Number Of Neuronal Somata Research Articles

0067 An Anatomic Substrate for GABAergic Processes to Suppress Active Sleep and Promote Wakefulness in the Nucleus Pontis Oralis

Abstract Introduction Our previous electrophysiologic data have provided compelling evidence that GABAergic processes in the nucleus pontis oralis (NPO) play a critical role in the generation and maintenance of wakefulness as well as active (REM) sleep (AS). We therefore hypothesized that one of the neuronal mechanisms of GABA actions in the NPO to promote wakefulness and suppress AS is due to a direct GABAergic inhibition of NPO neurons that generate AS (AS-generator neurons). However, the anatomical substrate for this inhibition is undetermined. Accordingly, the present study was undertaken to examine whether there is any direct interaction between GABAergic neurons and glutamatergic AS-generator neurons in the NPO. Methods Adult cats were deeply anesthetized and perfused transcardially. The brainstem containing the NPO was removed, postfixed and cut into 15 μm coronal sections with a Reichert-Jung cryostat. The sections were incubated with a mixture of a rabbit polyclonal antibodies against glutamine and GABA following the procedure of double fluorescence immunohistochemistry. Results There was a large number of neuronal somata labeled by anti-glutamine antibody and terminals labeled by anti-GABA antibody in the NPO. These glutamine-positive neurons were medium to large, multipolar cells (> 20 μm), which resemble glutamatergic, AS-generator neurons that have been previously identified in the NPO. Specifically, majority of glutamatergic neuronal somata were closely apposed by multiple GABAergic terminals, indicating that AS-generator neurons in the NPO receive direct GABAergic inputs. Conclusion The present results demonstrate that a direct connection exists between glutamatergic AS-generator neurons and GABAergic processes in the NPO. These data provide the anatomical evidence which supports our hypothesis that the pontine GABAergic control of wakefulness and active sleep is partially mediated via GABAergic processes project to NPO AS-generator neurons that suppress the activity of these cells. Support NS092383

Sexual Dimorphism in Shape and Distribution of GABA-Like Immuno-Reactive Neurons in Cricket Terminal Abdominal Ganglion

We studied age-related sexual dimorphism of the terminal abdominal ganglion in the cricket, Gryllus bimaculatus using osmium/ethyl-gallate staining and GABA immunohistochemistry. We determinedthat the volume of the terminal abdominal ganglion increases with increasing body size. The growth ratio between longitude and width in the terminal abdominal ganglion is the same in all nymph stages and sexes. However, the longitudinal growth of the male terminal abdominal ganglion ceases in the 8th instar and the adult stage. Therefore, in the adult stage, sexual dimorphism is observed in ganglion morphology. Additionally, sexual dimorphism is also observed in numbers of neuronal somata and GABA-like immunoreactive neurons in the terminal abdominal ganglion. At the beginning of the 8th instar, the number of somata is greater in female crickets than in males. GABA-like immunoreactive neurons, which were classified into eight clusters, increased between the 8th instar and adult in both sexes, but their numbers were sexually dimorphic in the 7th and 8th instars, and in the adult. Females had a greater number of GABA-like immunoreactive neurons than males. These differences occurred mainly in the 8th neuromere cluster, as well as the anterior region of the 9-11th neuromeres.

Changes in the vesicular zinc pattern following traumatic brain injury

The present study aims at evaluating the significance of zinc ions on the development of brain damage in a model of traumatic brain injury (TBI). The zinc ion specific autometallographic technique, the ZnSe AMG method, using silver enhancement of in vivo–captured zinc ions bound in zinc–selenium nanocrystals was applied to follow changes in the vesicular zinc pattern. Balb/c mice, ZnT3 knockout (ZnT3-Ko) mice, a mouse genetically knocked out for the protein ZnT3 responsible for sequestering zinc into synaptic vesicles, and littermates from the genetically un-manipulated mother type mice, wild type (Wt), were used. The Wt and the Balb/c mice exhibited instantaneously a boost in the zinc staining adjacent to the lesion involving all six neocortical layers. Ultra-structural analyses revealed that the in vivo created ZnSe nanocrystals were still confined to the vesicles of the zinc-enriched (ZEN) neurons in the neuropil. No differences between the Balb/c and Wt mice were seen at any time points. In the ZnT3-Ko mice the ZEN terminals stayed void of AMG grains, but a number of neuronal somata around the lesion became loaded with ZnSe nanocrystals. These silver-enhanced ZnSe nanocrystals were confined to the cytoplasm of the somata and their proximal dendrites. No such soma staining was seen in the Wt or Balb/c mice. We speculate that vesicular zinc may not contribute to neuronal damage following TBI.

Histological and immunocytochemical characterization of neurons located in the white matter of the spinal cord of the pigeon

In the spinal cord of birds a considerable number of neuronal somata is located outside the gray matter. Some of these neurons form segmental marginal nuclei, which lie at the border of the spinal cord near the dentate ligament. In lumbosacral segments these marginal nuclei form accessory lobes which bulge into the vertebral canal. These lobes consist in neurons which are embedded into glia-derived glycogen cells. Furthermore, there are neurons in the white matter near the accessory lobes and numerous paragriseal cells lying in the lateral and ventral funiculus. Glycogen cells are present both in the lobes and in the glycogen body which fills the lumbosacral spinal rhomboid sinus. Immunoreactivity of glial fibrillary acidic protein, a marker of astrocytes, was used to characterize the surrounding of marginal neurons. Astrocytes were numerous in cervical marginal nuclei but rare in accessory lobes. There is cytological (distribution of Nissl substance) and immunocytochemical evidence (immunoreactivity of medium-sized neurofilament, glutamic acid decorboxylase and glutamatergic AMPA receptor subtype GluR2/3) that neurons of the accessory lobes and the nearby white matter are similar, whereas paragriseal cells are different.

Distribution of nitric oxide synthase-containing ganglionic neuronal somata and postganglionic fibers in the rat kidney.

Nitric oxide synthase (NOS)-immunoreactive neurons were identified in the rat kidney by using an antibody against type Ia NOS and the avidin-biotin complex immunoperoxidase method in whole kidneys examined in 100 microns serial sections. The histochemical method for demonstration of the nicotinamide adenine dinucleotide phosphate diaphorase (NADPH-d) was also used to characterize NOS-containing neurons. All somata showing NOS immunoreactivity also displayed NADPH-d activity. The greatest number of neuronal somata were observed in groups at the wall of the renal pelvis and in the angular space formed by the pole of the renal parenchyma and renal pelvic wall. They were also seen at the renal hilus close to the renal artery and along the interlobar vasculature. The size of the neuronal somata in the 35-day-old rat ranged from 13.6 to 34.8 microns, with a mean size of 21.52 +/- 4.81 microns. Seventy percent, however, ranged in size from 17.8 to 26.8 microns. The shape of the neuronal somata also varied, with the majority having an ovoid or round shape. The distribution of the postganglionic fibers was investigated by means of the camera lucida. Postganglionic fibers projected into the wall of the renal pelvis and/or to the interlobar arteries extending to the arcuate arteries and to the beginning of the afferent arterioles. The NOS-immunoreactive neurons may have a vasodilator and relaxing function on the renal pelvic wall and vasculature. In addition, the presence of NOS-containing nerve fibers in nerve bundles, which are known to have predominantly vasomotor and sensory fibers, suggest that they may have a possible modulatory role on renal neural function.

Organization and development of the cingulum: Laminar arrangement of acetylcholinesterase-rich components in rat

The cingulum of the rat is seen to be composed of several distinct fiber and neuronal somal components. In histochemical preparations, three acetylcholinesterase (AChE)-rich fiber zones are noted. The most dorsal originates in the cholinergic cell groups of the basal forebrain, (BF). There is a second, poorly reactive region subjacent to the BF afferent zone. The third, and most ventral zone, has not been described previously. It is operationally dubbed the entocingular fasciculus, ECF. It consists of a moderately dense plexus of AChE-reactive axons and dendrites. In contrast to the regularity and coherence of BF afferents, ECF fibers run in all directions in relation to adjacent cortical (cingulate, sensory-motor), subcortical and transcallosal sites. Knife cut lesions indicate the presence of a substantial proportion of fibers that travel either rostrally or caudally within the ECF itself. The small number of neuronal somata within the cingulum are mostly localized to the ECF. Ultrastructurally, these cells appear to synthesize AChE and form a single type of axo-somatic synapse; synapses are not common in the ECF. Altogether, these observations suggest that the ECF is a conduit for AChE-rich fibers directed towards targets outside of this structure. The AChE reactivity within the ECF first becomes apparent in the second postnatal week, lagging somewhat behind the enzymological maturation of BF afferents. It is concluded that in addition to BF afferents, other AChE-rich fibers travel in the cingulum. A distinctive population of fibers appears to bridge between various cerebral sites via the ECF. These latter observations raise the speculative possibility of a role for the ECF in limbic and sensorimotor cortical interactions.