GABA- and glutamate-immunoreactive synapses on sympathetic preganglionic neurons projecting to the superior cervical ganglion

Our previous work suggests that virtually all of the synapses on sympathetic preganglionic neurons projecting to the rat adrenal medulla are immunoreactive for either the inhibitory amino acid, gamma-aminobutyric acid (GABA) or the excitatory amino acid, L-glutamate. To investigate whether or not this is true for other groups of sympathetic preganglionic neurons, and to determine whether or not the proportion of inputs containing each type of amino acid neurotransmitter is the same for different groups of sympathetic preganglionic neurons, we retrogradely labelled rat and rabbit sympathetic preganglionic neurons projecting to the superior cervical ganglion and used post-embedding immunogold on ultrathin sections to localise GABA- and glutamate-immunoreactivity. The cell bodies and dendrites of both rat and rabbit sympathetic preganglionic neurons projecting to the superior cervical ganglion received synapses and direct contacts from nerve fibres immunoreactive for GABA and from nerve fibres immunoreactive for glutamate. In the rat, GABA was present in 48.9% of the inputs to sympathetic preganglionic neurons projecting to the superior cervical ganglion, and glutamate was present in 51.7% of inputs. Double immunogold labelling for glutamate and GABA on the same section, as well as labelling of consecutive serial sections for the two antigens, indicated that GABA and glutamate occur in separate populations of nerve fibres that provide input to rat sympathetic preganglionic neurons projecting to the superior cervical ganglion. We now have shown that GABA or glutamate is present in virtually all of the inputs to sympathetic preganglionic neurons projecting to the superior cervical ganglion and in essentially all of the inputs to sympathetic preganglionic neurons supplying the adrenal medulla. These findings are consistent with the hypothesis that all fast synaptic transmission in central autonomic pathways may be mediated by either excitatory or inhibitory amino acids. Furthermore, we showed a statistically significant difference in the proportion of glutamate-immunoreactive inputs between sympathetic preganglionic neurons projecting to the superior cervical ganglion and sympathoadrenal neurons (data from Llewellyn-Smith et al. [Llewellyn-Smith, I.J., Phend, K.D., Minson, J.B., Pilowsky, P.M., Chalmers, J.P., 1992. Glutamate immunoreactive synapses on retrogradely labelled sympathetic neurons in rat thoracic spinal cord. Brain Res. 581, 67-80]), with preganglionics supplying the adrenal medulla receiving more excitatory inputs than those supplying the superior cervical ganglion. This increased excitatory input to sympathoadrenal neurons may explain the predominant activation of these neurons following baroreceptor unloading.     

Oxytocin innervation of spinal preganglionic neurons projecting to the superior cervical ganglion in the rat

The paraventricular nucleus of the hypothalamus is a major integrative nucleus for relaying information from the suprachiasmatic nucleus to the autonomic system. The precise pathway by which this information can influence autonomic functions, such as melatonin synthesis in the pineal gland, is not clear. In the present study, we used a retrograde tracer injected in the superior cervical ganglion to identify spinal preganglionic neurons. One of the main neurotransmitters present in descending projections of the paraventricular nucleus of the hypothalamus, oxytocin, was detected with immunocytochemistry to visualise possible contacts with the neurons located in the intermediolateral column of the spinal cord and projecting to the superior cervical ganglion. Although many appositions could be seen at the light-microscopic level, this abundance could not be confirmed at the electron-microscopic level. The implications of these observations for the overall timing message received by the spinal preganglionic neurons are discussed.     

Changes in the morphology of sympathetic preganglionic neurons parallel the development of autonomic dysreflexia after spinal cord injury in rats

Following spinal cord transection (SCT), sensory input to the spinal cord causes increases in arterial pressure that are small in rats 1 week after SCT, but become large and well established by 2 weeks. Moreover, sympathetic preganglionic neurons (SPNs) undergo atrophy by 1 week after SCT, and regeneration of these neurons may be an important factor in the etiology of this autonomic dysreflexia. Therefore, we examined the morphology of SPNs 2 weeks after SCT using retrograde transport of the cholera toxin subunit B. The dendritic arbors of SPNs were re-established by 2 weeks after SCT. This regeneration parallels the time course of the development of autonomic dysreflexia after cord injury in the rat, and may play a role in initiating this disorder.     

Distribution and immunohistochemical characteristics of neurons in the porcine caudal mesenteric ganglion projecting to the vas deferens and seminal vesicle

The subperiosteal browlift and midface lift combination is a total mobilization of the composite full-thickness soft tissues from the bony skeleton with superior suspension. The object is to correct midfacial ptosis and the "tired" look of the lateral eyelids. It is done in conjunction with a browlift so that a composite correction of the upper and midface is achieved. When indicated, a modified lower cheeklift and the usual procedures for correcting neck deformities are utilized in combination. We believe the procedure is safe and the results reported are natural and long-lasting. This review of 130 cases also stresses technical aspects and the safety of the procedure.     

Localization of preganglionic neurons of the accessory ciliary ganglion in the midbrain: HRP and WGA-HRP studies in the cat

Localization of preganglionic neurons of the accessory ciliary ganglion (ACG), including ectopic intraocular ganglion cells, was investigated in the cat with the aid of horseradish peroxidase (HRP) and HRP-conjugated wheat germ agglutinin (WGA-HRP) methods. When HRP or WGA-HRP was injected into the anterior and posterior chambers of the eye, no retrogradely labeled cells were found in the visceral oculomotor nuclei, although most neurons of the ACG and the main ciliary ganglion (CG) were intensely labeled. When a microsyringe needle was inserted into the ciliary body, the tracer diffused into the suprachoroid lamina and the intraocular ganglion cells, and a small number of labeled neurons appeared in the midplane between each side of the somatic oculomotor nuclei. After injection into the ACG, many labeled neurons were observed in the anteromedian nucleus, Edinger-Westphal nucleus, and midplane between the somatic oculomotor nuclei, their ventral continuations of the ventral tegmental area, and the periaqueductal gray. HRP/WGA-HRP injection into the CG labeled cells in all these areas and in the lateral border zones of the anteromedian, Edinger-Westphal and somatic oculomotor nuclei, and their ventral continuations of the ventral tegmental area. These findings indicate that the visceral oculomotor neurons which project to the ACG tend to be located more medially than those to the CG.     

The morphology of identified neurons in the abdominal ganglion of Aplysia californica

The morphology of identified neurons and of one multiaction interneuron (L10) of the abdominal ganglion of Aplysia has been studied using cobalt chloride, injected intracellularly. Cells with little synaptic input, R3-R14, had a relatively poorly developed dendritic tree, whereas the dendrite tree of cells L7 and L10, with extensive synaptic input, was highly complex. Cells L1-L6 and the RB cell cluster were found to have intermediate complexity of synaptic inputs and dendritic morphology. Within cell clusters, individual cells were often morphologically distinct. Identified cells have both invariant and variant axonal branches. Variant axons often project down other than their customary nerve trunks or are supernumerary. Three features of neuropil architecture were encountered. (1) When cells from the same cluster send their axons down the same nerve the axons often run in fascicles. (2) Although an identified cell's dendritic geometry varies from preparation to preparation, its dendrites always occupy approximately the same position in the neuropil. (3) The postsynaptic follower cells of L10 send their main axons through the axonal arborization of L10.     

Age-related changes in the lipid metabolism of Fisher 344 rats

Lipid metabolism of male Fisher 344 rats aged 2-24 months was studied. Serum and liver cholesterol levels did not display the age-related gradual increase seen in other rat strains. An increase in the serum plus liver cholesterol pool from 2 to 6 months was followed by a plateau through 18 months and then another increase at 24 months of age. The triglyceride pool increased from 2 to 6 months and then remained unchanged through 24 months of age. Cholesterol synthesis from acetate decreased 50% between 2 and 9 months and fell only slightly through 24 months of age. Assay of 3-hydroxy-3-methyl glutaryl Coenzyme A (HMG-CoA) reductase showed a similar pattern but did not decrease further after 9 months of age. Cholesterol 7alpha hydroxylase activity was not significantly altered by age. These age- and strain-related differences present an opportunity for a comparative study of the aging process using the parameters of lipid metabolism as indicators.     

Age-related changes in morphology and secretory responses of male rat lacrimal gland

This study investigates the differences in the outward appearance and morphology of lacrimal glands, the morphology within the lacrimal acinar cells and the secretion of protein from acinar cells of young (3-5 months) and aged (20 and 24 months) male rats. The appearance of the glands, as seen by the naked eye, differed between the three age-groups. The lacrimal gland of young animals was a smooth pink tissue, while the tissue from aged animals appeared lobular and white in colour, thought to result from infiltration of fatty/connective tissue. Glands from 24 month old animals had a more pronounced lobular appearance than the glands from 20 month old animals. Light microscopy studies revealed that as the animals aged there was evidence of progressive morphological changes. These changes included thickening of the connective tissue sheath, chronic inflammation with increased infiltration by mast cells, patchy destruction of ductal and vascular tissues, enlargement of lacrimal ducts, luminal swelling of the acini, and changes in acinar type. Electron microscopy (EM) studies revealed the presence of 3 types of acini in the rat lacrimal gland: acini which contained only protein secretory granules (serous acini), acini which contained protein and mucous secretory granules (seromucous acini), and acini which contained only mucous secretory granules (mucous acini). In young glands the majority of acini were serous with a few seromucous acini and even fewer mucous acini. In aged glands there were significant reductions in serous acini (ANOVA; P < 0.01) when compared to the young glands. In 20-month-old glands, there were marked increases in the percentage occurrence of seromucous acini, while in 24 month old glands, there were large increases in the relative number of mucous acini. Qualitative EM studies demonstrated that the typical acini from young glands contained numerous protein secretory granules. Ageing was associated with a progressive loss of protein (serous) secretory granules. Furthermore, marked changes and patchy destruction of the endoplasmic reticulum and Golgi apparatus were observed in acini of glands from aged rats when compared to acini of glands from young rats. Measurement of total protein output from acini revealed a significant (Student's t-test, P < 0.05) decrease in protein secretion from aged glands compared to glands from young animals. These results suggest that not only is there considerable structural damage, chronic inflammation and mast cell infiltration to the lacrimal gland with ageing, but also possible redifferentiation of acini from serous to seromucous and then to mucous acini. Furthermore, the results also suggest a reduction or an inability of the acini to synthesise and to secrete protein from glands of aged animals compared to glands of young rats. All of these changes appear to occur more rapidly as the rats mature between 20 and 24 months. These findings provide a morphological basis to explain the phenomenon of reduced tear/protein secretion with ageing.     

Age-related effects of nerve growth factor on the morphology of embryonic sensory neurons in vitro

Studies of neonatal and adult mammals have shown that neuronal morphology is regulated in part by the availability of target-derived neurotrophic factor. To test whether the same is true for embryonic neurons, which are dependent on target-derived neurotrophic factors for survival, we grew neural crest-derived sensory neurons from the trigeminal ganglion of avian embryos of different ages in vitro in different concentrations of nerve growth factor (NGF) and measured the number of branch points and total length of the resulting arborizations. Although the size and complexity of arborizations increased with embryonic age up to embryonic day (E)14, neuronal morphology for embryos younger than E14 was unaffected by the concentration of NGF in the culture medium. However, beginning at E14, the stage at which trigeminal neurons start to lose their absolute requirement for NGF for survival, the neurons had significantly more branch points and larger arborizations in higher concentrations of NGF. Thus, it appears that the extent of neurite outgrowth in young embryos is independent of neurotrophic factor concentration; each neuron that receives enough neurotrophic factor to survive elaborates approximately the same size arbor. As trigeminal neurons mature and become less dependent on neurotrophic factor for survival, they acquire the ability to respond to neurotrophic factor with increased neurite growth and branching, as in neonates and adults.     

Enhanced maternal aggression and associated changes in neuropeptide gene expression in multiparous rats.

Although it has often been speculated that prior reproductive experience improves subsequent maternal care, few studies have examined specific changes in behavior during a 1st versus 2nd lactation. During lactation, mothers display heightened aggression toward male intruders, purportedly to protect vulnerable young. In the current study, maternal aggression was examined in primiparous and age-matched multiparous females on postpartum days 5 (PPD5) and PPD15. Expression of oxytocin, oxytocin receptor, arginine vasopressin, arginine vasopressin V1a receptors, and corticotrophin-releasing hormone mRNA was measured following aggression testing at both time points using real-time quantitative PCR in brain regions previously implicated in the regulation of maternal aggression. Multiparity significantly enhanced maternal aggression on PPD5 but not on PPD15. In addition, this increased aggression was associated with region- and gene-specific changes in mRNA expression. These findings indicate that reproductive experience enhances maternal aggression, an effect that may be mediated by region-specific alterations in neuropeptidergic activity. The adaptations observed in multiparous females provide an innate model for the study of neuroplasticity in the regulation of aggression. (PsycINFO Database Record (c) 2010 APA, all rights reserved)     

Topographical organization of subicular neurons projecting to subcortical regions

Direct projections from the subiculum to the septum, thalamus, and hypothalamus were studied in the rat by the fluorescent retrograde double-labeling technique with Fast blue and Diamidino yellow. The results confirm and extend the previously reported findings. The dorsal subiculum projects primarily to the lateral septum, anterior and midline thalamus, and mammillary complex. The distribution areas of cell bodies of these projection neurons are substantially segregated, depending on their target region, and few single neurons project to two of the target regions by way of axon collaterals. The ventral subiculum projects mainly to the lateral septum, midline thalamus, and ventromedial hypothalamic area. The distribution areas of cell bodies of these projection neurons are considerably overlapped with one another, and a number of single neurons send axon collaterals to two of the lateral septum, midline thalamus, and ventromedial hypothalamic area. It is, thus, indicated that the populations of subicular neurons projecting to each of the subcortical structures examined are more distinctly segregated in the dorsal subiculum than in the ventral subiculum.     

Leptin activates hypothalamic CART neurons projecting to the spinal cord

Interviews were conducted with 265 orthopedic and chronic pain patients, using a structured diagnostic instrument (ADDIS/SUDDS) concerning their use of analgesics. Twenty-two percent of the patients met criteria for analgesic use disorders in accordance with DSM-III-R; 18.5% fulfilled DSM-IV criteria. Dextropropoxyphene was the most common analgesic prescribed and was used by 47% of the patients who met criteria for analgesic use disorders. It is concluded that patients with chronic pain using narcotic analgesics are at considerable risk of developing analgesic use disorders. Assessment of the use of analgesics should be offered to pain patients taking narcotic drugs.     

Identification of retinal ganglion cells projecting to the lateral hypothalamic area of the rat

Previous gain-of-function assays in Xenopus have demonstrated that Xwnt-3a can pattern neural tissue by reducing the expression of anterior neural genes, and elevating the expression of posterior neural genes. To date, no loss-of-function studies have been conducted in Xenopus to show a requirement of endogenous Wnt signaling for patterning of the neural ectoderm along the anteroposterior axis. We report that expression of a dominant negative Wnt in Xenopus embryos causes a reduction in the expression of posterior neural genes, and an elevation in the expression of anterior neural genes, thereby confirming the involvement of endogenous Wnt signaling in patterning the neural axis. We further demonstrate that the ability of Xwnt-3a to decrease expression of anterior neural genes in noggin-treated explants is dependent upon a functional FGF signaling pathway, while the elevation of expression of posterior neural genes does not require FGF signaling. The previously reported ability of FGF to elevate the expression of posterior neural genes in noggin-treated explants was found to be dependent on endogenous Wnt signaling. We conclude that neural induction occurs initially in a Wnt-independent manner, but that generation of complete anteroposterior neural pattern requires the cooperative actions of Wnt and FGF pathways.     

Age-related changes in gastric mucosal repair and proliferative activities in rats exposed acutely to aspirin

OBJECTIVES: (1) To determine whether and how outcome measurements in the ECASS trial are influenced by a shorter time window (0-3 vs. 3-6 h) between onset of symptoms and start of thrombolytic therapy using recombinant tissue plasminogen activator (rt-PA) in acute ischemic stroke. (2) To discuss the results of the ECASS 0- to 3-hour cohort with the results of the National Institute of Neurological Disorders and Stroke Study (NINDSS). DESIGN AND ANALYSIS: Analysis of the 0- to 3-hour and the 3- to 6-hour cohort in accordance with the ECASS protocol. Comparative analysis of the ECASS and NINDSS results following the NINDSS protocol using dichotomized endpoints. MAIN OUTCOME MEASURES: Primary endpoints: modified Rankin Scale, Barthel Index; secondary endpoints: combined Barthel/Rankin, long-term Scandinavian Stroke Scale, National Institutes of Health Stroke Scale, mortality at 30 and 90 days, occurrence of intracranial hemorrhage. NINDS trial endpoint: favorable outcome as defined in the NINDS trial. RESULTS: In ECASS, 87 patients were randomized within 3 h of stroke onset. Differences in favor of rt-PA treatment can be found for all primary and secondary outcome measures in the ECASS 0- to 3-hour cohort, except for mortality at day 30, which is somewhat higher in the rt-pA-treated group. However, due to the small sample size, the differences do not reach statistical significance. Early infarct signs (as defined by the ECASS protocol) are found as early as 2 h after stroke onset. Parenchymal hemorrhages are found significantly more often among rt-PA-treated patients. The results in the ECASS 0- to 3-hour cohort fit well with the results in NINDSS. CONCLUSION: Data from the 3-hour ECASS cohort support the efficacy of early thrombolytic therapy in acute hemispheric stroke patients. Comparing bleeding complications between the ECASS and NINDSS is difficult because of differences in the definition and occurrence of hemorrhagic events.     

Chronic morphine induces visible changes in the morphology of mesolimbic dopamine neurons

The mesolimbic dopamine system, which arises in the ventral tegmental area (VTA), is an important neural substrate for opiate reinforcement and addiction. Chronic exposure to opiates is known to produce biochemical adaptations in this brain region. We now show that these adaptations are associated with structural changes in VTA dopamine neurons. Individual VTA neurons in paraformaldehyde-fixed brain sections from control or morphine-treated rats were injected with the fluorescent dye Lucifer yellow. The identity of the injected cells as dopaminergic or nondopaminergic was determined by immunohistochemical labeling of the sections for tyrosine hydroxylase. Chronic morphine treatment resulted in a mean approximately 25% reduction in the area and perimeter of VTA dopamine neurons. This reduction in cell size was prevented by concomitant treatment of rats with naltrexone, an opioid receptor antagonist, as well as by intra-VTA infusion of brain-derived neurotrophic factor. In contrast, chronic morphine treatment did not alter the size of nondopaminergic neurons in the VTA, nor did it affect the total number of dopaminergic neurons in this brain region. The results of these studies provide direct evidence for structural alterations in VTA dopamine neurons as a consequence of chronic opiate exposure, which could contribute to changes in mesolimbic dopamine function associated with addiction.     

Localization of substance P and leucine enkephalin in the nerve terminals of the guinea pig paracervical ganglion

Immunoreactivities (IR) of substance P and leucine enkephalin have been demonstrated in the guinea-pig paracervical ganglion by an immunogold electron microscope method. Both substance P-IR and leucine enkephalin-IR were detected in large synaptic vesicles with electron-dense cores. The former neuropeptide was detected in nerve terminals and varicosities comprised mainly of large vesicles with electron-dense cores; the latter was detected in nerve terminals and varicosities that also included small, clear synaptic vesicles. In a minority of nerve terminals and varicosities coexistence of both immunoreactivities could be demonstrated within vesicles with an electron-dense core. Also present in these nerve terminals and varicosities were small, clear synaptic vesicles, though these were unreactive.     

Activation of neurons projecting to the paraventricular hypothalamic nucleus by intravenous lipopolysaccharide

The central nervous system interacts with the immune system to coordinate several components of the acute phase response, although the specific neuroanatomical pathways that mediate these responses are still uncharacterized. However, neurons in both the autonomic and endocrine components of the paraventricular hypothalamic nucleus (PVH) are characteristically activated in different models of immune stimulation. In the current study, we have used intravenous administration of lipopolysaccharide (LPS; 5 or 125 micrograms/kg) to induce the acute phase response. We subsequently coupled immunohistochemistry for Fos (as a marker of neuronal activation) with retrograde transport of the neuroanatomical tracer cholera toxin-b from the PVH. Several of the activated cell groups directly projected to the paraventricular nucleus, including the visceromotor (infralimbic) cortex, median preoptic nucleus, ventromedial preoptic area, bed nucleus of the stria terminalis, parabrachial nucleus, ventrolateral medulla, and nucleus of the solitary tract. These findings indicate that immune system stimulation activates cell groups from multiple nervous system levels that project to the paraventricular nucleus. We hypothesize that the activation of specific autonomic and endocrine elements of the PVH may be due to the activity of distinct afferents that converge on the PVH from multiple components of the central autonomic control system. Our results are consistent with the hypothesis that the PVH plays a key role in integrating diverse physiological cues into the varied manifestations that constitute the cerebral component of the acute phase response.     

Bilaterally projecting neurons in the two visual pathways of chicks

The influence of stereoscopic vision on the perception of optic flow fields was investigated in experiments based on a recently described illusion. In this illusion, subjects perceive a shift of the center of an expanding optic flow field when it is transparently superimposed by a unidirectional motion pattern. This illusory shift can be explained by the visual system taking the presented flow pattern as a certain self-motion flow field. Here we examined the dependence of the illusory transformation on differences in depth between the two superimposed motion patterns. Presenting them with different relative binocular disparities, we found a strong variation in the magnitude of the illusory shift. Especially when translation was in front of expansion, a highly significant decrease of the illusory shift occurred, down to 25% of its magnitude at zero disparity. These findings confirm the assumption that the motion pattern is interpreted as a self-motion flow field. In a further experiment we presented monocular depth cues by changing dot size and dot density. This caused a reduction of the illusory shift which is distinctly smaller than under stereoscopic presentation. We conclude that the illusory optic flow transformation is modified by depth information, especially by binocular disparity. The findings are linked to the phenomenon of induced motion and are related to neurophysiology.     

Dendritic morphology of presumptive vasoconstrictor and pilomotor neurons and their relations with neuropeptide-containing preganglionic fibres in lumbar sympathetic ganglia of guinea-pigs

We have used intracellular dye-filling combined with multiple-labelling immunofluorescence to examine the dendritic morphology of neurons and their relations with neuropeptide-containing preganglionic terminals in the lumbar sympathetic chain of guinea-pigs. Presumptive vasoconstrictor neurons with immunoreactivity for both tyrosine hydroxylase and neuropeptide Y dendritic fields that were significantly smaller, on average, than those of presumptive pilomotor neurons containing immunoreactivity to tyrosine hydroxylase but not to neuropeptide Y. However, there was considerable variation in the sizes of the dendritic fields of the vasoconstrictor neurons. Preganglionic nerve terminals containing immunoreactivity to calcitonin gene-related peptide, but not to substance P, only surrounded cell bodies of vasoconstrictor neurons containing immunoreactivity to tyrosine hydroxylase and neuropeptide Y. In most cases, the neuropeptide-containing preganglionic terminals were not associated closely with the distal dendrites of these neurons. Few neuropeptide-containing terminals were associated closely with either the cell bodies or dendrites of the pilomotor neurons. These results show that there is a considerable range in the size of dendritic trees of sympathetic final motor neurons. Some of this variation is related to the pathways within which the neurons lie, so that presumptive pilomotor neurons generally are larger than presumptive vasoconstrictor neurons. The marked variation in size of vasoconstrictor neurons raises the possibility that there may be a size dependent recruitment of these neurons, similar to that seen in pools of spinal motor neurons. The distribution of the peptide-containing preganglionic endings suggests that they would act predominantly at the cell body and proximal dendrites of the final motor neurons.