RESUMO
The aim of the present study was to determine whether dehydroleucodine, xanthatin and 3-benzyloxymethyl-5H-furan-2-one inhibit the activation of human leukemic LAD2 mast cells induced by compound 48/80 or the calcium ionophore A23187. LAD2 cells were preincubated in the presence of test drugs and then challenged with the secretagogues. This study provides the first evidence in favor of the view that dehydroleucodine and xanthatin inhibit the degranulation of LAD2 cells, thus acting as human mast cell stabilizers. These molecules could be effective in the treatment of human diseases associated with inappropriate mast cell activation.
Assuntos
Furanos/farmacologia , Lactonas/farmacologia , Mastócitos/metabolismo , Sesquiterpenos/farmacologia , Calcimicina/farmacologia , Ionóforos de Cálcio/farmacologia , Degranulação Celular/efeitos dos fármacos , Linhagem Celular Tumoral , Humanos , Cinética , Leucemia de Mastócitos/metabolismo , Leucemia de Mastócitos/patologia , Mastócitos/fisiologia , Mastócitos/ultraestrutura , Microscopia Eletrônica de Varredura , Microscopia Eletrônica de Transmissão , beta-N-Acetil-Hexosaminidases/metabolismo , p-Metoxi-N-metilfenetilamina/farmacologiaRESUMO
The present study was designed to examine the effects of a sesquiterpene lactone isolated from Artemisia douglasiana Besser (dehydroleucodine), a xanthanolide sesquiterpene isolated from Xanthium cavanillesii Schouw (xanthatin) and a semisynthetic butenolide (3-benzyloxymethyl-5H-furan-2-one) on mast cell degranulation induced by compound 48/80. Peritoneal mast cells from male adult Sprague-Dawley rats were purified in Percoll, preincubated in the presence of test lactones (dehydroleucodine, xanthatin or 3-benzyloxymethyl-5H-furan-2-one) and then challenged with the mast cell activator compound 48/80 (10 microg/ml). Concentration-response and kinetic studies of mast cell serotonin release evoked by compound 48/80, evaluation of mast cell viability and morphology by light and electron microscopy, and comparative studies using ketotifen and sodium chromoglycate were carried out. Serotonin release studies, carried out together with morphological studies, showed the effectiveness of the above lactones to stabilize mast cells. The comparative study with ketotifen and sodium chromoglycate, well known mast cell stabilizers, showed the following order of potency dehydroleucodine=xanthatin>3-benzyloxymethyl-5H-furan-2-one> or =ketotifen/sodium chromoglycate to inhibit mast cell serotonin release induced by compound 48/80. The present study provides the first strong evidence in favour of the hypothesis that dehydroleucodine, xanthatin and 3-benzyloxymethyl-5H-furan-2-one inhibit compound 48/80-induced serotonin release from peritoneal mast cells, acting thus as mast cell stabilizers. Our findings may provide an insight into the design of novel pharmacological agents which may be used to regulate the mast cell response.
Assuntos
Antiulcerosos/farmacologia , Degranulação Celular/efeitos dos fármacos , Lactonas/farmacologia , Mastócitos/efeitos dos fármacos , p-Metoxi-N-metilfenetilamina/farmacologia , Animais , Antiulcerosos/química , Corantes/metabolismo , Relação Dose-Resposta a Droga , Processamento de Imagem Assistida por Computador , Lactonas/química , Masculino , Mastócitos/ultraestrutura , Estrutura Molecular , Peritônio/citologia , Ratos , Ratos Sprague-Dawley , Serotonina/metabolismo , Cloreto de Tolônio/metabolismoRESUMO
Mammalian tissues express both cation-dependent (CD-MPR) and cation-independent (CI-MPR) mannose-6-phosphate receptors, which mediate the targeting of acid hydrolases to lysosomes. The coexistence of the two receptors in all cell types and tissues is still poorly understood. To determine whether these receptors might play a role in maturation, we studied their expression and binding properties in rat liver during perinatal development. CI-MPR expression decreases progressively from 18-day fetuses to adults, whereas the CD-MPR showed a transient decrease in newborn and at the 5th day after birth. Immunostaining of the tissues showed that both receptors localize to hepatocytes at all the ages and, additionally, the CD-MPR was reactive in megakaryocytes at early stages. Binding assays showed differences in the B(max) and K(D) values between the ages studied. These results demonstrate that both receptors change differentially during perinatal development, suggesting that they play distinct roles during organ maturation.
Assuntos
Fígado/embriologia , Fígado/crescimento & desenvolvimento , Receptor IGF Tipo 2/biossíntese , Receptor IGF Tipo 2/química , Animais , Animais Recém-Nascidos , Western Blotting , Divisão Celular , Relação Dose-Resposta a Droga , Regulação da Expressão Gênica no Desenvolvimento , Immunoblotting , Imuno-Histoquímica , Cinética , Lisossomos/metabolismo , Megacariócitos/metabolismo , Ligação Proteica , Ratos , Ratos Sprague-Dawley , Fatores de TempoRESUMO
Adrenal medulla together with the sympathetic nervous system constitute an anatomo functional unit. Both tissues derive from precursor cells which originate from the neural crest and later differentiate during migration into sympathetic neurons or chromaffin cells. Biosynthesis enzymes of catecholamines such as DBH (dopamine beta hydroxylase) and PNMT (phenylethanol amine-N-methyl transferase) as well as the neurotransmitter serotonin , can be detected by immunohistochemical techniques from 15 to 20 prenatal days. Cells migrating along the dorsal aorta could be observed at 15 prenatal days. From day 16 on, three distinct cellular groups could be distinguished according to the intensity of the immunoreactivity: chromaffin, paraganglion and sympathetic ganglion cells. From day 18, chromaffin cells immunostained as DBH' PNMT+ or DBH+ PNMT could be detected differentiating into what would be adrenergic or noradrenergic cells, respectively Progenitor cells migrating from the neural crest to the adrenal cortical blastema reach a micro-environment where glucocorticoids could possibly influence gene expression for PNMT in some of these undifferentiated cells, causing adrenaline synthesis. Serotonin(5HT) immunoreactivity is localized from 17 prenatal days in several groups of the paraganglionic cells where they could be a modulator for chromaffin differentiation.
Assuntos
Animais , Masculino , Feminino , Ratos , Medula Suprarrenal , Células Cromafins , Paragânglios Cromafins/citologia , Medula Suprarrenal , Diferenciação Celular , Linhagem da Célula , Movimento Celular , Dopamina beta-Hidroxilase , Técnicas Imunoenzimáticas , Biomarcadores , Crista Neural , Feniletanolamina N-Metiltransferase , Ratos Wistar , SerotoninaRESUMO
Adrenal medulla together with the sympathetic nervous system constitute an anatomo functional unit. Both tissues derive from precursor cells which originate from the neural crest and later differentiate during migration into sympathetic neurons or chromaffin cells. Biosynthesis enzymes of catecholamines such as DBH (dopamine beta hydroxylase) and PNMT (phenylethanol amine-N-methyl transferase) as well as the neurotransmitter serotonin , can be detected by immunohistochemical techniques from 15 to 20 prenatal days. Cells migrating along the dorsal aorta could be observed at 15 prenatal days. From day 16 on, three distinct cellular groups could be distinguished according to the intensity of the immunoreactivity: chromaffin, paraganglion and sympathetic ganglion cells. From day 18, chromaffin cells immunostained as DBH PNMT+ or DBH+ PNMT could be detected differentiating into what would be adrenergic or noradrenergic cells, respectively Progenitor cells migrating from the neural crest to the adrenal cortical blastema reach a micro-environment where glucocorticoids could possibly influence gene expression for PNMT in some of these undifferentiated cells, causing adrenaline synthesis. Serotonin(5HT) immunoreactivity is localized from 17 prenatal days in several groups of the paraganglionic cells where they could be a modulator for chromaffin differentiation.(AU)