Search results for "Afferent"
showing 10 items of 115 documents
Motoneurons of the stapedius muscle in the guinea pig middle ear: Afferent and efferent transmitters
2008
The objective of the present study was to identify efferent and afferent transmitters of motoneurons of the stapedius muscle of the middle ear in order to gain more insight into the neuronal regulation of the muscle. To identify motoneurons, we injected the fluorescent neuronal tracer Fluorogold (FG) into the muscle after preparation of the middle ear in adult guinea pigs. Upon terminal uptake and retrograde neuronal transport, we observed FG in neurons located medial and ventral to the nucleus of the facial nerve ipsilateral to the injection site. Immunohistochemical studies of these motoneurons showed that the majority contains calcitonin gene-related peptide. Our data further demonstrate…
Vomeronasal inputs to the rodent ventral striatum.
2008
Vertebrates sense chemical signals through the olfactory and vomeronasal systems. In squamate reptiles, which possess the largest vomeronasal system of all vertebrates, the accessory olfactory bulb projects to the nucleus sphericus, which in turn projects to a portion of the ventral striatum known as olfactostriatum. Characteristically, the olfactostriatum is innervated by neuropeptide Y, tyrosine hydroxylase and serotonin immunoreactive fibers. In this study, the possibility that a structure similar to the reptilian olfactostriatum might be present in the mammalian brain has been investigated. Injections of dextran-amines have been aimed at the posteromedial cortical amygdaloid nucleus (th…
Nitric oxide synthase-immunoreactive vagal afferent fibers in rat superior cervical ganglia
1995
Abstract Chronic (5–14 days) preganglionic denervation of the rat superior cervical ganglia by sectioning the cervical sympathetic trunk resulted in a time-related partial or complete loss of nitric oxide synthase (isoform I)-immunoreactive fibers and terminals surrounding many sympathetic ganglionic neurons. Unexpectedly, denervation unmasked many varicose nitric oxide synthase-immunoreactive fibers, some of which could be traced the entire length of the superior cervical ganglia. Injection of the retrograde tracer Fluorogold into the superior cervical ganglia labeled a population of nodose ganglion cells and of dorsal root ganglion cells from C8 to T3 segments. When the same sections were…
Convergence of olfactory and vomeronasal projections in the rat basal telencephalon
2007
Olfactory and vomeronasal projections have been traditionally viewed as terminating in contiguous non-overlapping areas of the basal telencephalon. Original reports, however, described areas such as the anterior medial amygdala where both chemosensory afferents appeared to overlap. We addressed this issue by injecting dextran amines in the main or accessory olfactory bulbs of rats and the results were analyzed with light and electron microscopes. Simultaneous injections of different fluorescent dextran amines in the main and accessory olfactory bulbs were performed and the results were analyzed using confocal microscopy. Similar experiments with dextran amines in the olfactory bulbs plus Fl…
Central alterations of neuromuscular function and feedback from group III-IV muscle afferents following exhaustive high-intensity one-leg dynamic exe…
2015
The aims of this investigation were to describe the central alterations of neuromuscular function induced by exhaustive high-intensity one-leg dynamic exercise (OLDE, study 1) and to indirectly quantify feedback from group III-IV muscle afferents via muscle occlusion (MO, study 2) in healthy adult male humans. We hypothesized that these central alterations and their recovery are associated with changes in afferent feedback. Both studies consisted of two time-to-exhaustion tests at 85% peak power output. In study 1, voluntary activation level (VAL), M-wave, cervicomedullary motor evoked potential (CMEP), motor evoked potential (MEP), and MEP cortical silent period (CSP) of the knee extensor…
Direct projections to the rat pineal gland via the stria medullaris thalami. An anterograde tracing study by use of horseradish peroxidase.
1986
The possible presence of a direct nervous projection from the paraventricular nucleus (PVN) of the hypothalamus to the pineal gland of the rat was investigated by means of the anterograde neuron-tracing method using horseradish peroxidase. The tracer was injected unilaterally into the PVN and the animals were allowed to survive between 12 and 26 h. Numerous peroxidase-positive fibers were observed, ipsilateral to the injection site, in the stria medullaris thalami and could be followed into the medial habenular nucleus and the habenular commissure. From there, fibers penetrated into the deep pineal gland (lamina intercalaris), and further into the pineal stalk. These data support results of…
Regulation of noradrenergic coerulean neuronal firing mediated by 5-HT2 receptors: involvement of the prepositus hypoglossal nucleus.
1991
Abstract Previous studies have indicated a 5-HT2-mediated inhibitory influence on unit activity in the locus coeruleus. In the present work, attempts were made to determine which area(s) of the brain is (are) involved in this effect: (1) Microiontophoretic application of serotoninergic compounds (quipazine, ketanserin, RU 24969 (Roussel Uclaf), 8-hydroxy-2(di-n-propylamino) tetralin (8-OH-DPAT), metergoline, serotonin) in the locus coeruleus, did not alter the coerulean discharge. Local microinjection of quipazine or ketanserin in the area of the locus coeruleus, as well as in one of its major afferents, the prepositus hypoglossi, had no effect on the unit activity in the locus coeruleus. 1…
Immunohistochemical analysis of chromogranin A and multiple peptides in the mammalian Merkel cell: further evidence for its paraneuronal function?
1989
By the use of light microscopic immunohistochemistry, epidermal Merkel cells have been examined for the coexistence of some neuropeptides and chromogranin A (CGA). Peptide and CGA-immunophenotypes were similar in adult Merkel cells but variable in fetal skin, where CGA preceded the expression of peptides which were partly expressed only in a subpopulation of Merkel cells from hair follicles. Thus, only Substance P (SP) and calcitonin gene-related peptide (CGRP) were expressed in a subpopulation of Merkel cells from hair follicles. There were similar Merkel cell densities visualized on consecutive paraffin sections by the use of antisera against peptides, CGA and cytokeratin offering useful …
A nitrergic projection from the superior olivary complex to the inferior colliculus of the rat
2003
The present study was conducted to test whether the ascending auditory projection from the superior olivary complex (SOC) of the brainstem to the inferior colliculus (IC) may use nitric oxide (NO) as a neuroactive compound. We identified olivo-collicular projection neurons in subnuclei of the SOC by retrograde neuronal tracing with Fluoro-Gold (FG) injected into the central nucleus of the IC. Sections containing retrograde labelled neurons were subjected to immunohistochemical incubation in an antiserum directed against the enzyme responsible for NO production in nerve cells, neuronal NO synthase (nNOS). The analysis showed that FG-containing neurons as well as nNOS-immunoreactive neurons w…
Demonstration of retinal afferents in the RCS rat, with reference to the retinohypothalamic projection and suprachiasmatic nucleus.
1995
In the Royal College of Surgeons (RCS) rat, characterized by inherited retinal dystrophy, retinal projections to the brain were studied using anterograde neuronal transport of cholera toxin B subunit upon injection into one eye. The respective immunoreactivity was found predominantly contralateral to the injection site in the lateral geniculate nucleus, superior colliculus, nucleus of the optic tract, medial terminal nucleus of the accessory optic tract, and bilateral hypothalamic suprachiasmatic nuclei. Although terminal density was somewhat reduced in dystrophic rats, the projection patterns in these animals appeared similar to those seen in their congenic controls and were comparable to …