NADPH-diaphorase-positive nerve fibers associated with motor endplates in the rat esophagus: new evidence for co-innervation of striated muscle by enteric neurons.

NADPH-diaphorase histochemistry was combined with demonstration of acetylcholinesterase and immunocytochemistry for calcitonin gene-related peptide to study esophageal innervation in the rat. Most of the myenteric neurons stained positively for NADPH-diaphorase, as did numerous varicose nerve fibers in the myenteric plexus, among striated muscle fibers, around arterial blood vessels, and in the muscularis mucosae. A majority of motor endplates (as demonstrated by acetylcholinesterase histochemistry or calcitonin gene-related peptide immunocytochemistry) were associated with fine varicose NADPH-diaphorase-positive nerve fibers.

Visualization of human choroidal ganglion cells with the supravital fluorescent dye 4-(4-diethylaminostyryl)-N-methylpyridium iodide.

The distribution and morphology of ganglion cell bodies and nerve fibers in supravital human choroidea is studied by staining with the fluorescent dye 4-(4-diethylaminostyryl)-N-methylpyridium iodide (4-Di-2-ASP). We have used the choroids from human donor eyes donated for cornea transplantation. The isolated tissues were rinsed in ringer solution and processed within up to 24 h after death with 3 microM of 4-Di-2-ASP in Ringer for 5-60 min at different temperatures (4-37 degrees C).

Vagal innervation of the rat pylorus: an anterograde tracing study using carbocyanine dyes and laser scanning confocal microscopy.

In an attempt to identify the distribution and structure of vagal fibers and terminals in the gastroduodenal junction, vagal efferents were labeled in vivo by multiple injections of the fluorescent carbocyanine dye DiA into the dorsal motor nucleus (dmnX), and vagal afferents were anterogradely labeled by injections of DiI into the nodose ganglia of the same or separate rats. Thick frontal cryostat sections were analysed either with conventional or laser scanning confocal microscopy, using appropriate filter combinations and/or different wavelength laser excitation to distinguish the fluorescent tracers. Vagal efferent terminal-like structures were present in small ganglia within the circular sphincter muscle, which, in the absence of a well-developed, true myenteric plexus at this level, represent the myenteric ganglia.

Rectospinal neurons: cell bodies, pathways, immunocytochemistry and ultrastructure.

A novel class of enteric neurons projecting directly from the rectal wall to the spinal cord, "rectospinal neurons", was investigated in rats by combined retrograde neuronal tracing, immunocytochemistry and electron microscopy. Rectospinal neurons were almost confined to myenteric ganglia of the distal rectum below the pelvic diaphragm and were labeled preferentially by injections into spinal cord segments L6/S1. Injections into more rostral spinal cord segments resulted in hardly any labeled enteric neurons.

Tyrosine-hydroxylase-containing vagal afferent neurons in the rat nodose ganglion are independent from neuropeptide-Y-containing populations and project to esophagus and stomach.

Immunoreactivity to the rate limiting enzyme of catecholamine synthesis, tyrosine hydroxylase, has been described in the inferior sensory (= nodose) ganglion of the vagal nerve in the rat. The aim of the present study was to characterize further this neuronal population. The neurons do not represent displaced autonomic efferent neurons, since they do not receive synaptic input, as indicated by the absence of synaptophysin-immunoreactive terminals.

An anterograde tracing study of the vagal innervation of rat liver, portal vein and biliary system.

In order to investigate the distribution and structure of the vagal liver innervation, abdominal vagal afferents and efferents were selectively labeled by injecting WGA-HRP or Dil into the nodose ganglia, and DiA into the dorsal motor nucleus, respectively. Vagal afferent fibers produced characteristic terminal-like structures at three locations in the liver hilus: 1. Fine varicose endings preferentially surrounding, but not entering, the numerous peribiliary glands in the larger intra and extrahepatic bile ducts 2.

A direct projection from the medial vestibular nucleus to the cervical spinal dorsal horn of the rat, as demonstrated by anterograde and retrograde tracing.

Phaseolus vulgaris leucoagglutinin and wheat germ agglutinin-horseradish peroxidase were iontophoretically injected into different parts of the vestibular nuclear complex (VNC) of the rat. Injections centered into the caudal part of the medial vestibular nucleus revealed a vestibulospinal projection predominantly to the dorsal horn of the cervical spinal cord, besides the expected projection to the intermediate zone (IZ) and ventral horn (VH). While most of the anterogradely labelled fibres could be localized in laminae III to V, some scattered fibres were also seen in laminae I and VI.

A cervical primary afferent input to vestibular nuclei as demonstrated by retrograde transport of wheat germ agglutinin-horseradish peroxidase in the rat.

Wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) was microiontophoretically injected into the vestibular nuclear complex of the rat. Retrogradely labeled neurons were found in ipsilateral spinal ganglia C2-C3 only if the injection site was in the caudal part of the medial vestibular nucleus (MVN). Injections into rostral parts of the MVN, the superior, lateral and descending vestibular nuclei (SVN, LVN, DVN), the nucleus of the solitary tract (STN) and the reticular formation did not result in spinal ganglion labeling.

Vagal afferent fibers almost exclusively innervate islets in the rat pancreas as demonstrated by anterograde tracing.

Anterograde tracing from the nodose ganglion with wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) was utilized to investigate vagal afferent innervation of the rat pancreas. Labelled afferent fibers were consistently detected in islets in all animals. Only about 10% of islets were labelled even in best cases.

Vagal paraganglia of the rat.

Paraganglia are associated with every branch of the rat vagus nerve except the pharyngeal branch. Some of the paraganglia closely resemble the glomus caroticum, whereas others appear like small, intensely fluorescent (SIF) cells of autonomic ganglia. The paraganglionic cells of SIF cell-like bodies (SLB) store catecholamines (the most abundant is probably noradrenaline) and in some cases neurotensin.

Central distribution of cervical primary afferents in the rat, with emphasis on proprioceptive projections to vestibular, perihypoglossal, and upper thoracic spinal nuclei.

The projections of primary afferents from rostral cervical segments to the brainstem and the spinal cord of the rat were investigated by using anterograde and transganglionic transport techniques. Projections from whole spinal ganglia were compared with those from single nerves carrying only exteroceptive or proprioceptive fibers. Injections of horseradish peroxidase (HRP) or wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) were performed into dorsal root ganglia C2, C3, and C4.

Rectospinal neurons: evidence for a direct projection from the enteric to the central nervous system in the rat.

Wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP), horseradish peroxidase (HRP), and Fluorogold injections were made into the spinal cord segments L4-S2, and HRP was applied to cut L6 and S1 dorsal roots in the rat. These procedures resulted in retrograde labeling of neuronal cell bodies in the rectal wall. Labeled neurons were found both inside and outside myenteric ganglia.

The distribution of anterogradely labeled I--IV primary afferents in histochemically defined compartments of the rat's sternomastoid muscle.

The sternomastoid muscle of the rat is divided into a white (dominated by fast-glycolytic twitch fibers) and a red (dominated by fast oxidative-glycolytic twitch fibers, but also containing slow-oxidative twitch fibers) compartment. Previous reports on exclusive location of muscle spindles in the red portion were confirmed. On the basis of anterograde labeling with horseradish peroxidase-wheat germ agglutinine conjugate (WGA-HRP) it was shown in this study that, in addition to muscle spindle compartmentalisation, there was also an exclusive occurrence of tendon organs in the red part of the muscle; moreover, fine afferents (III- and IV-afferents) were mainly distributed to this portion as well.

Sensory vagal innervation of the rat esophagus and cardia: a light and electron microscopic anterograde tracing study.

Wheat germ agglutinin-horseradish peroxidase conjugate (WGA-HRP) was injected into nodose ganglia of rats. In the esophagus and cardia, dense networks of anterogradely labeled fibers and beaded terminal-like arborisations were observed around myenteric ganglia after combined histochemistry for HRP and acetylcholinesterase. The muscularis externa and interna proper were free of label except for a few traversing fibers.

Vagal primary afferent terminals in the dorsal motor nucleus of the rat: are they making monosynaptic contacts on preganglionic efferent neurons?

After horseradish peroxidase (HRP) application to the cut cervical vagus nerve in rats, labelled primary afferent terminals could be demonstrated in the dorsal motor nucleus at the ultrastructural level by a combined glucose oxidase-silver-gold intensification technique. Some labelled boutons contacted labelled dendrites of preganglionic neurons. Thus, the occurrence of a few monosynaptic primary afferent-preganglionic efferent contacts in the dorsal motor nucleus could be demonstrated.

The central projections of primary afferent neurons of greater splanchnic and intercostal nerves in the rat. A horseradish peroxidase study.

The central projections of primary afferent fibers of the greater splanchnic nerve of the rat were investigated using the transganglionic horseradish peroxidase transport technique. In addition, the corresponding spinal ganglion cells and the preganglionic sympathetic neurons were demonstrated. For comparing visceral and somatic afferents, intercostal nerve afferents were labelled by the same technique.

Differential labeling by horseradish peroxidase of small and large spinal neurons of rats.

Solid horseradish peroxidase (HRP) was applied to the crushed peroneal nerves of rats and its retrograde transport to spinal ganglion cells and spinal motoneurons was examined after varying survival times. Following short (22-39 h) survival times predominantly small sensory and motoneuronal cell bodies contained HRP. Following long intervals (72-96 h), the percentage of labeled large cells increased in both groups of neurons.

Dynamics of the transganglionic movement of horseradish peroxidase in primary sensory neurons.

The dynamics of horseradish peroxidase (HRP) transport in primary sensory neurons were studied in rats by demonstration of the reaction product in spinal nerves, spinal ganglia, dorsal roots and in the spinal cord at different survival times after applcation of the enzyme to the transected sciatic nerve and to the spinal cord. Using tetramethylbenzidine as the chromogen according to Mesulam (1978), transganglionic transport of HRP was shown in both the disto-proximal direction after peripheral application, and proximo-distal direction after central application. Significant differences in staining intensity between the central and peripheral processes of primary sensory neurons were found after all survival times used in this study.

The ansa cervicalis and the infrahyoid muscles of the rat. II. Motor and sensory neurons.

Perikarya of motoneurons and spinal ganglion cells attributed to infrahyoid muscle nerves of the rat were labelled by retrogradely transported horseradish peroxidase (HRP). For the differentiation of motor and sensory axons cross sections of the nerves were stained for acetylcholinesterase. Numbers and diameter distributions of perikarya and myelinated axons were determined.

Afferent neurons of the hypoglossal nerve of the rat as demonstrated by horseradish peroxidase tracing.

Cell bodies of sensory neurons of the rat's hypoglossal nerve were demonstrated by the somatopetal horseradish peroxidase (HRP) transport technique. Labelled perikarya were found within the second and third cervical spinal ganglia and in the vagal sensory ganglia. After application of HRP to the cut peripheral trunk of the hypoglossal nerve about 200 labelled cell bodies were counted in each animal.