SIF Cells Research Articles

Characterization of metabotropic glutamate receptor 7 and 8 in rat superior cervical ganglion and their changes following chronic intermittent hypoxia

To investigate the expression and localization of metabotropic glutamate receptors 7 and 8 (mGluR7/8) in rat superior cervical ganglion (SCG) and their changes in response to chronic intermittent hypoxia (CIH). We detected the expressions of mGluR7 and mGluR8 in the SCG of 8-week-old male SD rats using immunohistochemistry and characterized their distribution with immunofluorescence staining. The expression of mGluR7 and mGluR8 in the cytoplasm and nucleus was detected using Western blotting. A 6-week CIH rat model was established by exposure to intermittent hypoxia (6% oxygen for 30 s followed by normoxia for 4 min) for 8 h daily, and the changes in systolic blood pressure, diastolic blood pressure and mean arterial pressure were measured. The effect of CIH on expression levels of mGluR7 and mGluR8 in the SCG was analyzed using Western blotting. Positive expressions of mGluR7 and mGluR8 were detected in rat SCG. mGluR7 was distributed in the neurons and small fluorescent (SIF) cells with positive staining in both the cytoplasm and nuclei, but not expressed in satellite glial cells (SGCs), nerve fibers or blood vessels; mGluR8 was localized in the cytoplasm of neurons and SIF cells, but not expressed in SGCs, nerve fibers, or blood vessels. Western blotting of the nuclear and cytoplasmic fractions of rat SCG further confirmed that mGluR7 was expressed in both the cytoplasm and the nucleus, while mGluR8 exists only in the cytoplasm. Exposure to CIH significantly increased systolic blood pressure, diastolic blood pressure and mean arterial pressure of the rats (all P < 0.001) and augmented the protein expressions of mGluR7 and mGluR8 in the SCG (P < 0.05). mGluR7 and mGluR8 are present in rat SCG but with different localization patterns. CIH increases blood pressure of rats and enhanced protein expressions of mGluR7 and mGluR8 in rat SCG.

Neurochemical characteristics of paracervical ganglion in the pig

A study on the presence of the selected biologically active substances in nerve structures of the paracervical ganglion in the pig was performed with the use of immunofluorescence and RT-PCR. Immunohistochemical methods revealed that 23% of paracervical ganglion (PCG) neurons contain both tyrosine hydroxylase (TH) and dopamine &amp;beta;-hydroxylase (D&amp;beta;H) and that the remaining 77% contain choline acetyltransferase (ChAT) and vesicular acetylcholine transporter (VAChT). 73% of TH/D&amp;beta;H neurons contained neuropeptide Y (NPY) and 8% contained somatostatin (Som). All ChAT/VAChT positive neurons contained vasoactive intestinal polypeptide (VIP), 87% of them contained Som, 76% contained NPY and 32% contained neuronal nitric oxide synthase (nNOS). Galanin (Gal) was found only in small cells, which were thought to be SIF cells. No pituitary adenylate cyclase-activating polypeptide (PACAP)- or substance P (SP)-positive neurons were found in PCG. Some areas of PCG contained dense plexuses of ChAT- and VAChT-positive nerve fibres. In the ganglion small number of TH-, nNOS-, NPY-, VIP-, Gal-, PACAP-, Som- and SP-positive nerve fibres was also visible. RT-PCR detected the presence of mRNA for TH, ChAT, nNOS, NPY, VIP, Gal and Som, which were visualised as clearly discernible bands on a gel. In cases of PACAP and SP only weak bands were observed.

Macro- and microstructural organization of the rabbit's celiac-mesenteric ganglion complex ( Oryctolagus cuniculus)

The macro- and microstructures of the rabbit celiac-mesenteric ganglion complex are described in 20 young animals. We found ten celiac ganglia, twenty-seven cranial mesenteric ganglia and eleven celiac-mesenteric ganglia. The celiac ganglia had a rectangular shape in nine cases (90%) and a circular one in one case (10%). The cranial mesenteric ganglia presented triangular (66.7%), rectangular (11.1%), L-shape (18.5%) and semi-lunar (3.7%) arrangements. The celiac-mesenteric ganglia were organized in three patterns: a single left celiac-mesenteric ganglion having a caudal portion (72.7%); celiac-mesenteric ganglia without a caudal portion (18.2%) and a single celiac-mesenteric ganglion with two portions: left and right (9.1%). The microstructure was investigated in nine celiac-mesenteric ganglia. The results showed that the celiac-mesenteric ganglion is actually a ganglion complex constituted of an agglomerate of ganglionic units separated by nerve fibers, capillaries and septa of connective tissue. Using the semi-thin section method we described the cellular organization of the celiac-mesenteric ganglion complex. Inside of each ganglionic unit, there were various cell types: principal ganglion neurons (PGN), glial cells (satellite cells) and SIF cells (small intensely fluorescent cells or small granular cells), which are the cytologic basis for each ganglionic unit of the rabbit's celiac-mesenteric ganglion complex.

Does the head rule the heart?

In a 70-year lifetime an average human heart beats more than 2.5 billion times, and every beat is strongly influenced by the CNS through the actions of the sympathetic and parasympathetic nervous systems. After more than a century of research on the nervous input to the heart there are still huge gaps in our knowledge of even the basic neuronal circuitry involved. Much attention has focussed on the parasympathetic nervous system, which both listens and talks to the heart via the vagus nerve. Axons of the vagus nerve synapse onto neurones in ganglia very close to the heart, and these neurones themselves then innervate the heart. Retrograde tracers applied to the heart have shown, not without controversy, that the source of these vagal axons is the medulla oblongata, predominantly in the nucleus ambiguus (NA), but also in the lateral part of the dorsal vagal nucleus (DVN), and the area of reticular formation between the two nuclei. The differential localization of neurones in brainstem nuclei led to suggestions that each group has a different role in the control of the heart. It is clear that cardiac projecting neurones in the DVN have slowly conducting unmyelinated C-fibre axons while those in the NA have myelinated B-fibre axons. Selective stimulation of these B and C-fibres have differential effects on the heart (see Ref. 1xSelective stimulation of cardiac vagal C fibres in anaesthetised cats, rats and rabbits. Jones, J.F.X. et al. J. Physiol. 1995; 489: 203–214Crossref | PubMed | Scopus (57)See all ReferencesRef. 1). However, it is not clear how these different effects arise.A recent publication by Cheng and Powley2xNucleus ambiguus projections to cardiac ganglia of rat atria: an anterograde tracing study. Cheng, Z. and Powley, T.L. J. Comp. Neurol. 2000; 424: 588–606Crossref | PubMedSee all References suggests that B and C fibres in the vagus nerve exhibit their distinct effects on the heart through striking target specificity of vagal axons in the cardiac ganglia. Axons of cardiac projecting vagal neurones were labelled by injecting the anterograde tracer DiI into the brainstem, the size and distribution of the labelled axons in the ganglia of the atria were examined using confocal microscopy. They found that vagal axons arising from the nucleus ambiguus were large calibre (i.e. consistent with being B-fibres) and formed dense basket-like innervation of the principal neurones in the cardiac ganglia. However, these axons rarely contacted the other type of neurone in the ganglia, the small intensely fluorescent neurones (SIF cells). This was a remarkable contrast to previous experiments, where injections of the other main source of cardiac projecting vagal neurones, the DVN showed that the major target for the small calibre (C) fibres were predominantly the SIF cells.This report of the specific cardiac projection patterns of the vagus nerve B and C-fibres suggests that the vagus nerve influences processing and integration of information from the brain actually taking place in the neuronal circuitry in the ganglia close to the heart. It is probable that some processing takes place since the SIF cells are interneurones which also receive information direct from the heart, while the principal cells project directly to the heart. One might now ask if the head does rule the heart, or whether the neuronal circuitry in the cardiac ganglia make their own version of the messages via information processing.

A target specific pathway from nitric oxide synthase immunoreactive preganglionic sympathetic to superior cervical ganglion neurons innervating the submandibular salivary gland

The correlations between nitric oxide synthase (NOS)-immunoreactive (NOS-ir) preganglionic sympathetic neurons (PSNs) in the thoracic spinal cord and the neurons in the superior cervical ganglia (SCG) were studied with special reference to target specificity. NOS-ir neurons were distributed in the intermediate gray of the spinal cord and most numerous in the intermediolateral subnucleus of the PSNs. NOS-ir PSNs received direct synaptic contacts from tyrosine hydroxylase-ir, 5-hydroxytryptamine-ir, γ-amino butyric acid-ir, and phosphate-activated glutaminase-ir axons. A majority of PSNs projecting to SCG were NOS-ir but some were NOS-negative. Large SCG neurons surrounded by a dense network of NOS-ir axons from PSNs projected to the submandibular salivary gland. NPY-ir small SCG neurons devoid of NOS-ir PSN innervation projected to blood vessels. SIF cells in the SCG were NOS-negative and provided with a meshwork of NOS-ir axons. The present results suggest a subpopulation of SCG neurons may be concerned with a distinct functional category in the rat under the influence of NOS-ir preganglionic sympathetic neurons.

Peripheral chemosensitivity and central integration: neuroplasticity of catecholaminergic cells under hypoxia.

The plasticity of catecholaminergic cells within the carotid body, brainstem and sympatho-adrenal system was analyzed in rats subjected to normobaric hypoxia (10% O2) lasting up to 3 weeks. Long-term hypoxia elicited structural, neurochemical and phenotypic changes in carotid body and sympathetic ganglia (SIF cells), and stimulated the norepinephrine turnover in A2 neurons located caudal to the obex, the area where the chemosensory nerve fibers end. Chemodenervation abolished central alterations. Adaptive mechanisms for increasing norepinephrine biosynthesis in hypoxia involved changes in activity of pre-existing tyrosine hydroxylase, the rate-limiting enzyme of catecholamine biosynthesis, and induction of new tyrosine hydroxylase protein. These neurochemical changes occurred after sustained hypoxia only, suggesting that noradrenergic neurons are involved in the central chemoreceptor pathway during sustained hypoxia but are not essential for regulatory responses to acute hypoxia. Acute hypoxia elicited the expression of c-Fos protein in neurons located in nucleus tractus solitarius that were not catecholaminergic. Noradrenaline released under long-term hypoxia could play a neuromodulatory role in ventilatory acclimatization. Cardiovascular responses to hypoxia are mediated by changes in sympatho-adrenal outflow, different according to the target organ. Cardiac sympathetic output and adrenal secretion were stimulated independently of carotid body chemoafferents. Early postnatal hypoxia induced long-term neurochemical changes in carotid body, brainstem and sympathetic efferents that may reveal alterations in development of neurons involved in the chemoreceptor pathway.

Origin and morphogenesis of neurons in the frog cardiac ganglion.

This paper reviews the cellular events underlying the formation of the cardiac ganglion in the frog. The first neurons become postmitotic at the end of embryogenesis and begin differentiating in a functioning heart. Neuronal precursors in the heart continue dividing and differenting at least through the beginning of metamorphosis. Since cell death is not a characteristic of early cardiac ganglion development, proliferation and differentiation alone regulate the addition of neurons to the heart. As new neurons are added, their position is unique and reflects their time of origin. The developmental addition of new neurons to the ganglion is neither time nor stage dependent, but matches the size of the growing heart, even into adult life. During this period, the shape and polarity of cardiac neurons is established through elimination of supernumerary axons that initially extend throughout the heart. The temporal and spatial accumulation of cardiac SIF cells occurs in parallel with cardiac neurons and may indicate a common mechanism underlying the origin of these neural crest derivatives. These studies contribute to our understanding of the cellular processes underlying the development of this important autonomic control mechanism and provide the background for current studies on the regulation of cardiac neurogenesis.

Synaptic vesicle proteins in cells of the sympathoadrenal lineage

The cells of sympathoadrenal lineage display different characteristics after differentiation, although they stem from the same neural crest precursor during embryonic development. In the present study we compared the distribution patterns of several synaptic vesicle proteins in the superior cervical ganglion (SCG) and the adrenal medulla. Using indirect immunofluorescence combined with confocal laser scanning microscopy, it was observed that antisera against integral synaptic vesicle membrane proteins (SV2, synaptotagmin I, synaptobrevin II and synaptophysin) induced strong immunoreactivities in these cells, but anti-synaptobrevin I caused only a faint fluorescence. Immunoreactivities of the synaptic vesicle-associated proteins Rab3a and SNAP25 were also observed in the cells. Synapsin-Ia-reactive material appeared absent from chromaffin cells but present in small amounts in sympathetic neurons in the SCG and iris terminals. On the other hand, synapsin IIa immunoreactive material was strong in most SCG neurons and in adrenergic iris terminals. The neural specific clatrin light chain was detected in the SCG cells and in ganglion cells of the adrenal, but only weak traces could be observed in chromaffin cells. One of the vesicular monoamine transmitter transporters, VMAT2, which is expressed in catecholamine neurons in the brain stem, was observed in most cells in the SCG and also in groups of cells in the adrenal medulla, where the VMAT2-positive small chromaffin cells were PNMT-negative. SIF cells in the SCG contained most of the synaptic vesicle proteins investigated. The results show that after differentiation, sympathetic neurons, SIF cells and adrenal chromaffin cells still share many vesicle proteins even though their physiology is different.

5-Hydroxytryptamine-immunoreactive nerve fibers in the rat and porcine prevertebral sympathetic ganglia: effect of precursor loading and relation to catecholaminergic neurons

Localization of 5-hydroxytryptamine immunoreactivity was studied in the rat coeliac-superior mesenteric ganglion complex and in the porcine superior and inferior mesenteric ganglia by the indirect immunofluorescence technique. In normal rats, only 5-hydroxytryptamine immunoreactive SIF cells were seen in the coeliac-superior mesenteric ganglion complex. In the rats, pretreated with a 5-hydroxytryptamine precursor, l-tryptophan, and with a monoamine oxidase inhibitor, nialamide, a large number of 5-hydroxytryptamine-immunoreactive nerve fiber terminals were detected. In normal porcine superior and inferior mesenteric ganglia, intense 5-hydroxytryptamine immunoreactivity was found in numerous nerve fibers which were located around tyrosine hydroxylase-immunoreactive principal neurons. The origin and function of these fibers are discussed.

Effects of decentralization on the levels of GAP-43 and p38 (synaptophysin) in sympathetic adrenergic neurons: a semi-quantitative study using immunofluorescence and confocal laser scanning microscopy

The distribution of GAP-43 in superior cervical ganglion (SCG) and iris were studied in normal animals and following decentralization using immunofluorescence and confocal laser scanning microscopy (CLSM). GAP-43-like immunoreactivity (LI) was compared with p38 (synaptophysin)-LI, and tyrosin hydroxylase (TH)-LI. In the control SCG, GAP-43-LI and p38-LI were mainly localized in nerve terminals around the principal neurons. The neuronal perikarya were negative for GAP-43, but positive for p38 in a perinuclear zone, as well as positive for TH. SIF cells (Small Intensely Fluorescent cells, ganglionic interneurons) were positive for GAP-43, TH and p38. One day after decentralization, GAP-43-LI and p38-LI in nerve terminals around principal neurons had disappeared. Some of the principal neurons showed a weak GAP-43-immunoreactivity. Three days post-decentralization, GAP-43- and p38-positive nerve terminals around the neurons had reappeared in considerable numbers and the intra-ganglionic nerve bundles were positive for both antibodies. In the control irides, GAP-43-LI and p38-LI were distributed in a varicose pattern in the nerve bundles, around blood vessels and in the network of terminals. Double labelling studies showed that GAP-43-LI was colocalized with TH-LI and p38-LI. The network of terminals in the dilator plate of the irides was quantified by measuring the fluorescence intensity of randomly selected areas, using CLSM. Three days after decentralization the intensity of GAP-43-LI and p38-LI had significantly increased. TH-LI had decreased 8 days after decentralization. The results indicate that GAP-43-LI and p38-LI are normally present in the nerve fibers and terminals of both pre- and post-ganglionic neurons in adult rats. The expression of GAP-43-LI and p38-LI in post-ganglionic neurons is preganglionically regulated, as indicated by the increased expression after decentralization. The expression of p38 in these neurons is probably regulated via mechanisms that are separate from those which regulate GAP-43, since it showed a different time course than that of GAP-43-LI.

An immunoelectron microscopic study of methionine-enkephalin structures in cat prevertebral ganglia

Methionine-enkephalin-like immunoreactivity was detected in presynaptic nerve fibers and SIF cells in cat prevertebral ganglia. The immunoreactive nerve fibers contained a mixture of numerous small clear vesicles and a few large vesicles; the immunoreactivity was only confined to the large vesicles. Most of the immunoreactive fibers were in apposition with non-immunoreactive neuronal profiles, without any detectable synaptic membrane specializations. The other immunoreactive fibers formed synaptic contacts mainly with nonimmunostained dendrites and to a lesser extent with axons and neuronal soma. The characterization at the ultrastructural level of the enkephalin-like immunoreactive structures is discussed as regards the modalities whereby opiates may be involved in sympathetic ganglionic transmission.

Immunohistochemical demonstration of galanin-, and galanin message-associated peptide-like immunoreactivities in sympathetic ganglia and adrenal gland of the guinea pig.

Using the indirect immunofluorescence method, the distribution of galanin (GAL)- and galanin message-associated peptide (GMAP)-like immunoreactivities (LI) were studied in sympathetic ganglia and the adrenal gland of the guinea pig. A rather dense network of GAL-immunoreactive nerve fibers was found in the inferior mesenteric ganglion (IMG) and in the superior mesenteric pole of the celiac-superior mesenteric ganglion complex (C-SMG). The celiac pole of the C-SMG, the stellate ganglion, and the superior cervical ganglion contained fewer, mostly scattered fibers. SIF-cells in prevertebral and paravertebral ganglia contained GAL-LI, as did the adrenal medullary cells. The GAL fibers in the IMG surrounded mainly principal ganglion cells containing somatostatin-immunoreactivity (SOM-IR), whereas fewer fibers were seen around neuropeptide Y (NPY) cells and cells in which SOM and NPY coexisted. Application of colchicine or vinblastine onto the IMG did not result in the appearance of GAL-IR in the principal ganglion cells. In denervation experiments it was revealed that most of the GAL fibers reach the IMG via the lumbar splanchnic nerves. GAL-IR appears to be colocalized with substance P (SP) in fibers of the IMG, indicating an origin of the GAL-containing fibers in dorsal root ganglia (DRG). This conclusion was supported by the finding in lumbar DRGs of GAL-positive cell bodies that contained SP. The role of GAL in prevertebral ganglia is unclear. It may be suggested that GAL modulates the slow, long-lasting membrane depolarization of the principal ganglion cells caused by SP in the primary afferents related to the IMG. GMAP-LI was detected in SIF cells and adrenal medullary cells in which GMAP-LI parallels the immunoreactivity of GAL. GMAP-LI was not observed in neuronal cell bodies or nerve fibers of the ganglia.

Sympathetic and parasympathetic ganglia express non-NMDA type glutamate receptors: distinct receptor subunit composition in the principle and SIF cells

The presence of non-NMDA glutamate receptors in the rat sympathetic and parasympathetic ganglia was examined by immunocytochemistry using specific antibodies against AMPA-type excitatory amino acid receptor subunits (GluR1–4). Three kinds of antibodies specific to the GluR1, GluR2 and 3, and GluR4 subunits were used. The superior cervical ganglion and pterygopalatine ganglion were examined as representatives of sympathetic and parasympathetic ganglia. In the superior cervical ganglion, GluR1- and GluR2/3-like immunoreactivity was observed in most principal neurons and SIF cells. In contrast, GluR4-like immunoreactivity was not observed in the principal cells; however, SIF cells exhibited intense immunoreactivity of GluR4. In the pterygopalatine ganglion, the profile of the immunoreactivity was similar to that seen in the superior cervical ganglia. The subunit compositions between the principal cells and SIF cells were different, whereas the compositions in cell species involved in the autonomic ganglia, sympathetic and parasympathetic ganglia were identical. This suggests that glutamate is another important preganglionic transmitter together with acetylcholine, and the responses elicited in the principal cells and SIF cells might be different because of the difference in subunit composition.

Molecular control of cell fate in the neural crest: the sympathoadrenal lineage.

Over the past five years, new insights have been gained into the biology of the SA lineage. These advances have been powered by the development of immunologic methods to isolate embryonic SA progenitors from fetal adrenal glands and sympathetic ganglia. Analysis of these embryonic progenitors has confirmed many of the ideas derived from earlier studies of postnatal cells, but has necessitated several revisions in our thinking, as well. First, embryonic SA progenitors appear to be distinct from mature SIF cells, a cell type initially postulated to be the central intermediate in the SA lineage. Second, FGF, not NGF, appears to be an important early influence on neuronal fate; NGF responsiveness appears relatively late in differentiation. Third, the development of both sympathetic neurons and adrenal chromaffin cells is not a one-step process, but rather involves a series of events, in which the cells change their responsiveness to growth factors and glucocorticoids. Fourth, emerging circumstantial evidence suggests that SA progenitors may have additional developmental potentials. Finally, new insights have been gained into the molecular mechanisms that underlie both the differentiation of SA progenitors and their determination from earlier multipotent neural crest cells. These advances have made the SA progenitor a well-defined system for studying the molecular control of cell fate in a vertebrate neurogenic precursor cell. The analysis of the SA lineage at the cell biological level has raised several interesting molecular questions for future investigation. In the neuronal branch of the SA lineage, how is the acquisition of NGF-responsiveness and NGF-dependence controlled, and what is the relationship of these events to the expression of p140trk and p75? In the chromaffin branch of the pathway, which molecules control the timing of PNMT expression? In the uncommitted SA progenitor, what is the molecular basis of the antagonism between the competing neuronal and chromaffin pathways of differentiation, and how does commitment to neuronal differentiation occur? Can SA progenitors differentiate to enteric neurons in vitro, and which differentiation and survival factors control this phenotype, as well as the other classical neurotransmitter and neuropeptide phenotypes expressed by SA derivatives? What are the roles of MASH1 and other regulatory genes in controlling early stages in neural crest cell determination, and how is the expression of these molecules in turn controlled? How much of the genetic regulatory network controlling neuronal differentiation in Drosophila has been conserved in vertebrates?(ABSTRACT TRUNCATED AT 400 WORDS)

Combined Trypan Blue and Glyoxylic Acid-Induced Catecholamine Fluorescence in the Female Rat Urinary Bladder After Distension

The effect of short-term urinary bladder distension on bladder perfusion and adrenergic innervation was studied in Sprague-Dawley rats. Distension was induced for three hours by forced diuresis and balloon obstruction. A 2% solution of trypan blue was injected into the tail vein 12, 24, 36 and 48 hours after distension and the animals were killed 5-10 min after the injection. Whole thick biopsies were taken from the dome, anterior body and base. A combination of trypan blue and catecholamine fluorescence (GIF method) was used to correlate the distension induced changes in blood vessel perfusion and permeability with changes in adrenergic innervation. Both ischaemic damage and adrenergic hypoinnervation were observed after distension. Later marked extravasation of trypan blue was observed in the whole bladder after 12 hours and after 24 hours distension the dome was almost necrotic in appearance and highly ischaemic. After 36 hours a few exploded small, intensely fluorescent cells (SIF cells) were found to be scattered along the blood vessels, and degranulated mast cells had invaded the anterior body and dome. The adrenergic hypoinnervation reached its maximum 48 hours after distension. The hypoinnervation and possibly also the damage to SIF cells, would seem to be related to ischaemia during distension, probably attributable in turn to overstretching of the organ and its blood vessels. This may provide an explanation for the prolonged micturition problems found after bladder overdistension.

Role of the carotid sinus nerve and of dopamine in the biochemical response of sympathetic tissues to long-term hypoxia.

The sympathetic nervous system is known to react to hypoxia, but the response is not unitary and is dependent on hypoxic features (severe or moderate hypoxia, acute or chronic exposure), on the sympathetic nerve or tissue considered and on the state of animals (conscious or anesthetized) (Lee et al. 1987; Fitzgerald et al. 1990). Moreover, the mechanisms controlling the response of the sympathetic nervous system remain poorly understood and seem also highly dependent on tissues and on hypoxic conditions. Two components may be possible candidates for this regulation: one related to neural pathways coming from carotid bodies, and the other related to local dopaminergic events. In fact, previous data report that stimulation of carotid chemoreceptors by hypoxia elicits, or not, a sympathetic response indicating the involvement, or not, of a carotid chemoreceptor reflex (Matsumoto et al. 1987a, 1987b; Fukuda et al. 1989; Biesold et al. 1990; Fitzgerald and Deghani, 1990). As to concern dopamine (DA), it is able to induce an inhibitory electrophysiological and biochemical response of the postganglionic noradrenergic neurones, both in vitro and in vivo (Libet and Owman, 1974; Hanbauer, 1976; Ip et al., 1983; Brokaw et al., 1987). The role of DA located in the SIF cells of sympathetic ganglia may be evoked in this control.KeywordsSubmaxillary GlandCarotid BodySuperior Cervical GanglionModerate HypoxiaCarotid Sinus NerveThese keywords were added by machine and not by the authors. This process is experimental and the keywords may be updated as the learning algorithm improves.

Differential effect of guanethidine on dopamine and norepinephrine in rat peripheral tissues.

The changes of dopamine (DA) and norepinephrine (NE) were investigated in rat peripheral tissues after guanethidine treatment (50 mg/kg i.p. five days each week) during one week (group 1, n = 10, five injections) and during 2.5 weeks (group 2, n = 8, 13 injections). Guanethidine greatly reduced NE levels in all the analyzed tissues but only partially depleted DA in kidney, bladder, stomach, intestine, lung and liver and in sympathetic ganglia. The differential pattern of changes between DA and NE induced by guanethidine suggests that peripheral DA is distributed in several neuronal or non-neuronal pools, whose presence, nature and contribution varies in the different tissues. Both noradrenergic cell bodies and small intensely fluorescent cells (SIF cells) can contribute to the DA in the superior cervical ganglion. Noradrenergic neurons seem to be the main sources of DA in seminal vesicles, vas deferens, heart and spleen. In addition to noradrenergic nerves, extraneuronal sources could account for a meaningful portion of DA in kidney, gastrointestinal tract, lung and liver. The bladder is the peripheral tissue where DA exhibits the highest resistance to the neurotoxin. Accordingly, these tissues may provide meaningful sources of non-precursor DA pools.

Complementary histochemical observations on sympathetic ganglia, especially the coeliac plexus of the frog.

The localization of four biologically active peptides was studied by immunohistochemistry in the coeliac plexus and in the first ganglion of the frog sympathetic chain. Perineuronal preganglionic apparatuses reacting with anti-LH-RH were found in both ganglia. Counts of neurons provided with such an apparatus and of neurons devoid of it led to the conclusion that almost all small neurons (diameter 35μm) must be divided into two groups: about 25% are provided with an apparatus, and the others not. In the coeliac plexus the distribution of certain peptides is different from that of the paravertebral ganglion. The coeliac plexus contains more neurons provided with a pericellular reacting with anti-substance P than Paravertebral ganglia. Moreover, the coeliac plexus contains numerous SIF cell reactive with anti-met enkephalin and anti-neuropeptide Y, and some reactive with anti-LH-RH and anti-substance P, which were not encountered in other ganglia.

Sympathetic ganglia and hypoxia: biochemical evidence for chemosensitive SIF cells

Sympathetic ganglia and hypoxia: biochemical evidence for chemosensitive SIF cells

The responsiveness of SIF cells in the rat superior cervical ganglion to prolonged hypoxia

The responsiveness of SIF cells in the rat superior cervical ganglion to prolonged hypoxia