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Lumbar Segments (lumbar + segment)

Distribution by Scientific Domains

Life Sciences	100%

Selected Abstracts

Macroanatomical Investigation of the Aorticorenal Ganglion in 1-Day-Old Infant Sheep

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 3 2009
J. Kle, kowska-Nawrot
Summary The aorticorenal gland belongs to the paired splanchnic ganglion, which is the main component of the coeliac plexus. It lies near the renal artery and suprarenal gland. The research was conducted on 13 1-day-old infant sheep , eight males and five females. Based on the conducted studies, it was concluded that the aorticorenal ganglion is characterized by the variable location in relation to the abdominal aorta, renal artery, caudal vena cava and suprarenal gland (holotopy), the thoracic and lumbar segment of the vertebral column (skeletotopy) (between L1 and L3) and also a different shape (elongated, round, triangular, oval) as well as variable length (the aorticorenal ganglion is longer on the left side of the body; 2.72 mm) and distance from the caudal end of the suprarenal gland (longer on the left side of the body; 8.34 mm). With regard to the sex of the animal, the ganglion is the longest on the left side in ewes (3.02 mm), while in rams it is the longest on the right side (2.68 mm). Regarding the division according to sex, the longest segment was observed on the right side in ewes (9.27 mm), and the shortest segment in rams was also on the right side (6.84 mm). [source]

Nociceptive spinothalamic tract and postsynaptic dorsal column neurons are modulated by paraventricular hypothalamic activation

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 3 2008
Gerardo Rojas-Piloni
Abstract Previously, we demonstrated that stimulation of the paraventricular hypothalamic nucleus diminishes the nociceptive dorsal horn neuronal responses, and this decrease was mediated by oxytocin in the rat. In addition, we have proposed that oxytocin indirectly inhibits sensory transmission in dorsal horn neurons by exciting spinal inhibitory GABAergic interneurons. The main purpose of the present study was to identify which of the neurons projecting to supraspinal structures to transmit somatic information are modulated by the hypothalamic-spinal descending activation. In anaesthetized rats, single-unit extracellular and juxtacellular recordings were made from dorsal horn lumbar segments, which receive afferent input from the toe and hind-paw regions. The projecting spinothalamic tract and postsynaptic dorsal column system were identified antidromically. Additionally, in order to label the projecting dorsal horn neurons, we injected fluorescent retrograde neuronal tracers into the ipsilateral gracilis nucleus and contralateral ventroposterolateral thalamic nucleus. Hence, juxtacellular recordings were made to iontophoretically label the recorded neurons with a fluorescent dye and identify the recorded projecting cells. We found that only nociceptive evoked responses in spinothalamic tract and postsynaptic dorsal column neurons were significantly inhibited (48.1 ± 4.6 and 47.7 ± 8.2%, respectively) and non-nociceptive responses were not affected by paraventricular hypothalamic nucleus stimulation. We conclude that the hypothalamic-spinal system selectively affects the transmission of nociceptive information of projecting spinal cord cells. [source]

Altered sensorimotor development in a transgenic mouse model of amyotrophic lateral sclerosis

EUROPEAN JOURNAL OF NEUROSCIENCE, Issue 10 2004
Julien Amendola
Abstract Most neurodegenerative diseases become manifest at an adult age but abnormalities or pathological symptoms appear earlier. It is important to identify the initial mechanisms underlying such progressive neurodegenerative disease in both humans and animals. Transgenic mice expressing the familial amyotrophic lateral sclerosis (ALS)-linked mutation (G85R) in the enzyme superoxide dismutase 1 (SOD1) develop motor neuron disease at 8,10 months of age. We address the question of whether the mutation has an early impact on spinal motor networks in postnatal mutant mice. Behavioural tests showed a significant delay in righting and hind-paw grasping responses in mutant SOD1G85R mice during the first postnatal week, suggesting a transient motor deficit compared to wild-type mice. In addition, extracellular recordings from spinal ventral roots in an in vitro brainstem,spinal cord preparation demonstrated different pharmacologically induced motor activities between the two strains. Rhythmic motor activity was difficult to evoke with N -methyl- dl -aspartate and serotonin at the lumbar levels in SOD1G85R mice. In contrast to lumbar segments, rhythmic activity was similar in the sacral roots from the two strains. These results strongly support the fact that the G85R mutation may have altered lumbar spinal motor systems much earlier than previously recognized. [source]

Lumbar vertebral morphology and isthmic spondylolysis in a British medieval population

AMERICAN JOURNAL OF PHYSICAL ANTHROPOLOGY, Issue 2 2010
Carol V. Ward
Abstract The British medieval population from Wharram Percy, England, has a greater prevalence of isthmic spondylolysis (11.9% of skeletons, 8.5% at the L5 level) than in modern populations (3%,6%). This may in part be due to differences in activity patterns between groups. However, Ward and Latimer (Spine 30 [2005] 1808,1814) proposed that the likelihood of developing and maintaining spondylolytic defects is also influenced by a lack of sufficient increase in mediolateral separation between articular processes in the lowest lumbar segments, given the human lumbar lordosis. Here, we demonstrate that spondylolytic individuals from Wharram Percy tend to have a less pronounced difference between mediolateral facet joint spacing of adjacent segments in the lowest lumbar region than do unaffected individuals, as seen in modern clinical and skeletal populations. These comparisons suggest that regardless of lifestyle, insufficient mediolateral increase in facet spacing predisposes people to spondylolytic defects, and so interfacet spacing patterns may have predictive utility in a clinical context. We also compare the Wharram Percy sample to a modern sample from the Hamann Todd collection with a typically modern prevalence rate. Data do not support the hypothesis that the Wharram Percy individuals had a less pronounced interfacet increase than the Hamann Todd, although they do have narrower lumbar facet spacing at the lowest three levels. Further investigation of anatomical variation underlying population-specific prevalence rates needs to be conducted. Am J Phys Anthropol 2010. © 2009 Wiley-Liss, Inc. [source]

Canine Spinal Cord Neuron and Axon Myelin Sheath Morphometry

ANATOMIA, HISTOLOGIA, EMBRYOLOGIA, Issue 5 2006
A. C. De Francischini Carvalho
Summary This inedited morphometric study has been developed from healthy canine spinal cord neuron cytoplasm and nucleus, and white matter axonal myelin sheath, from cervical, thoracic and lumbar regions. For the morphometric study, the parameters were area, perimeter, maximum and minimum diameters and roundness for neurons and myelin thickness for axon. For each parameter, 300 neurons were analysed. The results revealed that lumbar neurons had the highest mean values for the analysed parameters, indicating the presence of large neurons in this region, with large axons as a result of myelin thickness, which is proportional to axon calibre. We conclude that these morphometric results can contribute for the establishment of normal patterns, for canine spinal cord cervical, thoracic and lumbar segments. [source]