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Differences in neuronal lipid composition between superior cervical ganglia and nodose ganglia of the rat.

The lipid content and composition of rat superior cervical ganglia containing sympathetic motor neurons and nodose ganglia containing parasympathetic sensory neurons were studied for the first time to elucidate the mechanism of the different effects of exogenous gangliosides on these neurons in the culture medium. The ganglioside content of the superior cervical ganglia was almost 3-times that of the nodose ganglia. Although both ganglia contained GM3, GD3, GD1b and GT1b as major gangliosides, the nodose ganglia additionally contained a significant amount of sialosyllactoneotetraosylceramide LM1 (10% of total sialic acids). Contrasting with nodose ganglia, vagus fiber and dorsal root ganglia of rats, superior cervical ganglia had a higher content of sulfatide than galactosylceramide. The phospholipid content was lower in superior cervical ganglia than in nodose ganglia. Superior cervical ganglia contained less ethanolamine plasmalogen and more phosphatidylcholine than nodose ganglia. Sphingomyelin in superior cervical ganglia contained mainly medium-chain fatty acids, while that in nodose ganglia contained mainly longer-chain fatty acids. Differences in the fatty acid composition of glycerophospholipids were also observed. The results indicate that the properties of neuronal cell membranes from superior cervical ganglia and nodose ganglia are quite different, and that the differences may reflect the physiological roles of these ganglia.

Animals↗

Heterogeneity of ganglia of the guinea pig myenteric plexus: an in vitro study of the origin of terminals within single ganglia using a covalently bound fluorescent retrograde tracer.

Experiments were done to test the hypothesis that individual ganglia of the myenteric plexus of the guinea pig small intestine are heterogeneous with respect to the location of the neurons that provide terminals to them. The myenteric plexus, attached to the longitudinal layer of smooth muscle, was maintained in vitro. Individual ganglia were injected with a variety of potential retrograde tracers by pressure microejection from the tip (20-micron diameter) of a glass micropipette. The fluorescent dye 4-acetoamido, 4'-isothiocyanostilbene-2,2'-disulphonic acid (SITS) was found to be an effective tracer, labeling neuronal perikarya, evidently by retrograde transport. SITS has previously been shown not to cross plasma membranes, but to be covalently bound to the outer surface of that membrane, and to be taken up by nerve terminals to be retrogradely transported to label neuronal cell bodies. SITS fluorescence was found in about 12% of the neurons within the ganglion into which it was injected and also in approximately ten times more neurons in discretely located distant ganglia. No labeling of neurons was found when SITS was injected into the bath or into the smooth muscle below the myenteric plexus. Damage to neural connectives obstructed the labeling of neurons in ganglia distal to the injection site. Individual SITS-injected myenteric ganglia were found to vary greatly in the ratios of intraganglionic SITS-labeled neurons to the total number of neurons within the injected ganglion. The ratios of the number of intraganglionic SITS-labeled neurons to SITS-labeled neurons in distant ganglia projecting to the injected ganglion from elsewhere in the myenteric plexus also varied greatly. More strikingly, individual ganglia differed over a wide range with respect to whether the neurons in distant ganglia that provided them with terminals were situated in the oral, anal, or circumferential direction. Although the majority of projections were found to be from orally located ganglia, individual ganglia were observed that received predominantly or exclusively anal or oral projections. Others received mixtures of terminals from ganglia that were anal, oral, or circumferential. This anatomical heterogeneity in the location of afferent inputs to individual myenteric ganglia is probably reflected in a functional heterogeneity as well and will have to be taken into account in further studies of the physiology of the myenteric plexus. Individual ganglia of the plexus can no longer be taken as anatomically and functionally equivalent to one another.

4-Acetamido-4'-isothiocyanatostilbene-2,2'-disulfo↗

Neurotransmitter organization and connectivity of the basal ganglia in vertebrates: implications for the evolution of basal ganglia.

The basal ganglia in modern mammals, birds and reptiles (i.e. modern amniotes) are very similar in connections and neurotransmitters, suggesting that the evolution of the basal ganglia in amniotes has been very conservative. For example, the basal ganglia in all amniotes possess a dorsal striatum containing two main populations of projection neurons, substance P-containing (SP+) and enkephalin-containing (ENK+) neurons, which have major projections to the dorsal pallidum and the tegmentum (ventral tegmental area and substantia nigra, or VTA/SN). The VTA/SN, in turn, has a major dopaminergic (DA+) projection to the striatum in all amniotes. In this paper, we review these data on the basal ganglia in amniotes and note points of similarity and difference in the functional circuitry of the basal ganglia among amniotes. In addition, we review recent findings on the neurotransmitter organization and connectivity of the basal ganglia in amphibians and fishes, with the goal of assessing whether a basal ganglia showing the same basic features as in amniotes is observed in anamniotes. Published data indicate that in at least two groups of fishes (cartilaginous fishes and lungfishes) and apparently in amphibians, the basal ganglia is present and consists of a distinct striatum and pallidum. The striatum of amphibians, cartilaginous fishes, and lungfishes contain SP+ and ENK+ neurons that seem to project to the pallidum as well as to a brainstem cell group that appears comparable to the VTA/SN of amniotes. Data for ray-finned fishes also suggest the presence of a striatum containing SP+ and ENK+ neurons that projects to VTA/SN-like brainstem cell group. In the basal ganglia of ray-finned fishes, however, a distinct pallidum had not been identified. Finally, the brainstem cell group receiving striatal input in all anamniotes contains DA+ neurons that seem to project to the striatum. The present analysis suggests that a rudimentary basal ganglia was already present in the brain of the ancestral jawed vertebrates. This rudimentary basal ganglia likely consisted of a striatum and a pallidum, and the striatum probably already possessed the same basic connections and some of the same basic cell types as the basal ganglia of modern jawed vertebrates.

Animals↗

Calretinin-immunoreactive nerves in the uterus, pelvic autonomic ganglia, lumbosacral dorsal root ganglia and lumbosacral spinal cord.

Nerves containing the calcium-binding protein calretinin have been reported in several organs but not in female reproductive organs and associated ganglia. This study was undertaken to determine if nerves associated with the uterus contain calretinin and the source(s) of calretinin-synthesizing nerves in the rat (are they sensory, efferent, or both?). Calretinin-immunoreactive nerves were present in the uterine horns and cervix where they were associated with arteries, uterine smooth muscle, glands, and the epithelium. Calretinin-immunoreactive terminals were apposed to neurons in the paracervical ganglia; in addition, some postganglionic neurons in this ganglion were calretinin positive. Calretinin perikarya were present in the lumbosacral dorsal root ganglia, no-dose ganglia, and lumbosacral spinal cord. Retrograde axonal tracing, utilizing Fluorogold injected into the uterus or paracervical parasympathetic ganglia, revealed calretinin-positive/Fluorogold-labeled neurons in the dorsal root and nodose ganglia. Also, capsaicin treatment substantially reduced the calretinin-positive fibers in the uterus and pelvic ganglia, thus indicating the sensory nature of these fibers. The presence of calretinin immunoreactivity identifies a subset of nerves that are involved in innervation of the pelvic viscera and have origins from lumbosacral dorsal root ganglia and vagal nodose ganglia. Though the exact function of calretinin in these nerves is not currently known, calretinin is likely to play a role in calcium regulation and their function.

Animals↗

Unusual autonomic ganglia: connections, chemistry, and plasticity of pelvic ganglia.

The pelvic ganglia provide the majority of the autonomic nerve supply to reproductive organs, urinary bladder, and lower bowel. Of all autonomic ganglia, they are probably the least understood because in many species their anatomy is particularly complex. Furthermore, they are unusual autonomic ganglia in many ways, including their connections, structure, chemistry, and hormone sensitivity. This review will compare and contrast the normal structure and function of pelvic ganglia with other types of autonomic ganglia (sympathetic, parasympathetic, and enteric). Two aspects of plasticity in the pelvic pathways will also be discussed. First, the influence of gonadal steroids on the maturation and maintenance of pelvic reflex circuits will be considered. Second, the consequences of nerve injury will be discussed, particularly in the context of the pelvic ganglia receiving distributed spinal inputs. The review demonstrates that in many ways the pelvic ganglia differ substantially from other autonomic ganglia. Pelvic ganglia may also provide a useful system in which to study many fundamental neurobiological questions of broader relevance.

Animals↗

Some nerve endings in the rat pelvic paracervical autonomic ganglia and varicosities in the uterus contain calcitonin gene-related peptide and originate from dorsal root ganglia.

The pelvic paracervical autonomic ganglia of female rats were studied for a subpopulation of nerve endings that could be derived from sensory nerve fibers. Immunohistochemical staining using an antiserum against the synaptic-terminal protein synapsin I was used to identify terminal boutons, while an antiserum against the neuropeptide calcitonin gene-related peptide was used to reveal a subpopulation of sensory nerve fibers. The uterine cervix was also examined for the existence of calcitonin gene-related peptide and synapsin I immunoreactivity in nerve fiber varicosities. In addition, the location of nerve endings in the paracervical ganglion was compared to that in the superior cervical ganglion. Synapsin I immunoreactivity was present in the paracervical ganglion in abundant boutons around neuron somata and in the cervix in varicose nerve fibers of the myometrium, vasculature and epithelium. Double labeling immunocytochemistry revealed calcitonin gene-related peptide-like immunoreactivity in subpopulations of synapsin I-immunoreactive endings in ganglia and nerve varicosities in the cervix. Injection of a retrograde axonal tracer, fluorogold, into the paracervical ganglion produced labeled neurons in dorsal root ganglia and spinal cord; however, fluorogold-labeled neurons containing calcitonin gene-related peptide immunoreactivity were visualized only in dorsal root ganglia. Injections of fluorogold into the uterine cervix produced labeled neurons in the paracervical ganglion and dorsal root ganglia; however, only those in dorsal root ganglia contained immunoreactivity for calcitonin gene-related peptide. These results suggest that immunoreactivity for calcitonin gene-related peptide is present in a subpopulation of nerve endings in the paracervical ganglion and not merely in fibers of passage. The nerve endings in the ganglion and varicosities in the uterine cervix originate from sensory neurons in dorsal root ganglia. The arrangement of endings in the ganglia could play a role in sensory/autonomic interactions for modulation of visceral activity.

Animals↗

Functional circuitry of the avian basal ganglia: implications for basal ganglia organization in stem amniotes.

Histochemical, pathway tracing, and neuropeptide/neurotransmitter localization studies in birds, reptiles and mammals during the 1970s and 80s clearly showed that the telencephalon in all amniotes consists of a prominent ventrally situated subpallial region termed the basal ganglia, and a large overlying region involved in higher order information processing termed the pallium or cortex. These studies also showed that the basal ganglia in all extant amniote groups possessed neurochemically and hodologically distinct striatal and pallidal territories. More recently, studies of the localization of genes controlling regional brain development have confirmed the homology of the basal ganglia among amniotes. In our ongoing studies, we have identified several aspects of the functional organization of the basal ganglia that birds also share with mammals. These include: (1) an extensive glutamatergic "cortico"-striatal input and distinctive, cell-type specific localization of glutamate receptor subtypes; (2) an extensive, presumptively glutamatergic intralaminar thalamic input to striatal neurons; (3) an extensive dopaminergic input from the midbrain targeting both substance P (SP) type and enkephalin (ENK) type striatal projection neurons, with SP-type striatal neurons seemingly richer in the D-1 type dopamine receptor; and (4) SP+ and ENK+ striatal outputs giving rise to functionally distinct so-called direct and indirect motor output pathways, with the direct pathway having a pallido-thalamo-motor cortex loop and the indirect pathway relaying back to the direct circuit via the subthalamic nucleus. These findings suggest that the major aspects of the cellular organization and functional circuitry of the basal ganglia in stem amniotes were already as observed in living amniotes, as therefore presumably was its key role in movement control. Because the organization of the basal ganglia of anamniotes is clearly less elaborate than in amniotes, and because the basal ganglia and cortex in amniotes are clearly extensively interconnected structures, it seems likely that stem amniotes were characterized by a major step forward in the grade of telencephalic organization of both the basal ganglia and the pallium.

Afferent Pathways↗

[14C]Glucose metabolism in sympathetic ganglia of chicken embryos and in primary cultures of neurons and of other cells from these ganglia.

Metabolism of [1-14C]glucose and [6-14C]glucose was measured in sympathetic ganglia excised from chicken embryos 12-16 days old and in primary cultures of neurons or nonneurons prepared from these ganglia. Some metabolic rates tended to change with the tissue/medium ratio, so this variable had to be controlled. Less C-6 than C-1 od glucose was put out in CO2 by all three types of preparations, indicating operation of the hexosemonophosphate shunt. The C-6/C-1 ratio was greater for the neuronal cultures and for intact ganglia than for the nonneuronal cultures. The C-6/C-1 ratio for the neurons increased with the amount of tissue added to a given volume of incubation medium, in agreement with previous experiments on embryonic dorsal root ganglia (Larrabee, 1978). Per unit of protein, the output of C-1 of glucose in CO2 was higher in both the neuronal and the nonneural cultures than in intact ganglia, whereas that of C-6 was higher in the neuronal cultures and lower in the nonneuronal ones than in the ganglia. The rates of release in lactate of C-1 and C-6 of glucose were 3-5 times higher from both types of cultures than from intact ganglia. The average rates of incorporation of C-1 and C-6 of glucose into tissue constituents were lower in the cultures than in intact ganglia, significantly so for incorporation of C-6 in the nonneuronal cultures.

Animals↗

Induction of cellular transcription factors in trigeminal ganglia of mice by corneal scarification, herpes simplex virus type 1 infection, and explantation of trigeminal ganglia.

In a mouse model for herpes simplex virus type 1 (HSV-1) latency in which the virus was inoculated via the eye after corneal scarification, HSV-1 replicated in corneal epithelial cells and infected the nerve cell endings. HSV-1 reached the trigeminal ganglia by fast axonal transport between 2 and 10 days postinfection (p.i.) and established a latent infection in neuronal cells or replicated and spread to nonneuronal cells. By using in situ hybridization, we showed that cellular transcription factors are stimulated by HSV-1 infection in trigeminal ganglia. This stimulation is biphasic, peaking at 1 and 3 to 4 days p.i. The first peak involves c-jun and oct-1 expression in neurons, and the second involves c-jun, c-fos, and oct-1 expression in neurons and nonneuronal cells. Corneal scarification, alone or followed by infection with UV-inactivated HSV-1, induced monophasic c-jun and oct-1 expression in some neurons of the trigeminal ganglia, with a peak at 1 day p.i. Corneal infection without prior scarification induced c-jun, c-fos, and oct-1 expression in some neuronal and nonneuronal cells of the trigeminal ganglia 2 to 9 days p.i. Explanation of ganglia from latently infected animals resulted in reactivation of the latent virus. Independently of the presence of latent HSV-1 in explanted ganglia, expression of c-fos, c-jun, and oct-1 was induced first in nonneuronal cells, peaking 6 to 10 h postexplantation, and then in neuronal cells, with a peak at 24 h after explantation when expression of viral replicative genes was first detectable. Since ocular HSV-1 infection, corneal scarification, and explantation of trigeminal ganglia all resulted in induction of expression of cellular transcription factors in ganglia, these factors may play a critical role in the permissiveness of cells for HSV-1 replication during acute infection, latency, and reactivation.

Animals↗

Functional anatomy of the basal ganglia. I. The cortico-basal ganglia-thalamo-cortical loop.

This paper reviews some of the recent findings on different aspects of the anatomical organization of the basal ganglia. Attempts have been made to delineate the anatomical substrate of information processing along the cortico-basal ganglia-thalamo-cortical loop. Emphasis has been placed on data obtained with highly sensitive anterograde tract-tracing methods applied to the study of the main axis of the loop, which is composed of the striatum, the pallidum, and the substantia nigra. These findings have highlighted the complexities of the organization of the intrinsic basal ganglia circuitry, which comprises multiple modular units that are distributed according to highly ordered and repetitive patterns. Such an arrangement is well suited to convey cortical information in a highly specific manner throughout the basal ganglia. The basal ganglia circuitry is also designed so as to modulate in a precise manner the neuronal activity of several brain functional systems, which are involved in the direct control of different aspects of psychomotor behavior. Of utmost importance is the action of the basal ganglia on thalamocortical premotor neurons. It is through these neurons, which can be considered as a sort of final common pathway, that the basal ganglia ultimately influence the complex neuronal computation that goes on at cortical level.

Afferent Pathways↗

Expression of B1 and B2 bradykinin receptor mRNA and their functional roles in sympathetic ganglia and sensory dorsal root ganglia neurones from wild-type and B2 receptor knockout mice.

Bradykinin has been implicated in nociception and inflammation. To examine the relative significance of B1 and B2 bradykinin receptor subtypes in sympathetic and sensory ganglia, the electrophysiological effects of bradykinin analogues and the expression of receptor subtype mRNA were examined in wild-type and "B2 knockout" mice from which the B2 receptor gene had been deleted. In wild-type mice the B2 receptor agonist bradykinin depolarized superior cervical ganglia (SCG) and activated inward currents in dorsal root ganglia (DRG) neurones. Responses to the B1 receptor agonist, [des-Arg10]-kallidin, were seen only in SCG that had been pre-treated with interleukins and the peptidase inhibitor captopril, but not in DRG neurones. The up-regulation of responses to [des-Arg10]-kallidin and substance P were blocked by indomethacin and, thus, were dependent upon cyclo-oxygenase activity. The effects of bradykinin were abolished in SCG and DRG's from B2 knockout mice and this was correlated with the absence of B2 receptor mRNA in ganglia from these animals. However, despite the presence of B1 receptor mRNA in interleukin treated SCG from B2 knockout mice, no depolarizing effects of the B1 receptor agonist [des-Arg10]-kallidin were observed. The successful elimination of bradykinin responses and B2 mRNA in sympathetic and sensory ganglia from B2 knockout mice, confirms that B2 receptors are the predominant functional bradykinin receptor subtype in these tissues and that B1 receptor mRNA is expressed in both sympathetic and sensory ganglia from these animals.

Action Potentials↗

Functional anatomy of the basal ganglia. II. The place of subthalamic nucleus and external pallidum in basal ganglia circuitry.

The subthalamic nucleus and the external pallidum (GPe) are classically viewed as part of the so-called indirect pathway, which acts in concert with the direct pathway. The direct and indirect pathways form the conceptual framework of the anatomical and functional organization of the basal ganglia. A review of recent data regarding the connections of the subthalamic nucleus and the GPe has revealed a lack of firm anatomical support for the existence of the indirect pathway. However, newly recognized projections of the subthalamic nucleus and the GPe place these structures on various novel routes that change the conceptual architecture of the basal ganglia circuitry. These new findings force us to modify our view of the functional identity of the subthalamic nucleus and the GPe. In this new perspective, the GPe stands as an additional integrative station, together with the striatum and the internal pallidum and substantia nigra pars reticulata (GPi/SNr), along the main steam of information processing within the basal ganglia circuitry. Because of its crucial position between the input and output stations of the basal ganglia, the GPe can markedly influence the neuronal computation that occurs at GPi/SNr levels. The subthalamic nucleus can still be regarded as a 'control structure' lying alongside the main stream of information processing. However, because of its widespread efferent projections, the subthalamic nucleus exerts its driving effect on most components of the basal ganglia. Its action is mediated not only by the indirect pathway, but by a multitude of mono- and polysynaptic projections that ultimately reach the basal ganglia output cells.

Afferent Pathways↗

Evidence of substance P immunoreactive neurons in dorsal root ganglia and vagal ganglia projecting to the guinea pig pylorus.

The origin of extrinsic substance P fibers in the guinea pig pyloric wall was investigated by combining retrograde axonal tracing and indirect immunofluorescence techniques. After injection of Fast Blue into the pyloric wall labeled cells were found in the T7-T9 dorsal root ganglia and the nodose and jugular ganglia. About 60% of the labeled cells in the dorsal root ganglia contained substance P-like immunoreactivity. After local application of colchicine, a few substance P positive cells were observed in the nodose and jugular ganglia, some of which also contained Fast Blue.

Animals↗

Atrophy of the basal ganglia as the initial diagnostic sign of germinoma in the basal ganglia.

Germ-cell tumors of the central nervous system generally develop in the midline, but the tumors can also occur in the basal ganglia and/or thalamus. However, MR images have rarely been documented in the early stage of the tumor in these regions. We retrospectively reviewed MR images obtained on admission and approximately 3 years earlier in two patients with germinoma in the basal ganglia, and compared them with CT. In addition to hyperdensity on CT, both hyperintensity on T1-weighted images and a small hyperintense lesion on T2-weighted images were commonly seen in the basal ganglia. These findings may be early MRI signs of germinoma in this region, and the earliest and most characteristic diagnostic feature on MRI was atrophy of the basal ganglia, which was recognizable before development of hemiparesis.

Adolescent↗

Ionic behaviors and nerve growth factor dependence in developing chick ganglia. II. Studies with neurons of dorsal root ganglia.

Using intact dorsal root ganglia (DRG) from embryonic (E) chick and measuring 22Na+ accumulation, the authors have recently shown that (i) ionic control by the ganglia has a complete requirement for exogenous NGF between E6 and E10, and (ii) control of ion pump mechanisms independent of exogenous NGF is progressively acquired by these ganglia from E10 to E16. Similar experiments have now been carried out using enriched suspensions of ganglionic neurons to test whether the acquisition of endogenous control by older ganglia was (1) due to the close association between neurons and nonneurons, and (2) correlated with a decreasing need by these neurons for exogenous NGF for survival in culture. In this enriched neuronal population, Na+ accumulation in the absence of NGF increases from E7 to E10, paralleling the increase in Na+ accessible space under ouabain, but then decreases conspicuously between E10 and E16, despite little change in the ouabain-sensitive Na+ space. NGF prevents Na+ accumulation during the early period, and becomes increasingly irrelevant for this behavior in later (after E10) development. K+ movements (traced with 86Rb+) behaved similarly. Active K+ influx (Na+, K+-pump mediated) also increases severalfold between E7 and E10. This K+ influx is sensitive to NGF at E7 and E10 but not at E14, paralleling the observed Na+ and K+ behaviors. These data suggest that the control of Na+, K+-pump performances acquired by these neurons between E10 and E16 represents the development of a neuronal self-sufficiency. This increase in ionic control is not due to an increase in pump molecules or pumping efficiency. No increases in the binding of [3H]ouabain or active K+ influx occur between E10 and E16, when ionic control is developing. The ionic dependence on NGF by the DRG neurons changes with their developmental age along the same temporal pattern displayed by their survival response to NGF in culture.

Age Factors↗

Poststreptococcal acute disseminated encephalomyelitis with basal ganglia involvement and auto-reactive antibasal ganglia antibodies.

Antibasal ganglia antibodies (ABGA) are associated with Sydenham's chorea and pediatric autoimmune neuropsychiatric disorders associated with streptococcal infections. We present 10 patients with acute disseminated encephalomyelitis (ADEM) associated with Group A beta hemolytic streptococcal infection. The clinical phenotype was novel, with 50% having a dystonic extrapyramidal movement disorder, and 70% a behavioral syndrome. None of the patients had rheumatic fever or Sydenham's chorea. Enzyme-linked immunosorbent assay, Western immunoblotting, and immunohistochemistry were used to detect ABGA. Neurological (n = 40) and streptococcal (n = 40) controls were used for comparison. Enzyme-linked immunosorbent assay results showed significantly elevated ABGA in the patients with poststreptococcal ADEM. Western immunoblotting demonstrated ABGA reactivity to three dominant protein bands of 60, 67, or 80 kDa; a finding not reproduced in controls. Fluorescent immunohistochemistry demonstrated specific binding to large striatal neurones, which was not seen in controls. Streptococcal serology was also significantly elevated in the poststreptococcal ADEM group compared with neurological controls. Magnetic resonance imaging studies showed hyperintense basal ganglia in 80% of patients with poststreptococcal ADEM, compared to 18% of patients with nonstreptococcal ADEM. These findings support a new subgroup of postinfectious autoimmune inflammatory disorders associated with Group A beta hemolytic streptococcus, abnormal basal ganglia imaging, and elevated ABGA.

Acute Disease↗

Exogenous silver in dorsal root ganglia, peripheral nerve, enteric ganglia, and adrenal medulla.

Following intraperitoneal (i.p.) or oral administration of silver salts, the anatomic distribution of silver in the peripheral nervous system (PNS) has been studied. The structures examined were dorsal root ganglia, peripheral nerve (N. ischiadicus), enteric ganglia, and adrenal medulla. Four days after an i.p. injection of silver lactate, silver deposits were found in these structures. The silver content remained stable during the observation period (45 days). The localization of silver deposits in the orally treated animals was independent of the administered silver salt (silver nitrate or silver lactate). The silver deposits in neurons and chromaffin cells were located in the cytoplasm. In all organs silver was present in large amounts in connective tissue membranes, macrophage-like cells, vascular basal laminae, and supporting cells. Satellite cells of the dorsal root ganglia were always heavily stained, while less stain was present in Schwann cells of the peripheral nerves. Intracellular deposits were invariably located in lysosomes, whereas extracellular grains were found in connective tissue fibers and basement membranes.

Adrenal Medulla↗

Fetuin expression in the dorsal root ganglia and trigeminal ganglia of perinatal rats.

Fetuin, a fetal plasma glycoprotein, has been shown previously to be present in sub-populations of neurons in the developing central and peripheral nervous system. To gain a more complete description of the time course of the appearance of fetuin during neurogenesis we have examined fetuin immunoreactivity, and the presence of fetuin mRNA, in the developing rat trigeminal and dorsal root ganglia. Fetuin immunoreactivity and its mRNA were first seen at embryonic day 15 in the trigeminal ganglia, and at embryonic day 16 in dorsal root ganglia. In both trigeminal and dorsal root ganglion, fetuin appeared to be present up until around the time of birth, and then again between postnatal days 3 and 16. The results suggest that fetuin first appears at around the time that ganglion cell axons reach their central targets, which is also approximately when the cell-death period begins. The proportion of ganglion neurons that were fetuin immunoreactive at different ages was inversely related to the amount of cell death that is known to occur in these populations, thus it seems that fetuin is more likely to be associated not with dying cells, but with those that survive the cell-death period.

Animals↗