO3– secretion in rats, and intracellular calcium signalling in isolated rat and human duodenal enterocytes. In conclusion, the present thesis demonstrates that orexins inhibit REM sleep. In addition, peptides affect increasingly on metabolic heat production, independent of uncoupling protein 1 mediated thermogenesis. Furthermore, the orexin system has a significant role in duodenal bicarbonate secretion, which is regulated by the presence of food in the intestine.

Eating disorders are serious psychological disorders associated with debilitating lifestyle, multiple health problems and high rates of suicidality and mortality. Despite extensive research, the aetiology of eating disorders still remains unclear. Amongst the identified risk factors for eating disorders, stress has been frequently studied. The purpose of the present study was to explore the possibility that tail-pinch administered to rats could provide an animal model of stress-induced eating disturbances in humans, and whether environmental enrichment might ameliorate the effects of stress. In Experiment 1, we compared eating behaviours of rats that were reared in either enriched or standard environments and later exposed to tail-pinch and allowed to eat when food deprived. The study showed that a single exposure to tail-pinch induced eating disturbances in most of the rats. When rats were not food deprived, but were conditioned to eating when placed in test chamber, tail-pinch suppressed eating in all rats, but significantly more for rats reared under standard than in enriched conditions. Experiment 2 used a between-subjects design in which rats were reared in either a standard or enriched environment, and were either exposed to tail-pinch or not exposed during sessions in which they were not food deprived and allowed to eat. Tail-pinch suppressed the food intake of rats reared in enriched but not standard environments. Although this finding appeared to contradict results of Experiment 1, analysis of body weight revealed that exposure to tail pinch suppressed increases in weight gain across sessions more for rats reared in standard than enriched environments. The suppression of food intake during test sessions for enriched but not standard rats exposed to tail-pinch was attributed to differences in contextual conditioning and discrimination of the test chamber from home cages. Overall, results of the present study suggest that rats reared in enriched environments were more resilient to the effects of tail-pinch as a stressor. Implications of these findings for the understanding of human eating disorders are discussed.

A descoberta de aminopeptidase regulada por insulina (IRAP), a qual hidrolisa peptídeos como ocitocina e vasopressina e é receptora de angiotensina IV, destaca a importância do estudo do envolvimento de peptidases na função endócrina do adipócito. Estudos recentes detectaram alterações das atividades de aminopeptidase neutra e de dipeptidil peptidase IV (DPPIV) no plasma e no hipotálamo e hipocampo na obesidade induzida por glutamato monossódico (MSG). A presente tese propôs (i) a existência de atividades aminopeptidásicas ácida (APA), básica (APB), neutra insensível (APM) e sensível à puromicina (PSA), metionil (MetAP) e DPPIV, além da já conhecida (leucil (LAP)/cistil (CAP)/IRAP), nas frações de membrana plasmática (FM) e de alta (HDM) e baixa (LDM) densidade microssomal de adipócitos isolados do depósito de gordura retroperitoneal; (ii) que suas atividades catalíticas, expressões gênicas e tráfego subcelular seriam diferenciados entre obesos induzidos por MSG, submetidos ou não à privação alimentar e em animais controle sadios, submetidos ou não a privação alimentar; (iii) e influenciadas por insulina, angiotensina II, angiotensina IV e vasopressina. A existência de todas essas aminopeptidases no adipócito foi demonstrada, sendo a APM a que apresenta maior Vmax e maior eficiência catalítica e a APA a maior afinidade. Os animais obesos apresentaram aumento do diâmetro médio dos adipócitos e aumento do lipócrito, caracterizando hipertrofia adipocítica, enquanto os controles privados de alimento tiveram um aumento no número de adipócitos e aumento no lipócrito, caracterizando hiperplasia adipocítica. Pela primeira vez, um perfil variado de atividades aminopeptidásicas distribuídas em diferentes compartimentos subcelulares do adipócito é evidenciado juntamente com a demonstração de diferenças no padrão de distribuição destas atividades entre os ratos obesos e sadios, privados ou não de alimento. Dentre as novas aminopeptidases detectadas no adipócito não há nenhuma com a característica clássica de IRAP. No geral, as alterações das atividades catalíticas nas diferentes situações sob estudo mostram o envolvimento dessas novas aminopeptidases na regulação endócrina do balanço energético (provavelmente via ação hidrolítica sobre angiotensina II e vasopressina) sob modulação por angiotensina IV (APB, APM, DPPIV, LAP/IRAP, MetAP e PSA em animais controle sadios e APB em animais controle privados de alimento), angiotensina II (APB e PSA nos animais obesos) e vasopressina (APB nos animais obesos privados de alimento; e influenciadas em seu tráfego subcelular por angiotensina II (CAP, DPPIV e LAP/IRAP) e angiotensina IV (LAP/IRAP). O tráfego subcelular da conhecida atividade CAP/IRAP mostrou-se suscetível à insulina e vasopressina / The discovery of insulin-regulated aminopeptidase (IRAP), which hydrolyzes peptides such as oxytocin and vasopressin and is an angiotensin IV receptor, highlights the importance of the involvement of peptidases in the endocrine function of adipocyte. Recent studies have detected changes in aminopeptidase activities of neutral aminopeptidase and dipeptidyl peptidase IV (DPPIV) in the plasma and in the hypothalamus and hippocampus of rats with obesity induced by monosodium glutamate (MSG). The present thesis proposes (i) the existence of acid (APA), basic (APB), neutral insensitive (APM) and puromycin sensitive (PSA) aminopeptidases, methionyl aminopeptidase (MetAP) and dipeptidyl peptidase IV (DPPIV), besides the well-known cystyl (CAP) / leucine aminopeptidase (LAP) / IRAP) in plasma membrane (MF) and in high (HDM) and low (LDM) density microsomes of isolated adipocytes from retroperitoneal fat pad; (ii) that their catalytic activities, gene expression and subcellular trafficking were different among MSG-induced obese and healthy control rats (food deprived or not); (iii) and influenced by insulin, angiotensin II and IV, and vasopressin. The existence of all these adypocite aminopeptidases was demonstrated. APM has a highest Vmax and catalytic efficiency, while APA has a highest substrate affinity. The obese animals have increased mean diameter of adipocytes and lipocrit, characterizing hypertrophy, while the food deprived rats had an increased number of adipocytes and lipocrit, characterizing hyperplasia. For the first time, a profile of varied aminopeptidases activities distributed in different subcellular compartments of adipocyte is evidenced together with the demonstration of differences in the distribution pattern of these activities among the obese and healthy rats, food deprived or not. Among these novel aminopeptidases detected in adipocytes there is no one with the classical characteristic of IRAP. In general, changes on catalytic activities in these different situations show the involvement of these novel aminopeptidases in the endocrine regulation of energy balance (probably via hydrolytic action on angiotensin II and vasopressin) under modulation by angiotensin IV (APB, APM, DPPIV, LAP/IRAP, MetAP and PSA in healthy animals and APB in food deprived healthy animals), by angiotensin II (APB and PSA in obese) and by vasopressin (APB in food deprived obese animais); and under influence of by angiotensin II (CAP, DPPIV, LAP/IRAP) and angiotensin IV (LAP/IRAP) on their subcellular trafficking. Subcellular trafficking of the well-known CAP/IRAP was susceptible to insulin and vasopressin

INTRODUÇÃO:A neuraminidase 1 (chamada a seguir por Neu1) regula o catabolismo de sialoglicoconjugados nos lisossomos. A deficiência congênita da Neu1 é a base da sialidose, doença neurossomática grave associada a deformidades osteoesqueléticas, hipotonia e fraqueza muscular. Camundongos com deficiência de Neu1 desenvolvem uma forma atípica de degeneração muscular caracterizada porproliferação anormal de fibroblastoslevando a invasão nas fibras musculares, expansão da matriz extracelular (MEC), fragmentação do citoplasma, formação vacuolar e atrofia muscular. A ocorrência de atrofia muscular indica que a deficiência da Neu1 podeestar relacionada com o controle da massa muscular, a qual é dependente do equilíbrio entre síntese e degradação proteica.Uma característica principalnaMacroautofagia (denominada a seguir por autofagia) é a principal via de degradação intracelular sendo expressamente essencial para a homeostase celular e remoção de materiais citoplasmáticos. Objetivos: Avaliarseos efeitos da deficiência da Neuraminidase 1 afetama indução de autofagia e a formação de autofagossomos e determinar os efeitos do bloqueio da função lisossomal sobre o fenótipo muscular na deficiência da Neuraminidase1.Metodologia:Camundongos Neu1+/-foram cruzados e os filhotes genotipados, onde camundongos Neu1-/-(nocaute) e Neu1+/+(normal),foram utilizados no estudon total=90, sendo 10 em padronizações, 20 para coleta de fibroblastos e 60 para procedimentos in vivo, os grupos experimentais foram divididos em privação alimentar por 2 dias que, por meio da inibição do mTOR, induz a autofagia;grupo detratamento com Colchicina por 4 dias onde irá impedir a junção autofagossomo/lisossomonão havendo a degradaçãolisossomaleadicionado nos dois últimos dias de privação alimentar e o grupo de tratamento comRapamicina por 7 dias, droga com função de inibir seletivamente o mTOR.Após os tratamentos, os animais foram eutanasiadospara coleta dos músculos gastrocnêmios e tibiais anterior. Os músculos foram analisados apósas coloraçõeshistológicas porHematoxilina & Eosina e Fosfatase Ácida; Imunofluorescência de LC3-I/II; Western Blottingdas proteínas LC3-I/II, Lamp-1 e p62/SQSTM e a análise Ultra-estrutural. Além disso, foi realizada cultura de fibroblastos, os quais foram submetidos à privação de nutrientes e ao tratamento com Rapamicina, seguidos dasmesmas metodologias de análise invivo. Resultados:As análises histológicas através de H&E e Fosfatase Ácida não revelaram alterações consistentes na musculatura esquelética de animais submetidos aos tratamentos, mostrando em animais com deficiência de Neu1 um aumento anormal do espaço endomisial, e aumento da atividade lisossomalintracitoplasmáticos. Na análise ultra-estruturalobservou-se em todos os grupos, a presença de diversas estruturas com aspecto autofágico, de diferentes tamanhos, formas e constituintes. Naanálise da expressão do LC3 através de Western Blottingmostrou importante ativação do LC3-II na privação alimentar (com e sem administração de Colchicina) tanto em animais controles quanto em animais com deficiência de Neu1 e uma importante ativação do LC3-I em Rapamicina em ambos os grupos mostrando assim que houve um aumento da via da autofagia através do bloqueio do mTOR. Já na análise de Imunofluorescência não foi possível observar diferença consistenteentre os grupos.A análise in vitrode Western Blottingmostrou que tal ativação foi similar entre fibroblastos Neu1+/+e Neu1-/-. Conclusão:Os experimentos relacionados com a ativação ou inibição da autofagia, não resultaram em diferenças consideráveis entre músculos normais e músculos com deficiência de Neu1. Desta forma, podemos concluir com estes experimentos que aparentemente a Neu1, apesar de ser uma importante enzima lisossomal, não interfere com o processo de autofagia / Introduction:Neuraminidase 1 (hereinafter Neu1) regulates the catabolism of sialoglycoconjugates in lysosomes. The congenital deficiency of Neu1 is the basis of sialidosis, a severe neurosomatic disease associated with osteo-skeletal deformities, hypotonia, and muscle weakness. Mice with Neu1deficient develop an atypical form of muscle degeneration characterized by abnormal fibroblast proliferation leading to muscle fiber invasion, extracellular matrix expansion (ECM), cytoplasm fragmentation, vacuolar formation, and muscle atrophy. The occurrence of muscle atrophy indicates that deficiencyofNeu1 may be related to the control of muscle mass, which is dependent on the balance between synthesis and protein degradation. A major feature in Macroautophagy (hereinafter referred to as autophagy) is the main pathway of intracellular degradation being expressly essential for cellular homeostasis and removal of cytoplasmic materials. Objectives:To evaluate whether the effects of neuraminidase 1 deficiency affect autophagy induction and autophagosome formation and to determine the effects of lysosomal function block on muscle phenotype in neuraminidase 1 deficiency. Methodos:Mice Neu1+/-were crossbred and the genotyped pups, where mice Neu1-/-(knockout) and Neu1+/+(normal), were used in the study ntotal = 90, 10 for standardization, 20 for fibroblast collection and 60 for in vivo procedures, experimental groups were divided into food deprivation for 2 days that, through mTOR inhibition, induces autophagy; Colchicine treatment group for 4 days whereit will prevent autophagosome/lysosome junction without lysosomal degradation and added in the last two days of food deprivation and Rapamycin treatment group for 7 days, drug with function to selectively inhibit mTOR. After the treatments, the animals were euthanized to collect the anterior gastrocnemius and tibial muscles. The muscles were analyzed after histological staining by Hematoxylin & Eosin and Acid Phosphatase; LC3-I/II immunofluorescence; Western Blottingof LC3-I/II, Lamp-1 and p62/SQSTM proteins and Ultra-structural analysis. In addition, fibroblasts were cultured and subjected to nutrient deprivation and Rapamycin treatment, followed by the same in vivo analysis methodologies. Results:Histological analyzes by H&E and Acid Phosphatase did notreveal consistent changes in skeletal muscle of animals submitted to treatments, showing in animals with Neu1 deficiency an abnormal increase in endomysial space and increased intracytoplasmic lysosomal activity.In ultrastructural analysis, it was observed in all groups, the presence of several structures with autophagic aspect, of different sizes, shapes and constituents. The analysis of LC3 expression by Western Blottingshowed important activation of LC3-II in food deprivation (with and without Colchicine administration) in both control and Neu1 deficient animals and an important activation of LC3-I in Rapamycininboth groups,thus showing an increase in the autophagy pathway through mTOR blockade. In the immunofluorescence analysis, it was not possible to observe consistent difference between the groups. In vitro Western Blottinganalysis showed that such activation was similar between Neu1+/+and Neu1-/-fibroblasts. Conclusion: Experiments related to activation or inhibition of autophagy did not result in considerable differencesbetween normal muscles and Neu1 deficient muscles. Thus, we can conclude from these experiments that apparently Neu1, despite being an important lysosomal enzyme, does not interfere with the autophagy process

Cholinergic inputs from mesopontine tegmentum activate midbrain dopamine (DA) neurons via M5 muscarinic receptors. The M5 receptor is important for mesopontine stimulation-induced accumbal or striatal DA efflux, brain stimulation reward or morphine-induced conditioned place preference (CPP). M5 receptor knockout (KO) mice show 40-50% less morphine-induced locomotion. Pedunculopontine tegmental nucleus (PPT) lesions in rodents block morphine CPP, but are ineffective after 18 hours food deprivation, opiate dependence, or intra-VTA BDNF. Based on these findings, we investigated whether acute food deprivation or intra-VTA BDNF alters morphine-induced locomotion (3 and 10 mg/kg, i.p.) in C57BL/6 M5 KO mice. Non-deprived M5 KOs showed reduced morphine-induced locomotion, suggesting M5 receptors partly mediate morphine-induced locomotion. Morphine-induced locomotion was reversed in food-deprived mice, suggesting the stimulant effects of morphine were altered to bypass the PPT. Unexpectedly, intra-VTA BDNF infusions were ineffective in altering morphine-induced locomotion. Additionally, M5 KOs receiving intra-VTA saline showed no deficits in morphine-induced locomotion.

Cholinergic inputs from mesopontine tegmentum activate midbrain dopamine (DA) neurons via M5 muscarinic receptors. The M5 receptor is important for mesopontine stimulation-induced accumbal or striatal DA efflux, brain stimulation reward or morphine-induced conditioned place preference (CPP). M5 receptor knockout (KO) mice show 40-50% less morphine-induced locomotion. Pedunculopontine tegmental nucleus (PPT) lesions in rodents block morphine CPP, but are ineffective after 18 hours food deprivation, opiate dependence, or intra-VTA BDNF. Based on these findings, we investigated whether acute food deprivation or intra-VTA BDNF alters morphine-induced locomotion (3 and 10 mg/kg, i.p.) in C57BL/6 M5 KO mice. Non-deprived M5 KOs showed reduced morphine-induced locomotion, suggesting M5 receptors partly mediate morphine-induced locomotion. Morphine-induced locomotion was reversed in food-deprived mice, suggesting the stimulant effects of morphine were altered to bypass the PPT. Unexpectedly, intra-VTA BDNF infusions were ineffective in altering morphine-induced locomotion. Additionally, M5 KOs receiving intra-VTA saline showed no deficits in morphine-induced locomotion.

Eating disorders are serious psychological disorders associated with debilitating lifestyle, multiple health problems and high rates of suicidality and mortality. Despite extensive research, the aetiology of eating disorders still remains unclear. Amongst the identified risk factors for eating disorders, stress has been frequently studied. The purpose of the present study was to explore the possibility that tail-pinch administered to rats could provide an animal model of stress-induced eating disturbances in humans, and whether environmental enrichment might ameliorate the effects of stress. In Experiment 1, we compared eating behaviours of rats that were reared in either enriched or standard environments and later exposed to tail-pinch and allowed to eat when food deprived. The study showed that a single exposure to tail-pinch induced eating disturbances in most of the rats. When rats were not food deprived, but were conditioned to eating when placed in test chamber, tail-pinch suppressed eating in all rats, but significantly more for rats reared under standard than in enriched conditions. Experiment 2 used a between-subjects design in which rats were reared in either a standard or enriched environment, and were either exposed to tail-pinch or not exposed during sessions in which they were not food deprived and allowed to eat. Tail-pinch suppressed the food intake of rats reared in enriched but not standard environments. Although this finding appeared to contradict results of Experiment 1, analysis of body weight revealed that exposure to tail pinch suppressed increases in weight gain across sessions more for rats reared in standard than enriched environments. The suppression of food intake during test sessions for enriched but not standard rats exposed to tail-pinch was attributed to differences in contextual conditioning and discrimination of the test chamber from home cages. Overall, results of the present study suggest that rats reared in enriched environments were more resilient to the effects of tail-pinch as a stressor. Implications of these findings for the understanding of human eating disorders are discussed.

A descoberta de aminopeptidase regulada por insulina (IRAP), a qual hidrolisa peptídeos como ocitocina e vasopressina e é receptora de angiotensina IV, destaca a importância do estudo do envolvimento de peptidases na função endócrina do adipócito. Estudos recentes detectaram alterações das atividades de aminopeptidase neutra e de dipeptidil peptidase IV (DPPIV) no plasma e no hipotálamo e hipocampo na obesidade induzida por glutamato monossódico (MSG). A presente tese propôs (i) a existência de atividades aminopeptidásicas ácida (APA), básica (APB), neutra insensível (APM) e sensível à puromicina (PSA), metionil (MetAP) e DPPIV, além da já conhecida (leucil (LAP)/cistil (CAP)/IRAP), nas frações de membrana plasmática (FM) e de alta (HDM) e baixa (LDM) densidade microssomal de adipócitos isolados do depósito de gordura retroperitoneal; (ii) que suas atividades catalíticas, expressões gênicas e tráfego subcelular seriam diferenciados entre obesos induzidos por MSG, submetidos ou não à privação alimentar e em animais controle sadios, submetidos ou não a privação alimentar; (iii) e influenciadas por insulina, angiotensina II, angiotensina IV e vasopressina. A existência de todas essas aminopeptidases no adipócito foi demonstrada, sendo a APM a que apresenta maior Vmax e maior eficiência catalítica e a APA a maior afinidade. Os animais obesos apresentaram aumento do diâmetro médio dos adipócitos e aumento do lipócrito, caracterizando hipertrofia adipocítica, enquanto os controles privados de alimento tiveram um aumento no número de adipócitos e aumento no lipócrito, caracterizando hiperplasia adipocítica. Pela primeira vez, um perfil variado de atividades aminopeptidásicas distribuídas em diferentes compartimentos subcelulares do adipócito é evidenciado juntamente com a demonstração de diferenças no padrão de distribuição destas atividades entre os ratos obesos e sadios, privados ou não de alimento. Dentre as novas aminopeptidases detectadas no adipócito não há nenhuma com a característica clássica de IRAP. No geral, as alterações das atividades catalíticas nas diferentes situações sob estudo mostram o envolvimento dessas novas aminopeptidases na regulação endócrina do balanço energético (provavelmente via ação hidrolítica sobre angiotensina II e vasopressina) sob modulação por angiotensina IV (APB, APM, DPPIV, LAP/IRAP, MetAP e PSA em animais controle sadios e APB em animais controle privados de alimento), angiotensina II (APB e PSA nos animais obesos) e vasopressina (APB nos animais obesos privados de alimento; e influenciadas em seu tráfego subcelular por angiotensina II (CAP, DPPIV e LAP/IRAP) e angiotensina IV (LAP/IRAP). O tráfego subcelular da conhecida atividade CAP/IRAP mostrou-se suscetível à insulina e vasopressina / The discovery of insulin-regulated aminopeptidase (IRAP), which hydrolyzes peptides such as oxytocin and vasopressin and is an angiotensin IV receptor, highlights the importance of the involvement of peptidases in the endocrine function of adipocyte. Recent studies have detected changes in aminopeptidase activities of neutral aminopeptidase and dipeptidyl peptidase IV (DPPIV) in the plasma and in the hypothalamus and hippocampus of rats with obesity induced by monosodium glutamate (MSG). The present thesis proposes (i) the existence of acid (APA), basic (APB), neutral insensitive (APM) and puromycin sensitive (PSA) aminopeptidases, methionyl aminopeptidase (MetAP) and dipeptidyl peptidase IV (DPPIV), besides the well-known cystyl (CAP) / leucine aminopeptidase (LAP) / IRAP) in plasma membrane (MF) and in high (HDM) and low (LDM) density microsomes of isolated adipocytes from retroperitoneal fat pad; (ii) that their catalytic activities, gene expression and subcellular trafficking were different among MSG-induced obese and healthy control rats (food deprived or not); (iii) and influenced by insulin, angiotensin II and IV, and vasopressin. The existence of all these adypocite aminopeptidases was demonstrated. APM has a highest Vmax and catalytic efficiency, while APA has a highest substrate affinity. The obese animals have increased mean diameter of adipocytes and lipocrit, characterizing hypertrophy, while the food deprived rats had an increased number of adipocytes and lipocrit, characterizing hyperplasia. For the first time, a profile of varied aminopeptidases activities distributed in different subcellular compartments of adipocyte is evidenced together with the demonstration of differences in the distribution pattern of these activities among the obese and healthy rats, food deprived or not. Among these novel aminopeptidases detected in adipocytes there is no one with the classical characteristic of IRAP. In general, changes on catalytic activities in these different situations show the involvement of these novel aminopeptidases in the endocrine regulation of energy balance (probably via hydrolytic action on angiotensin II and vasopressin) under modulation by angiotensin IV (APB, APM, DPPIV, LAP/IRAP, MetAP and PSA in healthy animals and APB in food deprived healthy animals), by angiotensin II (APB and PSA in obese) and by vasopressin (APB in food deprived obese animais); and under influence of by angiotensin II (CAP, DPPIV, LAP/IRAP) and angiotensin IV (LAP/IRAP) on their subcellular trafficking. Subcellular trafficking of the well-known CAP/IRAP was susceptible to insulin and vasopressin

本研究操弄受試的食物剝奪程度以及鋰鹽（LiCl）去價值程序，觀察此兩種實驗操弄對於大白鼠舔舐行為的影響，以探討飢餓驅力調節完結行為的機制。實驗一連續觀察8天大白鼠舔舐15%蔗糖液的表現，結果顯示初期兩天剝奪受試和自由吃食受試的舔舐表現並沒有顯著差異，第三天起剝奪組才顯著高於自由吃食組。實驗二待大白鼠習於食物剝奪狀態下舔舐15%蔗糖液之後，進行僅舔舐空管的消除情境測試。實驗結果顯示將剝奪狀態改為自由吃食，不論有無接受誘因學習都不能降低受試舔舐空管的表現。實驗三則待大白鼠習於食物剝奪狀態下舔舐25%蔗糖液之後，接受空管測試（實驗三A、B、C）與舔水消除情境測試（實驗三B、C）。實驗三結果如同實驗二，將剝奪狀態改為自由吃食，不論有無接受誘因學習都不能降低受試舔舐空管或舔水的表現。實驗四使用柳橙香料配加蔗糖液（20%）進行舔舐訓練，以僅含柳橙香料水進行消除情境測試。實驗結果顯示受試不論是由剝奪狀態轉為自由吃食，或由自由吃食轉為剝奪，都顯示出當驅力高舔舐表現高或驅力低表現低的現象。實驗五進行鋰鹽去價值實驗，大白鼠先擁有舔飲柳橙香料糖精液（實驗五A）或草莓香料食鹽水（實驗五B）的經驗後，再進行鋰鹽去價值程序。實驗結果顯示大白鼠唯有舔舐香料糖精液或香料食鹽水後接受鋰鹽注射才能降低其舔舐香料水的表現；糖精－鋰鹽配對、糖精－鋰鹽配對後再舔飲一次糖精液，以及香料水－鋰鹽配對都無法降低受試舔飲香料水的表現。糖精或食鹽水只要和鋰鹽配對過，便能產生味覺嫌惡。本研究結論如下：（1）飢餓驅力調節舔舐行為的能力只顯現在舔飲蔗糖液以及舔舐柳橙香料水的消除情境測試中；（2）香料與糖精或香料與食鹽必須同時呈現與鋰鹽配對才能降低香料引發舔舐行為的能力。 / The effects of food deprivation and lithium chloride (LiCl)-induced devaluation on licking behavior were studied for the regulatory mechanism of hunger drive on licking behavior. The first experiment for measuring the licking of 15% sucrose solution for 8 days and found that deprived subjects did not lick more than non-deprived ones until the third day. In the second experiment, the rats trained to lick 15% sucrose in a food-deprivation state were shifted to a non-deprivation state and tested under extinction procedure by using the empty tube. This shift in deprivation did not suppress licking in empty tube test for subjects with or without incentive learning experiences. In the third experiment, the rats trained to lick 25% sucrose in a food-deprivation state were shifted to a non-deprivation state and tested in empty tube (Exp. 3A, B, C) or water-licking test (Exp. 3B, C) conditions. Independent of incentive learning, the shift in deprivation did not suppress licking in these two kinds of extinction conditions although the concentration of sucrose was increased. In the fourth experiment, rats were trained to lick 20% sucrose mixed with orange flavor and tested in orange flavor water-licking test condition. Deprived rats licked more than non-deprived ones in the test condition whether they were trained under deprivation or non-deprivation. In the fifth experiment, rats were trained to lick orange flavor saccharin solution (Exp. 5A) or strawberry flavor sodium chloride (NaCl) solution (Exp. 5B) and then tested by the LiCl devaluation procedure. Flavored saccharin or flavored NaCl paired with LiCl suppressed rats to lick flavored water. But none of saccharin paired with LiCl, incentive learning after saccharin devaluation, and flavored water paired with LiCl had any significant effect. Saccharin or NaCl paired with LiCl could induce taste aversion. In conclusion, hunger drive modulating licking behavior was only found in licking sucrose or the flavored water-licking test condition. Further, only flavored saccharin or flavored NaCl solutions paired with LiCl could suppress licking flavored water.

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