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...

Introduction: The antinociceptive effect of morphine is, in part, mediated through the activation of a descending pathway. One of the major components of this pathway is the nucleus raphe magnus (NRM). Our previous study demonstrated the involvement of NRM in the analgesic effect of morphine microinjected into the nucleus cuneiformis (NCF) in a descending manner. The aim of the current study...

Selective retrograde labelling was used as an autoradiographic method to identify possible excitatory amino acid afferents to nucleus raphe magnus (NRM). Injections of 25-50 nl 10(-2) or 10(-3) M D-[3H]aspartate into the NRM resulted in prominent labelling of cells in ventrolateral mesencephalic periaqueductal gray (PAG). Electrophysiologically, stimulation in ventrolateral PAG excited cells in...

Currently, opioid-based drugs are the most effective pain relievers that are widely used in the treatment of pain. However, the analgesic efficacy of opioids is significantly limited by the development of tolerance after repeated opioid administration. Glutamate receptors have been reported to critically participate in the development and maintenance of opioid tolerance, but the underlying mech...

Hyperexcitable reflex blinks are a cardinal sign of Parkinson's disease. The first step in the circuit linking the basal ganglia and brainstem reflex blink circuits is the inhibitory nigrostriatal pathway (Basso et al., 1996). The current study reports the circuits linking the superior colliculus (SC) to trigeminal reflex blink circuits. Microstimulation of the deep layers of the SC suppresses ...

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 effects of somatostatin (SOM) after intravenous application and intracerebral microinjection into the medullary nucleus raphe magnus (NRM) or into the periaqueductal gray (PAG) on the spinal nociceptive transmission was quantitatively studied in the anesthetized cat. Noxious heat-evoked responses of multireceptive lumbar spinal dorsal horn neurons were reversibly depressed to 56.6 +/- 9.7% ...

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...