Cuneate nucleus

About: Cuneate nucleus is a research topic. Over the lifetime, 614 publications have been published within this topic receiving 24859 citations. The topic is also known as: cuneate nucleus of spinal cord.

Central distribution of efferent and afferent components of the cervical branches of the vagus nerve. A HRP study in the cat.

Abstract: Central distribution of efferent and afferent components of the cervical branches of the vagus nerve in the cat was studied by applying horseradish peroxidase (HRP) to the superior laryngeal nerve (SLN), pharyngeal branch (PhB), recurrent laryngeal nerve (RLN) or middle portion of the cervical trunk of the vagus nerve (CTV). After applying HRP to the SLN, PhB or RLN, labeled neurons were mainly seen ipsilaterally in the ambiguus nuclear complex (Amb) at levels of the rostral, middle, or caudal portions of the Amb, respectively. After application of HRP to the CTV, labeled neurons were distributed ipsilaterally throughout the Amb. Neurons in the lateral reticular formation medial to the spinal trigeminal nucleus were also labeled ipsilaterally with HRP from the SLN or CTV; these neurons appeared to be the caudal extension of the inferior salivatory nucleus. Neurons within the dorsal motor nucleus of the vagus nerve (DMV) were labeled ipsilaterally only after HRP application to the CTV. The axons of neurons in the rostral Amb and the lateral reticular formation, labeled retrogradely from the SLN or CTV, ran dorsomedially to form a genu in the dorsomedial tegmental region near the floor of the fourth ventricle, and then turned and left ventrolaterally from the medulla oblongata. On the other hand, axons of neurons in the caudal two-thirds of the Amb, labeled retrogradely from the PhB, RLN or CTV, ran dorsomedially to a region ventral to the DMV, where they turned ventrolaterally to form loops before leaving the brainstem. A few axons of neurons in the rostralmost regions of the DMV were also found to form a genu near the floor of the fourth ventricle before running ventrolaterally to leave the brianstem. Axon terminals in the solitary nucleus (Sn) were transganglionically labeled most densely in the medial and interstitial subnuclei from the SLN, in the medial and dorsolateral subnuclei from the RLN, and in the medial and gelatinous subnuclei from the CTV. Application of HRP to the SLN also revealed labeling of axon terminals in the principal sensory and spinal trigeminal nuclei, the medial cuneate nucleus and the dorsal horn of the C1 and C2 cord segments.

Comparative study on the distribution patterns of P2X1–P2X6 receptor immunoreactivity in the brainstem of the rat and the common marmoset (Callithrix jacchus): Association with catecholamine cell groups

Abstract: The present study investigated the topographical distribution of P2X(1)-P2X(6) receptor subtypes in the rat and common marmoset hindbrain by immunohistochemistry. In addition, double-labeling immunofluorescence was used to determine the extent of colocalization between catecholamine cell groups and the various P2X receptors. The data demonstrate a widespread distribution pattern for all six P2X receptors throughout both the rat hindbrain and the marmoset hindbrain, although distinctions between species, brain nuclei, and P2X receptor subtypes exist. In rat, dense staining for the P2X receptors was found in the nucleus of the solitary tract (NTS), medial vestibular nucleus, and medial and lateral parabrachial nuclei. Moderate staining was observed in the hypoglossal nucleus, cuneate nucleus, inferior olive, prepositus hypoglossi, rostral ventrolateral medulla (RVLM), and locus coeruleus. Staining was also observed in the gracile nucleus, the mesencephalic trigeminal nucleus, and the central pontine gray. In marmoset, prominent P2X receptor-like immunoreactivity occurred in the NTS, medial cuneate nucleus, prepositus hypoglossi, and medial vestibular nucleus. Moderate staining was observed in the area postrema, dorsal motor nucleus of the vagus, lateral cuneate, lateral reticular, spinal trigeminal nucleus, RVLM, and inferior olive. Immunofluorescent double labeling of tyrosine hydroxylase (TH)-containing cells revealed that all subtypes of P2X receptors show some degree of colocalization with TH. The highest proportion of TH and P2X receptor double labeling was in the A5 region (with the P2X(2) subunit), whereas the lowest proportion of double-labeled cells occurred in the C2 region of the NTS for the P2X(5) subunit. These findings support a role for extracellular adenosine 5'-triphosphate in fast synaptic neurotransmission within the brainstem.

The central projection of muscle afferent fibres to the lower medulla and upper spinal cord: An anatomical study in the cat with the transganglionic transport method

Abstract: The projection of muscle afferent fibres to the medulla oblongata and upper spinal cord was studied in the cat by using transganglionic transport of wheat germ agglutinin-horseradish peroxidase conjugate. The results demonstrate a precise, musculotopic termination pattern in the external cuneate nucleus; thus, fibres from the intrinsic muscles of the paw terminate medially; those from forearm, arm, and shoulder muscles terminate progressively more laterally; and those from neck and thoracic muscles terminate in the ventrolateral and dorsolateral parts, respectively. Muscle afferent fibres to the main cuneate nucleus terminate in the ventral "reticular" region of the nucleus, with a sparse projection also to the ventral part of the rostral and caudal regions, including the base of the dorsal horn. Fibres from the neck muscles terminate slightly more laterally in the ventral region than do those from the limb muscles, but otherwise, and thus contrary to the case in the external cuneate nucleus, no topographic organization was detected. In the spinal cord, projection was found to laminae I and V, and from the musculature of the back of the neck to the central cervical nucleus.