Synaptic dimorphism in Onychophoran cephalic ganglia

The taxonomic location of the Onychophora has been controversial because of their phenotypic and genotypic characteristics, related to both annelids and arthropods. We analyzed the ultrastructure of the neurons and their synapses in the cephalic ganglion of a poorly known invertebrate, the velvet worm Peripatus sedgwicki, from the mountainous region of El Valle, Mérida, Venezuela. Cephalic ganglia were dissected, fixed and processed for transmission electron microscopy. The animal has a high degree of neurobiological development, as evidenced by the presence of asymmetric (excitatory) and symmetric (inhibitory) synapses, as well as the existence of glial cell processes in a wide neuropile zone. The postsynaptic terminals were seen to contain subsynaptic cisterns formed by membranes of smooth endoplasmic reticulum beneath the postsynaptic density, whereas the presynaptic terminal showed numerous electron transparent synaptic vesicles. From the neurophylogenetic perspectives, the ultrastructural characteristics of the central nervous tissue of the Onychophora show important evolutionary acquirements, such as the presence of both excitatory and inhibitory synapses, indicating functional synaptic transmission, and the appearance of mature glial cells.

Studies on the intrinsic nervous system of the wild rodent Calomys callosus digestive tract. II. The submucous plexus

The submucous plexus of the normal small and large intestine of Calomys callosus was studied by NADH and AChE histochemical techniques and by transmission and scanning electron microscopy. The plexus contains (X + SD) 7,488 + 293 neurons/cm2 in the duodenum, 5,611 + 836 in the jejunum, 2,741 + 360 in the ileum, 3,067 + 179 in the cecum, and 3,817 + 256 in the proximal colon. No ganglia or nerve cell bodies were seen in the esophagus, stomach, distal colon or rectum. The neurons are pear-shaped with a round or oval nucleus and the neuronal cell profile areas were larger in the large intestine than in the small intestine. Most of the neurons display intense AChE activity in the cytoplasm. AChE-positive nerve fibers are present in a primary meshwork of large nerve bundles and in a secondary meshwork of finer nerve bundles. At the ultrastructural level, the ganglia are irregular in shape and covered with fibroblast-like cells. The nucleoplasm of the neurons is finely granular with a few condensations of chromatin attached to the nuclear envelope. In the neuropil numerous varicosities filled with vesicles of different size and electron densities are seen. The pre- and post-synaptic membrane thickenings are asymmetric. Characteristic glial cells with oval nuclei and few organelles are numerous. These data provide a detailed description of this submucosal meshwork.

Características anatómicas macroscópicas y microscópicas del ganglio mesentérico inferior en fetos humanos de término / Macroscopic and microscopic anatomic characteristics of the inferior mesenteric ganglion in human fetuses at term

Se efectúa un estudio de las características anatómicas macroscópicas y microscópicas de los ganglios mesentéricos inferiores en 50 fetos humanos de término de ambos sexos, en los que se practicó la disección bilateral, bajo observación directa con la ayuda de un microscopio de operaciones Carl Zeiss. Se detalla la cantidad de ganglios existenten en cada disección, la individualidad morfológica observada, así como su forma, dimensiones y orientaciones. Se determina su ubicación, relación y conexiones. Se establece su estructura macroscópica, microcópica, vascularización arterial y venosa. Se enfatiza en la importancia de su sistematización como estructura pertenecientes a la parte simpática del sistema nervioso autónomo

Collagen fibers in ganglia of the myenteric plexus

The connective tissue of the myenteric plexus of the human esophagus was studied by light and electron microscope. Collagen fibers were identified by Picrosirius staining with polarisation microscopy and from their fine structural morphology. A capsule of connective tissue invests the ganglia while septa of connective tissue separate groups of ganglion cells, surrounding each ganglion cell and each nerve fiber. Collagen fibrils surround the ganglia each ganglion cell and each nerve fiber. The fibrils are disposed in various orientations forming networks

Fibras elásticas, elaunínicas e oxitalánicas no plexo mientérico do esôfago humano / Elastic fibers, eleaunic and oxitalanic of the human esophagus myenteric plexus

The elastic system in the myenteric plexus of the human esophagus was studied by light and electron microscopy. Elastic, elaunin and oxytalan fibers were identified by their staining characteristic a fine structural morphology. The bulk of the ganglionic sheet consists of coarse eladtic fibers and elaunin fibers. Elaunin fibers and oxytalan fibers form the intraganglionic network. The oxytalan, elaunin and elastic fibers appear to be located in area related to different stresses and deformation to which the ganglia if the myenteric plexus are exposed during the motor activity of the esophageal wall

Aspectos morfológicos e quantitativos do gânglio ciliar no homem / Quantitative and morphological aspects of ciliary ganglion in men

Dez gânglios ciliares humanos, sendo cinco de adultos e cinco de recém-nascidos, foram utilizados para o presente trabalho. Observou-se que ambos os gânglios apresentam na sua constituiçäo neurônios envoltos individualmente por células satélites e imersos em tecido conjuntivo, o que coincide com a estrutura de gânglios ciliares de aves e mamíferos. Os volumes absolutos nuclear, citoplasmático e celular no adulto, säo significativamente maiores que no recém-nacido. Houve uma predominância de fibras colágenas em gânglios de adultos enquanto nos recém-nascidos, a presença de substância intersticial foi significativa

Características anatómicas macroscópicas y microscópicas del ganglio submandibular: (en fetos humanos de término) / Macroscopic and microscopic anatomical characteristics of the submandibular ganglia

Se hace un estudio anatómico detallado de 110 ganglios submandibulares pertenecientes a fetos humanos de término de ambos sexos, teniendo como base la observación directa con la ayuda del Microscopio de Operaciones (Carl Zeiss) de disecciones especializadas, planificadas y ejecutadas al efecto. Se dan detalles referentes a la forma, el color, las dimensiones, la orientación, la estructura microscópica y macroscópica, la vascularización arterial y venosa, la ubicación del ganglio (M.71, 41, D.S.: 4, 32) y se correlaciona con la longitud gonionpogonion de la mandíbula y con el índice parcial de la mandíbula, obteniéndose en ambos casos correlaciones positivas. Se recalca la importancia de los axones preganglionares, postganglionares y de los que sólo atraviesan el ganglio; se esclarece la calidad funcional de dichos axones y se insiste sobre el valor de la sistematización del ganglio