RESUMEN
Horseradish peroxidase (HRP) tracing technique was used to label and localize motor and sensory neurons innervating tibialis anterior, extensor hallucis longus and extensor digitorum longus muscles of the anterior leg compartment of the rat. The tibialis anterior sensory neurons were located in the ipsilateral L4 and L5 spinal ganglia. Cells of origin of tibialis anterior motor endings were also found in the ipsilateral ventral horn of the same cord segments as the labeled sensory ganglia. Extensor hallucis longus sensory neurons were located in L4 to L6 spinal ganglia, while its labeled motor neurons were located in L4 and L5 spinal cord segments. The motor neurons innervating the extensor digitorum longus muscle were located in L4 to L6 spinal cord segments; its sensory neurons were previously localized. All labeled motor and sensory neurons were present on the ipsilateral side. Almost all motoneurons innervating the 3 muscles were present in the dorsolateral nucleus of the ventral horn.
Asunto(s)
Peroxidasa de Rábano Silvestre/metabolismo , Neuronas Motoras , Músculos/inervación , Neuronas Aferentes , Peroxidasas/metabolismo , Ratas/anatomía & histología , Animales , Transporte Biológico Activo , Extremidades , Femenino , Ganglios Espinales/metabolismo , Histocitoquímica , Técnicas para Inmunoenzimas , Masculino , Médula Espinal/metabolismoRESUMEN
The formation of the oesophageal hiatus was studied in 50 human diaphragms in which crura and the median arcuata ligaments were carefully dissected and their fibres were carefully traced to the central tendon. In 98% of the cases the right crus was divided into a medial, a middle and a lateral bundle. In 90% the left crus was divided into a medial and a lateral bundle. The medial bundle of the right crus was a constant component in bounding the hiatus. The undivided crura did not contribute to the borders of the hiatus. 5 variations in the formation of the hiatus were observed. In 62% the hiatus was bounded by the 2 crura mainly the right; the left crus shared only in the formation of the posterior border. In 10% the 2 crura contributed equally to the formation of the hiatus; the hiatus was formed by the medial bands. In 10% the hiatus was formed exclusively by the right crus. In 2% the hiatus was formed exclusively by the left crus. In 16% crura had no direct relation to the hiatus except posteriorly and the hiatus was bounded by a V-shaped band from the median arcuate ligament, this finding has not been previously reported. The functional significance of these variations was discussed.
Asunto(s)
Diafragma/anatomía & histología , Adolescente , Adulto , Niño , Esófago , Femenino , Humanos , Masculino , Persona de Mediana EdadRESUMEN
The distribution of beta-adrenergic receptor sites has been studied in chicken spinal cord and cerebellum using a fluorescent analogue of propranolol, 9-amino-acridin-propranolol (9-AAP). In the cervical and lumbar regions of the spinal cord, beta-adrenoceptor sites were concentrated on cell bodies of alpha-motor neurons of the dorsolateral and ventrolateral nuclear groups of the ventral horn. In the thoracic region, they were present on cell bodies of the preganglionic sympathetic nucleus (dorsal commissural nucleus). In the dorsal horn, the receptor sites were present mainly on cell bodies of columna dorsalis magnocellularis. Sparse distribution of fluorescence was present in other regions of the gray matter. In the cerebellum, a dense distribution of beta-adrenergic receptor sites was observed on Purkinje cell bodies and their apical dendrites. Sparse distribution of receptor sites was present on fine ramifications of Purkinje cell dendrites in the molecular layer. Receptor sites were absent in the granule cell layer and the white matter. These observations indicate that alpha-motor neurons, preganglionic sympathetic neurons, neurons of columna dorsalis magnocellularis, and Purkinje cells are adrenoceptive, while granule cells are non-adrenoceptive.
Asunto(s)
Cerebelo/análisis , Receptores Adrenérgicos beta/análisis , Médula Espinal/análisis , Animales , Pollos , Microscopía Fluorescente , Propranolol/análogos & derivadosRESUMEN
The prenatal development of the human submandibular gland has been investigated in 26 fetuses from the 10th week of gestation to full term. At 10-12 weeks, the glandular elements (primitive ducts and acini) were immature and surrounded by a loose mesenchyme. The acinar cell population increased gradually till the age of 32 weeks, and the rate of increase was diminished thereafter. At 16 weeks, intercalated and striated ducts were distinguished and their number increased till the age of 32 weeks when their number seemed to be stabilized. The development of the granular convoluted tubule cells from the proximal segments of striated ducts occupied the later stages of development. They appeared around the age of 20 weeks and proceeded till full term. At birth, the gland appeared devoid of mucous acini and fat cells and the secretory end-pieces were of the serous type. During the second trimester, periodic acid-Schiff- and alcian blue-positive secretory materials appeared in the epithelial cells of both ducts and acini, and in their lumina. This secretory activity was transitory and disappeared around the age of 28 weeks. The possible function of these secretory products is discussed.
Asunto(s)
Glándula Submandibular/embriología , Citoplasma/ultraestructura , Epitelio/embriología , Epitelio/ultraestructura , Edad Gestacional , Histocitoquímica , Humanos , Glándula Submandibular/metabolismo , Glándula Submandibular/ultraestructuraRESUMEN
Glycogen accumulation in the Clarke's nucleus neuropil of young adult rats whose sciatic nerves were crushed in the first postnatal day was investigated with the electron microscope. Glycogen was observed in synaptic boutons and in small myelinated axons. In some terminals, glycogen accumulated in membrane-bound structures resembling mitochondria and formed large multigranular bodies which were entirely separated from the axoplasm. The multigranular body reached the size of 1.3 micron. Glycogen was present as single beta particles of about 25-40 nm in diameter and in aggregations of large alpha clusters. The astrocytic glycogen distribution was almost similar to that of the control specimens. Glycogen was not observed in other glial cells. It is probable that glycogen accumulation in synaptic terminals of partially deafferentiated Clarke's nucleus may result from impaired glycolysis due to deficient resupply of the distal axon with glycolytic enzymes caused by a defect in axoplasmic transport from the hypoplastic sensory neuronal perikarya.
Asunto(s)
Glucógeno/metabolismo , Médula Espinal/metabolismo , Nervios Espinales/lesiones , Animales , Animales Recién Nacidos , Gránulos Citoplasmáticos/metabolismo , Microscopía Electrónica , Ratas , Ratas Endogámicas , Médula Espinal/ultraestructura , Sinapsis/metabolismoRESUMEN
The sciatic nerve of newborn rats (less than or equal to 16 h old) was crushed with a watchmaker forceps. During the first 4 weeks after the injury, examination of ipsilateral L4 through L6 dorsal root ganglia, their dorsal nerve roots, and the dorsal funiculus revealed the presence of degenerating myelin and axons. Chromatolysis was not observed. In the spinal cord, the degenerating argyrophilia was restricted to the medial part of the dorsal funiculus (fasciculus gracilis). This is interpreted as transganglionic degeneration of the central processes of the pseudounipolar cells. Twelve weeks after nerve crush, there was a noticeable reduction in the size of the leg, foot, and muscles innervated by the sciatic nerve as well as a substantial loss (P less than 0.001) of neurons and myelinated axons in ipsilateral spinal ganglia and their dorsal nerve roots. The reduction was most prominent among the larger sensory neurons (greater than 40 microns) and the larger myelinated axons. A total loss of about 60% of sensory neurons was found in the L4 through L6 spinal ganglia. About 58 and 64% of the myelinated axons were lost in L4 and L5 dorsal roots, respectively. The remaining perikarya and dorsal root axons were hypoplastic.
Asunto(s)
Animales Recién Nacidos/fisiología , Degeneración Nerviosa , Neuronas Aferentes/patología , Nervio Ciático/lesiones , Animales , Femenino , Ganglios Espinales/patología , Masculino , Compresión Nerviosa , Ratas , Ratas Endogámicas , Raíces Nerviosas Espinales/patologíaRESUMEN
Utilizing recent techniques in quantitative stereology, this investigation studied the synaptology of nucleus dorsalis (Clarke's column) in 12-week-old rats whose sciatic nerves were crushed in the 1st postnatal day. Four morphometric variables were analyzed at the levels of L1 and L3 spinal cord segments: total surface area of synaptic contact zones per unit volume (SV), total length of synaptic contact zones per unit area (LA), average length of synaptic membrane (L), and numerical density of synapses per unit volume (NV). The original raw data were corrected for Holmes's effect. The results indicated that peripheral nerve crush at birth induced a transganglionic change in central sensory terminals with a loss of numerous synapses. A significant loss (P less than 0.001) of about 32% in the SV and LA and a significant loss (P less than 0.001) of about 36% in the NV were observed on the experimental side. There was no preferential loss of synapses in either segment. The mean synaptic membrane length showed no significant difference between the control and experimental sides. The control values of the four morphometric variables calculated for L3 were lower than those calculated for L1. The loss of synapses after a peripheral nerve lesion was probably due to the loss of sensory neurons and their central processes, but there were other possibilities.
Asunto(s)
Animales Recién Nacidos/fisiología , Nervio Ciático/lesiones , Médula Espinal/patología , Sinapsis/ultraestructura , Envejecimiento , Animales , Femenino , Región Lumbosacra , Masculino , Compresión Nerviosa , Ratas , Médula Espinal/crecimiento & desarrolloRESUMEN
10 adult rabbits were arranged in five batches, 2 animals of nearly the same body weight in each group. 1 animal in each group was injected with vincristine sulfate whereas the other animal was similarly injected with the dissolving medium and used as a control. The animals were sacrificed 2 days after the last injection, and the areas containing the circumvallate and foliate papillae were examined. Injection of vincristine was followed by a decrease in number and in cell contents of vallate and foliate taste buds. Most of the taste buds which persisted after vincristine injection were full of necrotic debris which represented the remnants of degenerated cells. Possible reasons for degeneration of taste buds after vincristine injections were put forewards.