RESUMO
The neurotransmitter 5-HT regulates early developmental processes in the CNS. In the present study we followed the embryonic and postnatal development of serotonergic raphe neurons and catecholaminergic target systems in the brain of 5-HT1A receptor knockout (KO) and overexpressing (OE) in comparison with wild-type (WT) mice from embryonic day (E) 12.5 to postnatal day (P) 15.5. Up to P15.5 no differences were apparent in the differentiation and distribution of serotonergic neurons in the raphe area as revealed by the equal number of serotonergic neurons in the dorsal raphe in all three genotypes. However, the establishment of serotonergic projections to the mesencephalic tegmentum and hypothalamus was delayed at E12.5 in KO and OE animals and projections to the cerebral cortex between E16.5 and E18.5 were delayed in OE mice. This delay was only transient and did not occur in other brain areas including septum, hippocampus and striatum. Moreover, OE mice caught up with WT and KO animals postnatally such that at P1.5 serotonergic innervation of the cortex was more extensive in the OE than in KO and WT mice. Tissue levels of 5-HT and of its main metabolite 5-hydroxyindoleacetic acid as well as 5-HT turnover were considerably higher in brains of OE mice and slightly elevated in KO mice in comparison with the WT, starting at E16.5 through P15.5. The initial differentiation of dopaminergic neurons and fibers in the substantia nigra at E12.5 was transiently delayed in KO and OE mice as compared with WT mice, but no abnormalities in noradrenergic development were apparent in later stages. The present data indicate that 5-HT1A receptor deficiency or overexpression is associated with increased 5-HT synthesis and turnover in the early postnatal period. However, they also show that effects of 5-HT1A KO or OE on the structural development of the serotonergic system are at best subtle and transient. They may nonetheless contribute to the establishment of increased or reduced anxiety-like behavior, respectively, in adult mice.
Assuntos
Núcleos da Rafe/crescimento & desenvolvimento , Receptor 5-HT1A de Serotonina/genética , Receptor 5-HT1A de Serotonina/fisiologia , Serotonina/fisiologia , Animais , Autorradiografia , Monoaminas Biogênicas/metabolismo , Western Blotting , Catecolaminas/fisiologia , Hipocampo/metabolismo , Ácido Hidroxi-Indolacético/metabolismo , Imuno-Histoquímica , Camundongos , Camundongos Knockout , Mutação/fisiologia , Neostriado/metabolismo , Núcleos da Rafe/embriologia , Reação em Cadeia da Polimerase Via Transcriptase Reversa , Proteínas S100/metabolismoRESUMO
Previously, we showed that mice that overexpress the 5-HT(1A) receptor transiently from embryonic to perinatal stages show reduced anxiety and changes in brain serotonin turnover as adults. Here, we investigated the long-term effects of the temporary overexpression of the 5-HT(1A) receptor during early embryonic and perinatal development on the performance in two memory tasks. In the hole-board test mice that were homozygous for the transgene showed similar behavioral habituation but increased locomotion compared to heterozygous mice. In contrast water-maze performance of homozygous mice was impaired compared to heterozygous mice. These results suggest that a transient overexpression of 5-HT(1A) receptor during embryonic and perinatal development has detrimental effects on water-maze performance at adult stages.
Assuntos
Comportamento Exploratório/fisiologia , Habituação Psicofisiológica/fisiologia , Aprendizagem em Labirinto/fisiologia , Memória/fisiologia , Receptor 5-HT1A de Serotonina/fisiologia , Análise de Variância , Animais , Feminino , Regulação da Expressão Gênica no Desenvolvimento , Hipocampo/crescimento & desenvolvimento , Hipocampo/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Receptor 5-HT1A de Serotonina/genética , Fatores SexuaisRESUMO
The pulmonary endothelin (ET) system has been implicated in the pathogenesis of chronic lung diseases such as pulmonary hypertension, asthma, chronic obstructive lung disease, idiopathic pulmonary fibrosis, and bronchiolitis obliterans. However, the etiologic role of ET-1 in these diseases has not yet been established. We recently demonstrated that ET-1 transgenic mice, generated using the human prepro-ET-1 expression cassette including the cis-acting transcriptional regulatory elements, had predominant transgene expression in lung, brain, and kidney. We used these mice in the present study to analyze the pathophysiologic consequences of long-term pulmonary overexpression of ET-1. We found that ET-1 overexpression in the lungs did not result in significant pulmonary hypertension, but did result in development of a progressive pulmonary fibrosis and recruitment of inflammatory cells (predominantly CD4-positive cells). Our study provides evidence that a long-term activated pulmonary ET system, without any other stimuli, produces chronic lymphocytic inflammation and lung fibrosis. This suggests that overexpression of ET-1 may be a central event in the pathogenesis of lung diseases associated with fibrosis and chronic inflammation, such as pulmonary fibrosis and bronchiolitis.
Assuntos
Endotelina-1/metabolismo , Pulmão/patologia , Fibrose Pulmonar/patologia , Animais , Apoptose , Gasometria , Brônquios/irrigação sanguínea , Brônquios/crescimento & desenvolvimento , Brônquios/metabolismo , Brônquios/patologia , Linfócitos T CD4-Positivos/imunologia , Divisão Celular , Doença Crônica , Endotelina-1/genética , Humanos , Hipertensão Pulmonar/genética , Hipertensão Pulmonar/metabolismo , Imuno-Histoquímica , Inflamação/genética , Inflamação/imunologia , Inflamação/metabolismo , Inflamação/patologia , Pulmão/irrigação sanguínea , Pulmão/imunologia , Pulmão/metabolismo , Masculino , Camundongos , Camundongos Transgênicos , Neovascularização Fisiológica , Tamanho do Órgão , Especificidade de Órgãos , Artéria Pulmonar/crescimento & desenvolvimento , Fibrose Pulmonar/genética , Fibrose Pulmonar/imunologia , Fibrose Pulmonar/metabolismo , Receptores de Endotelina/genética , Receptores de Endotelina/metabolismo , Transgenes/genética , Pressão VentricularRESUMO
The filamentous fungus Penicillium olsonii secretes several polygalacturonases (PGs) with molecular masses of about 47 kDa. These enzymes consist of several basic and acidic isoforms, with dominant activities at pI 4.5 and pI 7.9. Two polygalacturonase genes, pg1 and pg2, have been cloned. The corresponding enzymes, PG1 and PG2, consist of 370 and 380 amino acids, respectively, and show significant similarities to endo-polygalacturonases from other filamentous fungi. Targeted disruption of pg1 resulted in the elimination of all basic PG isoforms. In contrast, disruption of pg2 reduced, but did not eliminate the acidic PG activities. The PGs of P. olsonii must therefore be encoded by a gene family of at least three genes. Induction studies with various carbon sources revealed that the acidic and basic isoforms are differentially regulated. Pectin is the best inducer of the acidic PG isoforms. The basic isoforms, however, are best induced by monosaccharides like glucose, alpha-L-rhamnose and alpha-L-arabinose.