RESUMO
Glial cell line-derived neurotrophic factor (GDNF) supports and maintains the neuromuscular system during development and through adulthood by promoting neuroplasticity. The aim of this study was to determine if different modes of exercise can promote changes in GDNF expression and neuromuscular junction (NMJ) morphology in slow- and fast-twitch muscles. Rats were randomly assigned to a run training (run group), swim training (swim group), or sedentary control group. GDNF protein content was determined by enzyme-linked immunosorbant assay. GDNF protein content increased significantly in soleus (SOL) following both training protocols (P<0.05). Although not significant, an increase of 60% in the extensor digitorum longus (EDL) followed swim-training (NS; P<0.06). NMJ morphology was analyzed by measuring α-bungarotoxin labeled post-synaptic end plates. GDNF content and total end plate area were positively correlated. End plate area decreased in EDL of the run group and increased in SOL of the swim group. The results indicate that GDNF expression and NMJ morphological changes are activity dependent and that different changes may be observed by varying the exercise intensity in slow- and fast-twitch fibers.
Assuntos
Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Músculo Esquelético/citologia , Junção Neuromuscular/metabolismo , Plasticidade Neuronal/fisiologia , Condicionamento Físico Animal , Análise de Variância , Animais , Ratos , Ratos Sprague-Dawley , Receptores Colinérgicos/metabolismo , Corrida/fisiologia , Natação/psicologiaRESUMO
Neurotrophic factors may play a role in exercise-induced neuroprotective effects, however it is not known if exercise mediates changes in glial cell line-derived neurotrophic factor (GDNF) protein levels in the spinal cord. The aim of the current study was to determine if 2 weeks of exercise alters GDNF protein content in the lumbar spinal cord of young and old rats. GDNF protein was quantified via an enzyme-linked immunosorbent assay and Western blot. Immunohistochemical analysis localized GDNF in choline acetyltransferase (ChAT)-positive motor neurons and cell body areas were measured. Involuntary running in the young animals appeared to elicit the greatest increase in GDNF protein content (sixfold increase), followed by swimming (threefold increase) and voluntary running (twofold increase); however there was no significant difference between the modalities of exercise. Low-intensity running of the old animals significantly increased GDNF protein content in the spinal cord. Both young and old exercised animals showed a doubling in ChAT-positive motor neuron cell body areas. These results suggest that GDNF protein content in the spinal cord is modulated by exercise.
Assuntos
Regulação da Expressão Gênica/fisiologia , Fator Neurotrófico Derivado de Linhagem de Célula Glial/metabolismo , Condicionamento Físico Animal/métodos , Traumatismos da Medula Espinal/patologia , Traumatismos da Medula Espinal/reabilitação , Medula Espinal/metabolismo , Fatores Etários , Análise de Variância , Animais , Autoantígenos/metabolismo , Modelos Animais de Doenças , Locomoção , Masculino , Proteínas de Membrana/metabolismo , Neurônios Motores/metabolismo , Neurônios Motores/patologia , Fatores de Crescimento Neural/metabolismo , Ratos , Ratos Sprague-Dawley , Medula Espinal/patologia , Natação , Fatores de TempoRESUMO
5-Amino-2-phenylpyrimidin-6-ones, some of their desamino derivatives, and miscellaneous derivatives were synthesized and biologically evaluated on both in vitro activity and oral activity in an acute hemorrhagic assay. These compounds contained an alpha-keto-1,3,4-oxadiazole moiety to bind covalently to the Ser-195 hydroxy group of human neutrophil elastase (HNE). Among those tested, compounds 11a-c,e,i-l(F), 11d,e,k(H), 21d,e,k(F), and 21d,e(H) showed a good oral profile. RS-Mixture 3(H) was selected for clinical evaluation based on its oral potency, duration of action, enzyme selectivity, safety profile, and ease of synthesis. Structure-activity relationships (SARs) are discussed.
Assuntos
Inibidores Enzimáticos/síntese química , Elastase de Leucócito/antagonistas & inibidores , Oxidiazóis/síntese química , Administração Oral , Animais , Disponibilidade Biológica , Cricetinae , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Hemorragia/tratamento farmacológico , Humanos , Hidrólise , Pneumopatias/tratamento farmacológico , Oxidiazóis/química , Oxidiazóis/farmacologia , Ratos , Estereoisomerismo , Relação Estrutura-AtividadeAssuntos
Inibidores Enzimáticos/síntese química , Elastase de Leucócito/antagonistas & inibidores , Oxidiazóis/síntese química , Pirimidinonas/síntese química , Administração Oral , Animais , Cristalografia por Raios X , Cães , Desenho de Fármacos , Inibidores Enzimáticos/química , Inibidores Enzimáticos/farmacologia , Haplorrinos , Humanos , Oxidiazóis/química , Oxidiazóis/farmacologia , Pirimidinonas/química , Pirimidinonas/farmacologia , Ratos , Relação Estrutura-AtividadeRESUMO
A series of alpha-ketooxadiazole compounds was prepared and evaluated in vitro as potential inhibitors of human neutrophil elastase (HNE), proteinase-3 (PR-3), and porcine pancreatic elastase (PPE). Several compounds have been found to be very potent, fast, reversible, and selective inhibitors of HNE with Ki values below 100 pM. The highest kon value exceeded 10(7) M(-1) s(-1). Some alpha-ketooxadiazoles were also very effective against PR-3 and PPE with Ki values in the range of 5(-10) nM and 0.1(-2) nM, respectively. The two rings, 1,2,4- and 1,3,4-oxadiazole, are amenable to substitutions, extending the P' side of the inhibitor and allowing additional binding interactions at S' subsites of the enzyme. Nonpeptidic HNE inhibitors containing the oxadiazole heterocycle displayed promising oral bioavailability.
Assuntos
Endopeptidases , Elastase de Leucócito/antagonistas & inibidores , Oxidiazóis/química , Oxidiazóis/farmacocinética , Catepsina G , Catepsina L , Catepsinas/metabolismo , Quimotripsina/metabolismo , Cisteína Endopeptidases , Humanos , Cinética , Oxidiazóis/síntese química , Pâncreas/enzimologia , Serina EndopeptidasesRESUMO
The determination of the relationship between ligand affinity and bioactivity is important for the understanding of receptor function in biological systems and for drug development. Several physiological and pathophysiological functions of bradykinin (BK) are mediated via the B2 receptor. In this study, we have examined the relationship between B2 receptor (soluble and membrane-bound) binding of BK peptidic antagonists, inhibition of calcium signalling at a cellular level, and in vitro inhibition of ileum contraction. Only human systems were employed in the experiments. Good correlations between the studied activities of BK antagonists were observed for a variety of different peptidic structures. The correlation coefficients (r) were in the range of 0.905 to 0.955. In addition, we analyzed the effect of the C-terminal Arg9 removal from BK and its analogs on B2 receptor binding. The ratios of binding constants (Ki(+Arg)/Ki(-Arg)) for the Arg9 containing compounds and the corresponding des-Arg9 analogs varied from about 10 to 250,000. These ratios strongly depend on the chemical structures of the compounds. The highest ratios were observed for two natural agonist pairs, BK/des-Arg9-BK and Lys0-BK/des-Arg9-Lys0-BK.