Spinal serotonin is derived entirely from bulbar sources and plays an important role in spinal modulatory processes, including pain modulation. Establishing the electrophysiological properties of SEROTONERGIC bulbospinal neurons in the pontomedullary raphe and reticular formation is critical to understanding the physiological role of serotonin in the spinal cord. Neurons were characterized by t...

with the property that for any pair r, s of elements of R either r = s or there is very little free cancellation in forming the product rs. The classical example of such a group is the fundamental group of a closed orientable 2-manifold of genus k. The study of this group has given rise both to the theory of one-relator groups, initiated by Magnus ([3]), and to the theory of small cancellation ...

The 5,6-dihydroxytryptamine administration into the median raphe nucleus in the cat resulted in an increase in the carbachol-induced emotional-defensive behavior and a decrease of 5-hydroxyindoleacetic acid and dopamine level in the hypothalamus, midbrain and amygdala. Lesions of median raphe nucleus resulted in similar, but more subtle alterations of post-carbachol emotional-defensive response...

The distribution of Met-enkephalin- and substance P-immunoreactive neurons was studied by indirect immunofluorescence in some areas related to pain and analgesia. Met-enkephalin- and substance P-positive cell bodies and nerve terminals were observed in the periaqueductal central gray, the nucleus raphe magnus, the marginal layers and substantia gelatinosa of the spinal trigeminal nucleus, and t...

Sympathetic premotor neurons directly control sympathetic preganglionic neurons (SPNs) in the intermediolateral cell column (IML) of the thoracic spinal cord, and many of these premotor neurons are localized in the medulla oblongata. The rostral ventrolateral medulla contains premotor neurons controlling the cardiovascular conditions, whereas rostral medullary raphe regions are a candidate sour...

Cells within the ventral medulla whose axons descend to the spinal dorsal horn via the dorsolateral funiculus (DLF) play an important role in pain modulation. Previous evidence suggests that this pathway is primarily serotonergic. We have examined this hypothesis directly using combined retrograde horseradish peroxidase/serotonin immunohistochemical staining. Cells of the ventral medulla contri...

Pain is an unpleasant experience which results from both physical and psychological responses to injury. A complex set of pathways transmits pain messages from the periphery to the central nervous system, where control occurs from higher centres. Primary afferent pain fibres synapse with second-order neurons in the dorsal horn of the spinal cord. Ascending spinothalamic and spinoreticular tract...