RESUMEN
Background electroacupuncture (EA) at acupoint ST-36 (Zusanli) has been used to alleviate gastrointestinal symptoms and improve gastrointestinal motility, but the effects and mechanisms of EA on enteric nervous system (ENS) have scarcely been investigated. SD rats were randomly divided into eight groups: normal control group, diabetes mellitus group (DM), chronic high-frequency EA (C-HEA), chronic low-frequency EA (C-LEA), chronic sham stimulation group (C-SEA), acute high-frequency EA group (A-HEA), acute low-frequency EA group (A-LEA), and diabetic with acute sham stimulation group (A-SEA). The parameters of HEA included a frequency of 100 Hz and an amplitude of 1 mA, while the parameters for LEA were 10 Hz and 1 mA. The expressions of PGP9.5, neuronal nitric oxide synthase neurons, CHAT neurons, glia cell line-derived neurotrophic factor (GDNF) and p-Akt were measured by immunofluorescence or immunohistochemistry, real-time PCR, and Western blotting methods in colon tissues of each rat. The total neurons and the two types of enteric neurons (neuronal nitric oxide synthase and choline acetyl transferase neurons), together with GDNF and p-Akt in the mRNA and protein level were significantly decreased in DM group compared with the normal control group in colon (P < 0.01). Compared with DM or all other DM with EA groups, the chronic HEA could induce a more significant quantitative increase in the mRNA and protein level of the enteric neurons and GDNF and p-Akt in colon (P < 0.01). EA with high-frequency and long-term stimuli at acupoint ST-36 can induce regeneration of lost enteric neurons in diabetic rats, and GDNF and PI3K/Akt signal pathway may play an important role in EA-induced regeneration of impaired enteric neurons.
Asunto(s)
Puntos de Acupuntura , Colon/inervación , Diabetes Mellitus Experimental/terapia , Electroacupuntura/métodos , Sistema Nervioso Entérico/enzimología , Factor Neurotrófico Derivado de la Línea Celular Glial/metabolismo , Regeneración Nerviosa , Fosfatidilinositol 3-Quinasa/metabolismo , Proteínas Proto-Oncogénicas c-akt/metabolismo , Transducción de Señal , Animales , Colina O-Acetiltransferasa/metabolismo , Diabetes Mellitus Experimental/enzimología , Diabetes Mellitus Experimental/genética , Diabetes Mellitus Experimental/fisiopatología , Sistema Nervioso Entérico/fisiopatología , Factor Neurotrófico Derivado de la Línea Celular Glial/genética , Masculino , Óxido Nítrico Sintasa de Tipo I/genética , Óxido Nítrico Sintasa de Tipo I/metabolismo , Fosforilación , Proteínas Proto-Oncogénicas c-akt/genética , ARN Mensajero/metabolismo , Ratas Sprague-Dawley , Ubiquitina Tiolesterasa/genética , Ubiquitina Tiolesterasa/metabolismoRESUMEN
Colostrum is an indispensable source of antibodies (IgG) protecting the newborn pig against infection. We studied the effect of feeding colostrum and purified IgG on early structure and development of the gastrointestinal tract (GIT). Newborn littermate pigs were fed either colostrum, an elemental diet (ED), or an ED supplemented with purified serum IgG (ED + IgG) for 24 h or then only ED up to 72 h. Afterwards, pigs were slaughtered. Colostrum-fed pigs or ED supplemented with IgG (ED + IgG) increased thickness (P < 0.001) of stomach mucosa and muscularis (P < 0.05) compared to the ED group not receiving IgG. Feeding an ED supplemented with IgG improved morphology of the GIT towards that of colostrum-fed piglets and indicates a beneficial effect of IgG on GIT development in neonatal pigs. Immunohistochemical studies indicate that ED feeding may influence the expression of nitric oxide synthase in jejunal myenteric (but not submucous) neurons of newborn pigs.
Asunto(s)
Alimentación Animal/análisis , Calostro , Dieta/veterinaria , Tracto Gastrointestinal/anatomía & histología , Inmunoglobulina G/farmacología , Porcinos , Fenómenos Fisiológicos Nutricionales de los Animales , Animales , Sistema Nervioso Entérico/efectos de los fármacos , Sistema Nervioso Entérico/enzimología , Sistema Nervioso Entérico/fisiología , Regulación Enzimológica de la Expresión Génica/efectos de los fármacos , Óxido Nítrico Sintasa/genética , Óxido Nítrico Sintasa/metabolismoRESUMEN
The aim of the present work is to investigate a putative junction transmission [nitric oxide (NO) and ATP] in the human colon and to characterize the electrophysiological and mechanical responses that might explain different functions from both neurotransmitters. Muscle bath and microelectrode techniques were performed on human colonic circular muscle strips. The NO donor sodium nitroprusside (10 microM), but not the P2Y receptor agonist adenosine 5'-O-2-thiodiphosphate (10 microM), was able to cause a sustained relaxation. NG-nitro-L-arginine (L-NNA) (1 mM), a NO synthase inhibitor, but not 2'-deoxy-N6-methyl adenosine 3',5'-diphosphate tetraammonium salt (MRS 2179) (10 microM), a P2Y antagonist, increased spontaneous motility. Electrical field stimulation (EFS) at 1 Hz caused fast inhibitory junction potentials (fIJPs) and a relaxation sensitive to MRS 2179 (10 microM). EFS at higher frequencies (5 Hz) showed biphasic IJP with fast hyperpolarization sensitive to MRS 2179 followed by sustained hyperpolarization sensitive to L-NNA; both drugs were needed to fully block the EFS relaxation at 2 and 5 Hz. Two consecutive single pulses induced MRS 2179-sensitive fIJPs that showed a rundown. The rundown mechanism was not dependent on the degree of hyperpolarization and was present after incubation with L-NNA (1 mM), hexamethonium (100 microM), MRS 2179 (1 microM), and NF023 (10 microM). We concluded that single pulses elicit ATP release from enteric motor neurons that cause a fIJP and a transient relaxation that is difficult to maintain over time; also, NO is released at higher frequencies causing a sustained hyperpolarization and relaxation. These differences might be responsible for complementary mechanisms of relaxation being phasic (ATP) and tonic (NO).
Asunto(s)
Adenosina Trifosfato/metabolismo , Colon Sigmoide/inervación , Sistema Nervioso Entérico/metabolismo , Motilidad Gastrointestinal , Relajación Muscular , Músculo Liso/inervación , Neuronas Nitrérgicas/metabolismo , Óxido Nítrico/metabolismo , Potenciales de Acción , Anciano , Anciano de 80 o más Años , Colon Sigmoide/efectos de los fármacos , Estimulación Eléctrica , Sistema Nervioso Entérico/efectos de los fármacos , Sistema Nervioso Entérico/enzimología , Inhibidores Enzimáticos/farmacología , Motilidad Gastrointestinal/efectos de los fármacos , Humanos , Persona de Mediana Edad , Relajación Muscular/efectos de los fármacos , Músculo Liso/efectos de los fármacos , Inhibición Neural , Unión Neuromuscular/metabolismo , Antagonistas Nicotínicos/farmacología , Neuronas Nitrérgicas/efectos de los fármacos , Neuronas Nitrérgicas/enzimología , Donantes de Óxido Nítrico/farmacología , Óxido Nítrico Sintasa/antagonistas & inhibidores , Óxido Nítrico Sintasa/metabolismo , Receptores Purinérgicos P2/efectos de los fármacos , Receptores Purinérgicos P2/metabolismo , Factores de TiempoRESUMEN
Nitric oxide synthase catalyzes the production of nitric oxide, a multifunctional signaling molecule that affects diverse aspects of animal physiology such as cell proliferation, differentiation, neurotransmission and apoptosis. Here, we report the cloning and expression pattern of the zebrafish nnos. This gene was mapped to zebrafish linkage group 5. The spatial and temporal expression pattern of nnos in embryonic zebrafish was analyzed by whole mount in situ hybridization. nnos is widely expressed in the embryonic nervous system. Expression of zebrafish nnos appeared at 16 hours post-fertilization in the hypothalamus and by 3 days post-fertilization was present in discrete locations in the central nervous system as well as the enteric nervous system. Some nnos-positive cells were mapped to specific locations in the central nervous system using tyrosine hydroxylase as a specific marker indicating that nnos transcripts were present in the olfactory bulb, anterior diencephalon, posterior hypothalamus and anterior hindbrain.