RESUMEN
It is accepted that the tone of the parasympathetic nervous system increases after VMH lesion, whereas the sympathetic tone decreases. To reinforce investigations over outcomes from disturbances of the hypothalamic neuronal systems on peripheral autonomic nerve activity this study determined the acetylcholinesterase (AchE) activity in visceral organs, known as vagal targets, from VMH-lesioned obese rats. It was found that AchE activity was significantly increased in liver, pancreas, and stomach from these animals. However, it was not changed in kidneys, being decreased in spleen. The results suggest that AchE activity is enhanced in vagus innervated tissues to following up the unbalance of the autonomic nervous system as observed in VMH lesion-induced obesity.
Asunto(s)
Acetilcolinesterasa/metabolismo , Regulación del Apetito/fisiología , Obesidad/fisiopatología , Nervio Vago/metabolismo , Núcleo Hipotalámico Ventromedial/fisiopatología , Vísceras/inervación , Acetilcolina/metabolismo , Tejido Adiposo/fisiología , Animales , Sistema Nervioso Autónomo/metabolismo , Sistema Nervioso Autónomo/fisiopatología , Sistema Digestivo/inervación , Sistema Digestivo/metabolismo , Sistema Digestivo/fisiopatología , Modelos Animales de Enfermedad , Hiperfagia/fisiopatología , Masculino , Obesidad/etiología , Ratas , Ratas Wistar , Regulación hacia Arriba/fisiología , Nervio Vago/anatomía & histología , Núcleo Hipotalámico Ventromedial/lesiones , Vísceras/metabolismo , Vísceras/fisiopatologíaRESUMEN
Struthio camelus domesticus (Swart, 1987) es descrita como reflejo del híbrido natural de avestruces de granja en Sudáfrica, la que actualmente se conoce como avestruz de cuello negro o African Black. Esta ave fue desarrollada mediante programas de mejoramiento genético, con el objetivo de aumentar el valor comercial de la especie. Se caracteriza por ser de menor talla y más fértil que las otras subespecies, estructura del plumaje bien desarrollada, carácter dócil, y de fácil crianza en granjas, ya que es tremendamente curiosa y amigable con los humanos (Deeming, 2001; Camiruaga, 2004). En relación a las características anatómicas generales del tracto digestivo, Camiruaga & Simonetti, (2003) señalan que el avestruz presenta semejanzas y diferencias, tanto con otras aves, como con los rumiantes y otros herbívoros (equinos). Del análisis comparativo con la gallina, presenta ciertas diferencias anatómicas, una de ellas es no presentar buche, órgano almacenador de alimento que existe en otras aves. El proventrículo y el estómago muscular (molleja), en el avestruz, pueden cumplir dicha función (Angel, 1996). No presentan vesícula biliar, por lo que el vaciamiento de la bilis se realiza directamente al intestino delgado. Además, el intestino grueso del avestruz, a diferencia de otras especies, representa el 50 % del largo total del tubo digestivo y el intestino delgado corresponde sólo al 35,5%. (Camiruaga, 2004). En el presente trabajo se analizó la histología normal de los diferentes segmentos del tubo digestivo del avestruz: esófago, proventrículo, estómago muscular (molleja o ventrículo), intestino delgado (duodeno, yeyuno e íleon) e intestino grueso (ciego, colon y recto), y se analizó comparativamente con especies a las que se le asocia morfológicamente, como las aves domésticas, rumiantes, seudo rumiantes (camélidos) y algunos otros herbívoros.
Asunto(s)
Animales , Reiformes/anatomía & histología , Sistema Digestivo/anatomía & histología , Sistema Digestivo/crecimiento & desarrollo , Sistema Digestivo/inervación , Sistema Digestivo/irrigación sanguínea , Anatomía VeterinariaRESUMEN
An important challenge for both students and teachers of physiology is to integrate the different areas in which physiological knowledge is didactically divided. In developing countries, such an issue is even more demanding, because budget restrictions often affect the physiology program with laboratory classes being the first on the list when it comes to cuts in expenses. With the aim of addressing this kind of problem, the graduate students of our department organized a physiology summer course offered to undergraduate students. The objective was to present the different physiological systems in an integrated fashion. The strategy pursued was to plan laboratory classes whose experimental results were the basis for the relevant theoretical discussions. The subject we developed to illustrate physiology integration was the study of factors influencing salivary secretion.
Asunto(s)
Educación de Postgrado en Medicina , Fisiología/educación , Enseñanza , Amilasas/metabolismo , Brasil , Ritmo Circadiano , Países en Desarrollo , Sistema Digestivo/inervación , Ejercicio Físico/fisiología , Humanos , Laboratorios , Masticación/fisiología , Fenómenos Fisiológicos del Sistema Nervioso , Investigación , Saliva/metabolismoAsunto(s)
Humanos , Gastropatías/enfermería , Enfermedades de la Boca/enfermería , Enfermedades del Esófago/enfermería , Enfermedades Nasales/enfermería , Enfermedades Intestinales/enfermería , Hepatopatías/enfermería , Sistema Digestivo/inervación , Sistema Digestivo/irrigación sanguínea , Digestión , Atención Dirigida al PacienteRESUMEN
Evidence for the presence and potential co-existence of vasoactive intestinal polypeptide (VIP), pituitary adenylate cyclase-activating polypeptide (PACAP) and nitric oxide synthase (NOS) in gastro-intestinal endocrine cells and/or nerve fibers is conflicting and very few results exist on development. This immunofluorescence study aims to clarify the appearance and localization of VIP, PACAP and NOS in the gastro-intestinal tract of the Axolotl, Ambystoma mexicanum, during ontogeny. VIP-immunoreactivity appeared in nerve fibers as early as on day 3 after hatching likely indicating a particular role, such as a trophic action, of VIP in very early development. PACAP-immunoreactivity was observed 3 days later within the VIP-immunoreactive (-IR) fibers. From this time on, VIP- and PACAP-immunoreactivity exhibited complete co-existence. VIP/PACAP-IR fibers were found throughout the gastro-intestinal tract. They were most prominent in the myenteric plexus and the muscle layers and less frequent in the submucosa. NOS-immunoreactivity appeared as late as at the 1st (64 days) juvenile stage in a subpopulation of the VIP/PACAP-IR fibers that contacted submucosal arteries. We found only very few VIP/PACAP-IR perikarya, indicating that part of the VIP/PACAP-IR fibers is of extrinsic origin. On day 12 and in the 1st and 2nd (104 days) juvenile stage, infrequent PACAP-IR entero-endocrine cells were noted, while neither VIP- nor NOS-immunoreactivity occurred in endocrine cells at any stage of development. The complete coexistence of neuronal PACAP- and VIP-immunoreactivities and their very early appearance in ontogeny may suggest important and coordinated roles of both peptides in the control of Axolotl gastro-intestinal activity, while the VIP/ PACAP/NOS-IR fibers may be involved in the regulation of submucosal blood flow.
Asunto(s)
Ambystoma mexicanum/crecimiento & desarrollo , Sistema Digestivo/crecimiento & desarrollo , Neuropéptidos/metabolismo , Óxido Nítrico Sintasa/metabolismo , Péptido Intestinal Vasoactivo/metabolismo , Animales , Sistema Digestivo/inervación , Sistema Digestivo/metabolismo , Células Enteroendocrinas/citología , Células Enteroendocrinas/metabolismo , Técnica del Anticuerpo Fluorescente Indirecta , Inmunohistoquímica , Larva/crecimiento & desarrollo , Larva/metabolismo , Plexo Mientérico/citología , Plexo Mientérico/crecimiento & desarrollo , Plexo Mientérico/metabolismo , Óxido Nítrico Sintasa de Tipo I , Polipéptido Hipofisario Activador de la Adenilato-CiclasaRESUMEN
Spinal cord transection (SCT) delays gastric emptying (GE), and intestinal and gastrointestinal (GI) transit of liquid in awake rats. This study evaluates the neural mechanisms involved in this phenomenon. Male Wistar rats (N = 147) were fasted for 16 h and had the left jugular vein cannulated followed by laminectomy or laminectomy + complete SCT between T4 and T5 vertebrae. The next day, a test meal (1.5 ml of a phenol red solution, 0.5 mg/ml in 5% glucose) was administered by gavage feeding and 10 min later cervical dislocation was performed. Dye recovery in the stomach, and proximal, mid and distal small intestine was determined by spectrophotometry. SCT inhibited GE and GI transit since it increased gastric recovery by 71.3% and decreased mid small intestine recovery by 100% (P < 0.05). Subdiaphragmatic vagotomy, celiac ganglionectomy + section of the splanchnic nerves, i.v. hexamethonium (20 mg/kg) or yohimbine (3 mg/kg) prevented the development of the SCT effect on GE and GI transit. Pretreatment with i.v. naloxone (2 mg/kg), L-NAME (3 mg/kg) or propranolol (2 mg/kg) was ineffective. Bilateral adrenalectomy or guanethidine (10 mg/kg) increased the magnitude of the GE inhibition, while i.v. prazosin (1 mg/kg) or atropine (0.5 mg/kg) decreased the magnitude but did not abolish the GE inhibition. In summary, the inhibition of GI motility observed 1 day after thoracic SCT in awake rats seems to involve vagal and possibly splanchnic pathways.
Asunto(s)
Sistema Nervioso Autónomo/fisiopatología , Fenómenos Fisiológicos del Sistema Digestivo , Sistema Digestivo/inervación , Vaciamiento Gástrico/fisiología , Enfermedades Gastrointestinales/etiología , Enfermedades Gastrointestinales/fisiopatología , Motilidad Gastrointestinal/fisiología , Traumatismos de la Médula Espinal/complicaciones , Médula Espinal/fisiopatología , Animales , Sistema Nervioso Autónomo/efectos de los fármacos , Sistema Nervioso Autónomo/patología , Fenómenos Fisiológicos Cardiovasculares/efectos de los fármacos , Sistema Digestivo/efectos de los fármacos , Ganglios Simpáticos/fisiología , Ganglios Simpáticos/cirugía , Ganglionectomía/efectos adversos , Vaciamiento Gástrico/efectos de los fármacos , Enfermedades Gastrointestinales/tratamiento farmacológico , Motilidad Gastrointestinal/efectos de los fármacos , Indicadores y Reactivos/farmacocinética , Masculino , Fenolsulfonftaleína/farmacocinética , Ratas , Ratas Wistar , Médula Espinal/patología , Nervios Esplácnicos/fisiología , Nervios Esplácnicos/cirugía , Simpatectomía/efectos adversos , Vértebras Torácicas , Factores de Tiempo , Vagotomía/efectos adversosRESUMEN
We have examined the sizes of nerve cells present in the myenteric plexus in the human esophagus, stomach, duodenum and sigmoid colon using a nonhistochemical method (Giemsa) in laminar preparations of the muscularis externa. The collagen and elastic system related fibers in the myenteric ganglia were also qualitatively evaluated. The major mean of perikaryal area was observed in the esophagus (489.97 micron 2 +/- 212.35 micron 2) and the minor in the sigmoid colon (241.64 micron 2 +/- 122.62 micron 2). There were no significant differences between the mean areas of the myenteric neurons in the stomach (284.77 micron 2 +/- 134.70 micron 2) and in the duodenum (291.39 micron 2 +/- 157.86 micron 2). In all regions a ganglionic capsule of collagen fibers with thin septa surrounding isolated or grouped neurons was observed. The elastic and elastic-related fibers (elaunin and oxytalan fibers) were also present in both the ganglionic capsule and inside the ganglia. There were no differences among the regions. These data suggest that factors such as size of nerve cells and structural aspects of the ganglionic capsule are not related with the incidence of megaesophagus and megacolon.
Asunto(s)
Sistema Digestivo/inervación , Plexo Mientérico/citología , Neuronas/citología , Adulto , Análisis de Varianza , Colorantes Azulados , Cadáver , Tamaño de la Célula , Colágeno , Tejido Elástico/citología , Femenino , Humanos , MasculinoRESUMEN
Se revisan las bases anatómicas, bioquímicas y neurofisiológicas del aparato digestivo. Asimismo, se analiza la farmacología de las principales drogas con acción procinética a nivel del tracto gastrointestinal, sus indicaciones, efectos secundarios y dosis en pediatría.
Asunto(s)
Humanos , Lactante , Preescolar , Niño , Compuestos de Betanecol , Compuestos de Betanecol/administración & dosificación , Compuestos de Betanecol/análisis , Sistema Digestivo/anatomía & histología , Sistema Digestivo/inervación , Domperidona , Domperidona/administración & dosificación , Domperidona/análisis , Motilidad Gastrointestinal/efectos de los fármacos , Metoclopramida , Metoclopramida/administración & dosificación , Metoclopramida/análisis , Farmacocinética , Intestinos/fisiologíaRESUMEN
The enteric nervous system (ENS) is an important neural network that integrates, modulates and coordinates various motor functions of the digestive tract. Chagas' disease, to a variable extent and in a nonsystematic way, causes destruction of ENS neurons throughout the digestive tract. The studies carried out on the pathophysiology of the digestive form of this disease have provided, as a corollary, a better understanding of the participation of the ENS in the regulation of the normal motor activities of the digestive tract and have led to the conclusion that the disease is a true model of intrinsic denervation of the human digestive tract. Among the motor alterations caused by impairment of the digestive tract in Chagas' disease are: absence of peristalsis in the esophagus, achalasia of the cardia, loss of the accommodation reflex in the proximal stomach, gastric emptying disorders, changes in the migrating motor complex (MMC), disappearance of postprandial motor phenomena in the colon and rectum, lack of relaxation of the internal sphincter of the anus, and anomalous responses of the gall bladder to cholekinetic stimuli.