Teizo Ueyama

Central distribution of efferent and afferent components of the pudendal nerve in rat.

SummaryCentral distribution of efferent and afferent components of the pudendal nerve was examined in the rat by the horseradish peroxidase (HRP) method after HRP application to the central cut end of the pudendal nerve. The pudendal motoneurons were located in the dorsolateral, dorsomedial and lateral groups at L5 and L6. Each of the dorsolateral and dorsomedial groups constituted a slender longitudinal cell column. Pudendal motoneurons in the lateral group were scattered at L5, rostrodorsally to the dorsolateral group. The neurons in the dorsolateral and lateral groups were labelled with HRP applied to the nerve branch innervating the ischiocavernosus and sphincter urethrae muscles. The neurons in the dorsomedial group were labelled with HRP applied to the branch supplying the sphincter ani externus and bulbospongiosus muscles. Some dendrites of pudendal motoneurons in the dorsomedial group extended to the contralateral dorsomedial group. These crossing dendrites were observed not only in male rats but also in female. The average number of the pudendal motoneurons in the dorsolateral and dorsomedial groups were larger in male rats than in female. A few neurons of the intermediolateral nucleus at upper L6 were also labelled with HRP applied to the dorsalis penis (clitoridis) nerve. Axon terminals of the pudendal nerve were distributed, bilaterally with an ipsilateral predominance, to the gracile nucleus, as well as to the dorsal horn and dorsal commissural gray from L4 to S2. A few labelled axons were seen in the intermediolateral nucleus at L6 and S1. Axon terminals from the dorsalis penis nerve were distributed more medially in the dorsal horn than those from the perinealis nerve.

Distribution of nociceptin/orphanin FQ precursor protein and receptor in brain and spinal cord: A study using in situ hybridization and X-gal histochemistry in receptor-deficient mice

Nociceptin/orphanin FQ (N/OFQ) is an opioid‐like heptadecapeptide agonist for the opioid receptor homolog, N/OFQ receptor. To explore the precise distribution of the peptide‐receptor system, the authors examined the brain and spinal cord from receptor‐deficient mice bearing the targeted mutation (morcm1), a lacZ insertional mutation in the N/OFQ receptor gene. Precursor protein N/OFQ (preproN/OFQ) mRNA was detected by using in situ hybridization, and the N/OFQ receptor was detected by using X‐gal histochemistry. The N/OFQ receptor reflected by lacZ expression was observed at high levels in the dentate gyrus, lateral septum, subparafascicular thalamic nucleus, medial preoptic area, median preoptic nucleus, ventromedial preoptic nucleus, anterior hypothalamic area, paraventricular hypothalamic nucleus, ventromedial hypothalamic nucleus, auditory brainstem nuclei, pontine dorsal tegmentum, and nucleus of the solitary tract. In situ detection of the N/OFQ receptor mRNA by digoxigenin‐labeled riboprobes coupled with tyramide signal amplification in normal and wild‐type mice resulted in the regional distribution paralleling the lacZ expression in these regions. PreproN/OFQ mRNA was expressed at high levels in the subparafascicular thalamic nucleus, central gray, central tegmental field, auditory brainstem nuclei, caudal spinal trigeminal nucleus, and spinal dorsal horn. Furthermore, variable levels of expression of the peptide and receptor were seen in distinct sites of the brain and spinal cord. These data indicate a correspondence of the peptide and the receptor in local distribution at limbic, hypothalamic, and brainstem sites. Together with concurrent physiologic and behavioral studies in mutant mice, the results suggest functional roles for the N/OFQ system, including the central regulation of learning and memory, hearing ability, water balance, food intake, and blood pressure. J. Comp. Neurol. 424:489–508, 2000.

Identification of Rat Brainstem Sites with Neuronal Fos Protein Induced by Acoustic Stimulation with Pure Tones

Induction of Fos, a proto-oncogene c-fos protein product, was immunohistochemically examined in the rat brainstem by using pure tone stimuli (0.25 kHz, 4kHz and 8 kHz) at 60 and 80 dB sound pressure levels for 30 min. In comparison with non-stimulated control rats, the brainstem of sound-stimulated rats exhibited distinct Fos-labeled neuronal cell nuclei in i) the ascending auditory nuclei, ii) the brainstem sites which receive afferents from the auditory nuclei, i.e. the pretectum and rostroventrolateral reticular nucleus, iii) the parvocellular part of the ventral lateral geniculate nucleus, lateral reticular nucleus, ventral border region of the spinal trigeminal nucleus, and the medial vestibular and spinal vestibular nuclei, all of which lack established auditory projections, and iv) the brainstem sites where some Fos-labeled neurons were present in controls. Sound stimulation at 80 dB led to widespread Fos-labeling in all these sites. Sound stimulation at 60 dB caused a decrease in number of positive cells in the brainstem sites and yielded a tone-dependent subregional distribution pattern in the dorsal cochlear nucleus and central nucleus of the inferior colliculus.

Mapping of the cochlear nucleus subregions in the rat with neuronal Fos protein induced by acoustic stimulation with low tones

To explore the mode of appearance of Fos, a gene product of proto-oncogene c-fos, in the cochlear nucleus, a pure tone was given to rats and Fos was detected by immunohistochemistry. Following low-tone stimuli applied with moderate ranges of sound intensity, neurons with Fos-label occurred band-like in the ventral subregions of the dorsal cochlear nucleus. Organization of low-to-high tones in the ventral-to-dorsal orientation became visible at the caudal level. Several other subnuclei consistently exhibited Fos with no topographic pattern. Neurons interspersed in the adjoining vestibulocochlear nerve were also found to elicit Fos. Low-tone stimuli with very high sound intensity led to a rather widespread distribution of Fos, making the tone-specific distribution less visible.

Choline acetyltransferase immunoreactivity in the cat cerebellum.

Choline acetyltransferase immunoreactivity was demonstrated in particular projection systems in cat cerebellum by combining immunohistochemistry, retrograde tracing and lesioning paradigms. The monoclonal antibody used in this study recognized a 68,000 mol. wt protein on immunoblots of cat cerebellum and striatum. Choline acetyltransferase immunoreactivity was localized to some neurons and varicose fibers in the cerebellar nuclei, and also to some mossy fibers and endings (rosettes), fiber plexuses around Purkinje cells, granule cells and parallel fibers in the cerebellar cortex. In addition, the presence of choline acetyltransferase-immunoreactive large cells, presumptive Golgi cells, in the granular layer was confirmed. In each cerebellar nucleus, choline acetyltransferase-immunoreactive neurons contained either large, medium-sized or small cell bodies and were distributed evenly in the entire nuclear domain. Large and medium-sized ones were frequently encountered. Choline acetyltransferase-immunoreactive mossy fibers and rosettes were most abundant in the vermal lobules I-III, VIII, IX and the simple lobule, moderately accumulated in the vermal lobules IV-VII, X, crus I and crus II, and less abundant in the paramedian lobule, paraflocculus and flocculus. Some granule cells with prominent dendritic claws and bifurcating parallel axons were immunolabeled in the entire vermis with infrequent occurrence in the remaining cortices. Following unilateral lesioning of the cerebellar nuclei with electrocoagulation or kainate injections, a reduction in number of choline acetyltransferase-immunoreactive fibers occurred ipsilaterally in the cerebellar cortex and contralaterally in the red nucleus, ventrolateral thalamic nucleus and ventroanterior thalamic nucleus. In addition, perikarya of some cerebellothalamic neurons were shown to contain choline acetyltransferase immunoreactivity. The results indicate that some nucleocortical, cerebellorubral and cerebellothalamic projections are cholinergic and that a subpopulation of cholinergic granule cell-parallel fibers exists.

Distribution of neurons expressing α1G subunit mRNA of T-type voltage-dependent calcium channel in adult rat central nervous system

T-type voltage-dependent calcium channel has central roles in neuronal burst firing. The alpha1G subunit of T-type channel has been recently cloned and we here reported a cellular distribution of the alpha1G by in situ hybridization in adult rat brain and spinal cord. The cells expressing alpha1G were widely distributed in the central nervous system. The distribution seemed to be restricted to neurons, and exhibited a specific pattern in the cerebellum, thalamus, hippocampus and cerebral cortex.

Distribution and cerebellar projections of cholinergic and corticotropin-releasing factor-containing neurons in the caudal vestibular nuclear complex and adjacent brainstem structures

By using immunohistochemistry combined with lesioning and retrograde neuronal labeling techniques, cholinergic neurons and corticotropin-releasing factor-immunoreactive neurons were examined for their distribution, coincidence and cerebellar projections in feline vestibular nuclear complex and adjacent brainstem structures. Cholinergic neurons as revealed here with choline acetyltransferase immunoreactivity were found massively in the abducens and hypoglossal nuclei, dorsal motor nucleus of the vagus nerve and nucleus of Roller; less numerously in the medial vestibular, prepositus hypoglossi and solitary nuclei and the caudal two-thirds of descending vestibular nucleus; and only occasionally in the intercalated and supravestibular nuclei and cell groups f, x and z. Corticotropin-releasing factor-immunoreactive neurons were found clustered in the prepositus hypoglossi nucleus and also in cell groups f and x and the rostral two-thirds of descending vestibular nucleus, less numerously in the medial vestibular, intercalated and solitary nuclei and nucleus of Roller, and only occasionally in the caudal one-third of descending vestibular nucleus, the dorsal motor nucleus of the vagus nerve, supravestibular nucleus and cell group z. The lateral and superior vestibular nuclei did not contain either type of neuron. The two types of immunopositive neurons observed in most of the brainstem nuclei differed in cell size, distribution-pattern and rostrocaudal level of occurrence. While there were many regions which exhibited both types of immunopositive neurons, perikarya colocalizing the cholinergic and peptide markers were not detected in the brainstem. Following unilateral, partial lesioning of the vestibular nuclear complex, corticotropin-releasing factor-immunoreactive mossy fiber terminals (rosettes) disappeared from the ipsilateral flocculus. However, such lesions did not produce clear-cut changes of cholinergic terminals in the vermis. Following retrograde neuronal labeling combined with immunohistochemistry, the two types of immunopositive neurons observed in most of the brainstem sites were found to project to the vermal lobules I-III, IX and X. On comparison of these immunopositive projection neurons with non-immunoreactive, retrogradely labeled neurons, the cholinergic neurons and the peptide-immunoreactive neurons were found to constitute a major part of the total vestibulocerebellar neuronal population. The results indicate chemical heterogeneity in vestibular nuclear complex and cerebellar afferents.

Projections from the spinal cord to the cerebellar nuclei in the rabbit and rat

Abstract Fiber projections of the spinal cord to the cerebellar nuclei were investigated in rabbits and rats after hemisection of the cervical cord at various levels. Distribution of degenerating fibers and the field of termination were studied on sections stained with the Nauta and the Fink-Heimer methods. In rabbits a large number of degenerating fibers are seen bilaterally in the medial nuclei and the anterior and posterior interpositus nuclei throughout the rostrocaudal extent. The majority of them appear to terminate in the rostral portions rather than in the caudal portions of these nuclei. However, no convincing evidence is found as to the termination in the lateral nucleus. In rats, results are essentially similar in every respect. There is a dense projection in the medial nuclei of both sides throughout the rostrocaudal extent. Also a fair amount of projection is found in the interpositus nuclei of both sides, and further in the dorsomedial crest region and the dorsolateral “hump” region. No clear-cut termination is, however, seen in the lateral nucleus. These projection patterns are quite similar to those observed in the cat, and it is suggested that the spinal cord has an important relationship with the medial and the interpositus nuclei, but not with the lateral nucleus.

Contralateral termination of pudendal nerve fibers in the gracile nucleus of the rat

After applying horseradish peroxidase (HRP) unilaterally to central cut end of the pudendal nerve of the rat, transganglionic HRP-labeling of presumed axon terminals was constantly seen in the nucleus gracilis bilaterally with an ipsilateral predominance.

Odor exposure reveals non-uniform expression profiles of c-Jun protein in rat olfactory bulb neurons

In the main olfactory bulb, neurons are arranged strategically in distinct layers among which translaminar synaptic transmission can be made from the superficial, sensory to the deep, output layers that account for the processing of olfactory information. To search for stimulus-transcription coupling thought to be operated differentially in several cell types, c-Jun expression was examined immunohistochemically in rat olfactory bulb following 30-min odor stimulation with acetic acid and 1-butanol. c-Jun was rapidly induced in neuronal cell nuclei belonging to periglomerular, tufted, mitral and granule cells. The disappearance of c-Jun, however, differed between each cell type. In the glomerular layer, the glomeruli composed of c-Jun-expressing periglomerular cells were seen. Different odors led to labeling of different sets of glomeruli. The labeled periglomerular cells disappeared within 2 h. In all the deeper layers, however, a rather homogeneous label was noted for the tufted, mitral and granule cells present throughout the olfactory bulb, regardless of the difference in odor. In tufted and mitral cells, the c-Jun expression persisted for 4 days after odor stimulation. In the granule cell layer, numerous granule cells increased c-Jun immunoreactivity which lasted for 1 day following odor application. In control rats which were given clean air, the basal amount of c-Jun expression was seen confined to scattered granule cells. The results suggest that c-Jun is expressed in a variety of odorant-stimulated bulb neurons with a time course being dependent on cell type.