ABSTRACT
Alguns estudos sugerem que as vias opioidérgicas centrais parecem desempenhar um papel regulatório no controle da ingestão de água e sal em mamíferos. As ações dos opioides centrais sobre a regulação do controle hidroeletrolítico são mediadas por vários dos subtipos de receptores opioides. O papel dos receptores delta e kappa-opioides centrais neste processo não está adequadamente elucidado sendo necessário mais estudos que o esclareçam. Objetivo: Este estudo investigou o envolvimento dos receptores delta e kappa-opioides centrais no apetite por sódio em ratos depletados deste íon e em rato ativados centralmente com angiotensina. Material e Métodos: Foram utilizados ratos Wistar (270 ± 20 g), submetidos à cirurgia estereotáxica para implante de cânula guia no ventrículo lateral esquerdo (VL), no órgão subfornical (OSF), no núcleo preóptico mediano (MnPO) e no núcleo basolateral da amígdala (BLA). No protocolo de depleção de sódio os animais foram submetidos à injeção subcutânea de furosemida combinada com dieta hipossódica quatro dias após a cirurgia. Neste modelo de estudo os animais receberam injeção intracerebroventricular (i.c.v.) do antagonista delta-opioide naltrindole no quinto dia pós-cirúrgico, nas doses de 5, 10 e 20 nmol/2 μL e do antagonista kappa-opioide, norbinaltorfimina, injetado no OSF, MnPO e BLA, nas doses de 0,5, 1,0 e 2,0 nmol/0,2 μL...
Central opioid pathways seem to have an important role on the control of water and salt intake in mammals, and brain opioid peptides may influence hydroelectrolyte balance through a myriad of actions mediated by distinct opioid receptors. The specific role of central delta and kappa-opioid receptors (DOR and KOR) in this process is far from being fully understood. In the present work, we investigated the role of those receptors in the control of water and salt intake, in sodium-depleted rats and rats with activation central angiotensinergic. Method: Wistar male rats (250 ± 20 g) were used in the experiment after stereotaxic cannulation of the VL left, SFO, MnPO and BLA. To study the effect of the blockade of central DOR and KOR on water and salt intake in rats were sodium depleted by the concomitant use of s.c. injections of furosemide and were kept in hypossodic diet, five days after surgery. In the sixth day, they received i.c.v. injections of a selective delta-opioid receptor antagonist (naltrindole) at the doses of 5, 10 and 20 nmol/2 μL and injections in the SFO, MnPO and BLA of a selective kappa-opioid receptor antagonist (norbinaltorphimine) at the doses of 0.5, 1.0 and 2.0 nmol/0.2 μL...
Subject(s)
Animals , Appetite , Appetite/physiology , Appetite/immunology , Receptors, Opioid, delta/analysis , Receptors, Opioid, delta/classification , Receptors, Opioid, delta/isolation & purification , Receptors, Opioid, delta/metabolism , Receptors, Opioid, kappa/analysis , Receptors, Opioid, kappa/immunologyABSTRACT
Endogenous opioids participate in growth regulation. Liver regeneration relates to growth. Thus, we explored the expression of methionine enkephalin and of the delta opioid receptor 1 immunoreactivities with a polyclonal rabbit antibody in deparaffinized liver of patients with chronic liver disease. Fifteen of a total of fifty-eight samples expressed both opioid receptor and methionine enkephalin immunoreactivities, one sample expressed receptor but not methionine enkephalin immunoreactivity, and two samples expressed methionine enkephalin but not receptor immunoreactivity. Ten of the 45 (22%) samples from patients with chronic hepatitis C, four of the eight (50%) samples from patients with chronic hepatitis B, one of the five (20%) samples from patients with autoimmune hepatitis expressed both met-enkephalin and delta opioid receptor 1 immunoreactivities. The expression of methionine enkephalin and delta opioid receptor 1 immunoreactivities suggests that methionine enkephalin exerts an effect in situ, which may include regulation of liver regeneration. However, another possibility that concerns an effect of methionine enkephalin in the liver arises. As morphine, which acts via opioid receptors, has been reported to increase hepatitis C virus replication in vitro and to interfere with the antiviral effect of interferon, methionine enkephalin, analogous to morphine, may enhance the replication of the hepatitis C virus in the liver of patients with this type of viral hepatitis, and interfere with the therapeutic effect of interferon. These results may explain at least in part, why some patients with chronic hepatitis C infection do not respond to interferon therapy.