Number Of Somata Research Articles

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.

Innervation patterns of the cerebral nerves in Haminoea hydatis (Gastropoda: Opisthobranchia): a test for intraspecific variability

This study describes the innervation patterns for the cerebral nerves which project to the cephalic sensory organs (CSOs) in the opisthobranch Haminoea hydatis (Linnaeus 1758) and uses axonal tracing techniques (backfilling) to reveal the central cellular origins for these cerebral nerves. Cell clusters projecting into the cerebral nerves can be defined by their positions in the ganglion relative to other clusters, nerve roots and lobes. The number of cell clusters and the relative sizes of somata are constant in a given cluster, whereas the absolute number of somata and absolute sizes of single somata in a given cluster increase with the size of the animal. Additionally, the invariable morphological characteristics of the cell clusters are used to define criteria for the assessment of possible homology for the clusters innervating the CSOs in Opisthobranchia. The data suggest two different strategies to accommodate the increasing body size; first, the additions of nerve cells and second, the growth of nerve cells.

Dendrites of medial olivocochlear neurons in mouse

Stains for acetylcholinesterase (AChE) and retrograde labeling with Fluorogold (FG) were used to study olivocochlear neurons and their dendritic patterns in mice. The two methods gave similar results for location and number of somata. The total number of medial olivocochlear (MOC) neurons in the ventral nucleus of the trapezoid body (VNTB) is about 170 per side. An additional dozen large olivocochlear neurons are located in the dorsal periolivary nucleus (DPO). Dendrites of all of these neurons are long and extend in all directions from the cell bodies, a pattern that contrasts with the sharp frequency tuning of their responses. For VNTB neurons, there were greater numbers of dendrites directed medially than laterally and those directed medially were longer (on average, 25–50% longer). Dendrite extensions were most pronounced for neurons located in the rostral portion of the VNTB. When each dendrite from a single neuron was represented as a vector, and all the vectors summed, the result was also skewed toward the medial direction. DPO neurons, however, had more symmetric dendrites that projected into more dorsal parts of the trapezoid body, suggesting that this small group of olivocochlear neurons has very different physiological properties. Dendrites of both types of neurons were somewhat elongated rostrally, about 20% longer than those directed caudally. These results can be interpreted as extensions of dendrites of olivocochlear neurons toward their synaptic inputs: medially to meet crossing fibers from the cochlear nucleus that are part of the MOC reflex pathway, and rostrally to meet descending inputs from higher centers.

Immunohistochemistry of neuronal nitric oxide synthase and protein nitration in the striatum of the aged rat.

To ascertain the possible implications of the nitric oxide (NO*) producing system in striatal senescence, and by using immunohistochemistry and image-processing approaches, we describe the presence of the enzyme nitric oxide synthase (NOS), the NADPH-diaphorase (NADPH-d) histochemical marker, and nitrotyrosine-derived complexes (N-Tyr) in the striatum of adult and aged rats. The results showed neuronal NOS immunoreactive (nNOS-IR) aspiny medium-sized neurons and nervous fibres in both age groups, with no variation in the percentage of immunoreactive area but a significant decrease in the intensity and in the number of somata with age, which were not related to the observed increase with age of the striatal bundles of the white matter. In addition, NADPH-d activity was detected in neurons with morphology similar to that of the nNOS-IR cells; a decrease in the percentage of area per field and in the number of cells, but an increase in the intensity of staining for the NADPH-d histochemical marker, were detected with age. The number of neuronal NADPH-d somata was higher than for the nNOS-IR ones in both age groups. Moreover, N-Tyr-IR complexes were observed in cells (neurons and glia) and fibres, with a significant increase in the percentage of the area of immunoreaction, related to the increase of white matter, but a decrease in intensity for the aged group. On the other hand, we did not detect the inducible isoform (iNOS) either in adult or in aged rats. Taken together, these results support the contention that NADPH-d staining is not such an unambiguous marker for nNOS, and that increased protein nitration may participate in striatal aging.

Development of N-methyl-D-aspartate receptor subunit immunoreactivity in the neonatal gerbil cochlear nucleus.

The distribution of immunoreactivity for the ionotropic N-methyl-D-aspartate (NMDA) receptor subunits was mapped in the cochlear nucleus of postnatal day (P) 7, P14, P21, and P28 gerbils. Frozen sections and serial plastic sections of tissue were incubated with antibodies to NMDAR1 (NR1), NMDAR2A (NR2A), NMDAR2A/B (NR2A/B), and NMDAR2B (NR2B). An overall diffuse stain was noted at P7 for NR1 and NR2A/B. Staining of neuronal somata in the dorsal cochlear nucleus molecular layer and fusiform cell layer, the posteroventral cochlear nucleus octopus cell area, and the anteroventral cochlear nucleus increased from P7 to P28. Staining of the neuropil (the unresolved mass of processes and axons, excluding only neuronal somata and distinctly stained proximal dendrites) of the deep dorsal cochlear nucleus and posteroventral cochlear nucleus showed a steady decrease, while molecular layer neuropil remained moderately stained. The NR2A antibody produced a distinctive staining of dendrites in the dorsal cochlear nucleus deep and fusiform cell layers seen first at P14 with increasing dendritic lengths stained at P21 and P28. Giant neurons of the deep dorsal cochlear nucleus were the most conspicuous somata stained by the NR2A. Their stained dendrites spanned much of the dorsal cochlear nucleus deep and fusiform cell layers and even extended into the octopus cell area of the posteroventral cochlear nucleus. Dendritic staining was also present in caudal and rostral posteroventral cochlear nucleus, first distinguishable at P14 and becoming increasingly strong. The Chemicon polyclonal NR2B antibody produced glial staining especially prominent in the caudal posteroventral cochlear nucleus and the dorsal cochlear nucleus fusiform cell layer, most intense at P7 and subsequently decreasing, although not disappearing, in all areas through P28. The Molecular Probes (Eugene, OR) polyclonal NR2B produced a light granular staining pattern over a number of somata but no glial staining. Neuropil staining was not prominent with either NR2B antibody. Differences in changes of neonatal immunoreactivity patterns in different populations of cochlear nucleus neuronal somata and dendrites for NR1, NR2A, NR2A/B, and NR2B suggest that alterations in some receptor composition is occurring over the period spanning the onset of hearing.

Distribution of the endogenous digitalis-like substance (EDLS)-containing neurons labeled by digoxin antibody in hypothalamus and three circumventricular organs of dog and macaque

Endogenous digitalis-like substance (EDLS) is a newly discovered humoral agent which causes sodium-diuresis. EDLS is well known to have inhibitory activity to Na +, K +-ATPase and cross-immunoreactivity to digoxin antibody; however, its precise chemical structure has not yet been determined. We had previously developed a histochemical technique for EDLS, i.e., digoxin-immunohistochemistry, and demonstrated that EDLS was produced in the hypothalamic neurons. In the present study, the distribution of EDLS-containing neurons in the hypothalamus of dog and macaque was investigated using this technique, because anti-EDLS antibody cannot be obtained yet. In both species, EDLS neuronal somata were mainly localized in the paraventricular nucleus and the supraoptic nucleus and its accessory nuclei. A number of somata were also scattered in the other hypothalamic areas. The processes of these neurons ran from the area where the somata were located, through the lateral and basal area of the hypothalamus, to the infundibulum. These nerve fibers with varicosities were associated with the primary capillaries of hypophysial portal veins. A few immunopositive nerve fibers were also seen in the pituitary posterior lobe of both species. Intensive immunoreactivities were observed in the subfornical organ and organum vasculosum laminae terminalis. There were no differences between dog and macaque.

The Gonadotropin-Releasing Hormone Neuronal System of the Male Djungarian Hamster: Distribution from the Olfactory Tubercle to the Medial Basal Hypothalamus

The neuroanatomical distribution and morphology of neurons that produce gonadotropin-releasing hormone (GnRH) in the brain of the postpubertal male Djungarian hamster was studied using light microscopic immunocytochemistry. Analysis of every section from the rostral olfactory tubercle to the medial basal hypothalamus indicate 356 +/- 37 immunoreactive GnRH perikarya per brain (mean +/- SE; n = 4 brains). Over 90% of GnRH cell bodies were found in 6 brain regions; the largest number of somata were located in the medial preoptic area followed by the diagonal band, lateral hypothalamus, lateral preoptic area, lateral septum and anterior hypothalamus. Morphologically, two predominant types of GnRH neurons were identified: unipolar GnRH cells with an ovoid soma and only a single distinct process (about 40% of all GnRH neurons), and bipolar cells with a fusiform-shaped perikaryon. Overall and in most brain regions, the ratio of unipolar to bipolar GnRH perikarya was 2:3 or greater. A significant proportion of GnRH neurons had an unusually "thick" process(es) that exited the soma and tapered gradually. GnRH fibers were evident in most sections, forming dense plexuses in the arcuate nucleus-median eminence, the periventricular region of the third ventricle and organum vasculosum of the lamina terminalis. These findings indicate that the Djungarian hamster is similar to other rodent species, especially the white-footed mouse, in the neuroanatomical distribution of GnRH neurons. The present report provides a working atlas for the rostral ventral forebrain of the postpubertal Djungarian hamster.(ABSTRACT TRUNCATED AT 250 WORDS)

Competition for survival among developing ciliary ganglion cells

1. Functionally different subgroups, each innervating a different part of the peripheral target, were defined within the ciliary population of the avian ciliary ganglion by electrical stimulation of the various ciliary nerve branches. 2. Although neurons innervating defined parts of the peripheral target consistently sent their axons through certain nerves, the technique of retrograde horseradish peroxidase (HRP) transport showed that the ganglion cell bodies were not spatially grouped but distributed throughout the ganglion, both before and after the period of naturally occurring cell death. However, such neurons tended to be clustered into groups of two or greater. 3. Ciliary and choroid populations, however, were found to be for the most spatially separate and recognizable by location and soma size before the period of cell death. Choroid cells did not project out the ciliary nerves even prior to the cell death period, confirming previous observations of selective axon outgrowth in the two populations. 4. Competition for survival was demonstrated within the ciliary population by experimentally removing approximately two-thirds of the neurons by axotomy-induced cell death at stage 32-34 just prior to the normal cell death period. This reduction in the number of competing neurons resulted in rescue of approximately 40% of the neurons that would have died, as assessed both by the number of axon profiles in the remaining intact nerve branch, as well as the number of somata that could be retrogradely labeled from this nerve. 5. It was concluded that many of the neurons that are normally removed during the cell death period are not destined to die, but can be rescued by reducing the number of neurons competing for a limited supply of some aspect of the peripheral target. Further, the postulated interaction with the target was shown to occur relatively late, just prior to the onset of cell death. 6. At the time of the peripheral interaction, the target was found to consist primarily of myoepithelial cells, which had migrated into the target region following the arrival of the ciliary axons. The target per se, therefore, cannot be involved in the selective growth of ciliary axons to the appropriate region. Well-defined synapses were rare, although many axonal endings were observed in close contact with both myoepithelial cells and the sparser differentiated muscle fibers, which increased to account for 60% of the target by the end of the cell death period. 7. Competition was also found to retard the rate of neuronal maturation because intact axons in the partially axotomized ganglion developed more rapidly than control axons, as assessed by axon diameter, conduction velocity, and degree of glial ensheathment. 8. Finally, at least some of the neurons in the partially axotomized ganglion expanded to innervate the peripheral territory of the axotomized branches, suggesting that competition between neurons is involved in the establishment of the observed peripheral innervation pattern.

Cell body locations and axonal pathways of neurons innervating muscles of mastication in the rat.

AbstractIn the rat the size distributions of cell bodies in the trigeminal motor nucleus and of myelinated fibers in the portio minor were bimodal. The size distribution of mesencephalic nuclear somata was unimodal. The number of fibers in the portio minor was approximated by the number of somata in the motor and mesencephalic nuclei. Within the motor nucleus large and small cells were chromatolytic after destruction of the portio minor. Injections of horseradish peroxidase (HRP) into the masseter and temporalis muscles labeled both the large and small neurons in the dorsolateral part of the nucleus. Similar injections into the anterior belly of the digastric and mylohyoid muscles labeled neurons in the ventrolateral part of the nucleus, but these neurons were not among the smallest in the nucleus. Within the mesencephalic nucleus chromatolytic somata occurred only ipsilaterally after unilateral lesions of the portio minor, and in lesser numbers after destroying the portio major. Unilateral injections of HRP into the masseter and temporalis muscles labeled cells in the ipsilateral mesencephalic nucleus and trigeminal ganglion. Labeling of mesencephalic neurons was abolished by lesions of the portio minor. Similar injections into the anterior belly of the digastric and mylohoid muscles labeled cells in the ipsilateral trigeminal ganglion, but not in the mesencephalic nucleus. These results are discussed in light of previous work on the trigeminal system.

A quantitative observation of the human circumvallate taste bud with electron microscope (author's transl)

The whole thickness of the epithelium of the human circumvallate papillae was divided tentatively into three portions from its superior surface, upper (UP), middle (MP) and lower portion (LP). Three transverse sections of circuvallate taste bud in each portion, totally nine sections, were observed and photographed with electron microscope. After constructing photomontages from nine sections magnified in about 2×104 and making contour pictures traced on three components of the taste bud, soma, nerve fiber and intercellular space, morphometrical observations were performed by curvimeter and planimeter.The number of somata examined was 255 at LP, 241 at MP and 292 at UP.The number of nerve fibers measured was 535 at LP, 272 at MP and 239 at UP.The results obtained from observations are as follows;1. The number of somata contacting with nerve fibers was 180 at LP, 162 at MP and 152 at UP.2. The average circumference length of the soma was 9.9 /1 at LP, 13.1 /1 at MP and 11.8 μ at UP.3. The average covering ratio of the soma with nerve fibers was 30.7% at LP, 23.7% at MP and 22.8% at UP.4. The average contact number of the soma with nerve fibers was 4.3 at LP, 3.3 at MP and 3.1 at UP.5. The average contact length of the soma with one nerve fiber was 0.8 μ at LP, 1.2 μ at MP and UP.6. The packing density of somata in the taste bud was 0.22/μ2 at LP, 0.11/μ2 at MP and 0.12/μ2 at UP.The quantitative observation of the human taste bud has not been reported up to date, hough many reports on the qualitative observation with electron microscope were seen. In this respect the quantitative morphometrical analysis employed in present study will be useful in the fields of physiology, histology and clinical medicine.