Overfeeding, Autonomic Regulation and Metabolic Consequences

The autonomic nervous system plays an important role in the regulation of body processes in health and disease. Overfeeding and obesity (a disproportional increase of the fat mass of the body) are often accompanied by alterations in both sympathetic and parasympathetic autonomic functions. The overfeeding-induced changes in autonomic outflow occur with typical symptoms such as adiposity and hyperinsulinemia. There might be a causal relationship between autonomic disturbances and the consequences of overfeeding and obesity. Therefore studies were designed to investigate autonomic functioning in experimentally and genetically hyperphagic rats. Special emphasis was given to the processes that are involved in the regulation of peripheral energy substrate homeostasis. The data revealed that overfeeding is accompanied by increased parasympathetic outflow. Typical indices of vagal activity (such as the cephalic insulin release during food ingestion) were increased in all our rat models for hyperphagia. Overfeeding was also accompanied by increased sympathetic tone, reflected by enhanced baseline plasma norepinephrine (NE) levels in both VMH-lesioned animals and rats rendered obese by hyperalimentation. Plasma levels of NE during exercise were, however, reduced in these two groups of animals. This diminished increase in the exercise-induced NE outflow could be normalized by prior food deprivation. It was concluded from these experiments that overfeeding is associated with increased parasympathetic and sympathetic tone. In models for hyperphagia that display a continuously elevated nutrient intake such as the VMH-lesioned and the overfed rat, this increased sympathetic tone was accompanied by a diminished NE response to exercise. This attenuated outflow of NE was directly related to the size of the fat reserves, indicating that the feedback mechanism from the periphery to the central nervous system is altered in the overfed state.

Ablation of capsaicin-sensitive afferent nerves affects insulin response during an intravenous glucose tolerance test

We investigated the role of sensory nerves in glucose tolerance in conscious Wistar rats neonatally treated with neurotoxin capsaicin or vehicle. Intravenous glucose tolerance tests (IVGTT, 150, 300 and 450 mg in 30 min) were performed to measure glucose tolerance, and glucose, insulin and glucagon levels were measured. Higher glucose concentration resulted in a greater insulin response in both capsaicin- and vehicle-treated rats. However, glucose-stimulated insulin secretion was attenuated in capsaicin-treated animals, even though glucose levels did not differ. Glucagon levels did not differ between both groups. These results show that capsaicin-sensitive nerves are involved in glucose-stimulated insulin secretion, but are not directly involved in the regulation of blood glucose levels. Moreover, they suggest that capsaicin-sensitive nerves could be involved in the regulation of insulin sensitivity. We hypothesize that sensory afferents could play a role in the aetiology of pathologies where glucohomeostatic mechanisms are disturbed, as is in type 2 diabetes mellitus. (c) 2005 Elsevier Inc. All rights reserved

Effects of MCH and a MCH1-receptor antagonist on (palatable) food and water intake

Melanin concentrating hormone (MCH) is a regulator of ingestive behavior, but several issues regarding its effects on specific components of ingestive behavior remain to be elucidated. Therefore, we injected, in the 3rd ventricle of male Wistar rats, saline, MCH (5 mu g), MCH (5 mu g) together with a MCH1-R antagonist (A, 10 mu g) and the antagonist alone (A, 10 mu g). Our results show that (1) central administration of MCH stimulates food intake (lab chow and medium high fat diet) and this can be blocked by a MCH1-R antagonist; (2) the MCH-induced increase in food intake is mediated through increased meal number, meal duration and meal size; (3) the MCH1-R antagonist is able to significantly reduce the intake of a highly palatable food (condensed sweet milk) and is more effective in blocking MCH-induced food intake when rats are fed a palatable medium high fat food; and (4) MCH stimulated water intake independently from and disproportionately to food intake. In conclusion, our results point to an involvement of endogenous MCH in the enhanced intake of palatable food. Furthermore, they confirm that MCH stimulates not only food intake but also water intake. (c) 2005 Elsevier B.V. All rights reserved

DARE TO ASK! Suicidal patients’ experiences of nurses’ treatment

Introduktion Varje år begås ca 1500 självmord och 20000 självmordsförsök. Som sjuksköterska kommer man med stor sannolikhet att vårda självmordsnära patienter. Patienterna kan reagera på olika sätt och att som sjuksköterska bemöta dem på ett bra sätt är många gånger svårt. Travelbees teorier kan då vara ett gott stöd för sjuksköterskan. Syfte Att belysa hur patienter upplever att de har blivit bemötta av sjuksköterskan efter ett självmordsförsök för att få vägledning i vad som är ett gott bemötande. Metod Litteraturstudie av artiklar sökta och funna via databasen Cinahl med sökorden suicide attempt, patients´ perspective och nursing care. Resultat Det huvudtema som framträdde var bemötande. Därtill hörde underrubrikerna lyhördhet, stöd, kommunikation och bekräftelse med ytterligare tillhörande begrepp. De var väl överrensstämmande med Travelbees begreppsvärld. Sjuksköterskan fyller en viktig funktion och kan med sitt bemötande avgöra om patientens behandling ska lyckas eller inte. Diskussion Det är bara patienten som kan avgöra om sjuksköterskans bemötande är gott eller inte, men är man som sjuksköterska professionell i sitt bemötande blir de allra flesta patienter nöjda. Tyvärr verkar det dock som om mången sjuksköterska räds att närma sig en självmordsnära patient. Göteborgs Universitet bör utbilda sjuksköterskestudenterna mer i att inte vara rädda för att närma sig det som är svårt. Liksom Travelbee anser vi att sjuksköterskans människosyn avspeglas i hur patienterna tas omhand. Konklusion Det är viktigt att våga vara nära självmordsnära patienter – att våga fråga. Att ha en teori/modell att utgå ifrån i sin sjuksköterskeroll underlättar