scholarly journals Stimulation of the raphe nuclei produces EEG spikes in the hippocampus of the normal rabbit.

1984 ◽  
Vol 51 (5) ◽  
pp. 557-567
Author(s):  
Shiro Minami
Keyword(s):  
Raphe Nuclei ◽  
Raphé Nuclei ◽  
Stimulation Of

scholarly journals Quipazine Elicits Swallowing in the Arterially Perfused Rat Preparation: A Role for Medullary Raphe Nuclei?

2020 ◽  
Vol 21 (14) ◽  
pp. 5120
Author(s):  
Victor Bergé-Laval ◽  
Christian Gestreau
Keyword(s):  
Therapeutic Option ◽  
Experimental Studies ◽  
Raphe Nuclei ◽  
Excitatory Effect ◽  
Motor Patterns ◽  
Systemic Injection ◽  
Medullary Raphe ◽  
Raphé Nuclei ◽  
Stimulation Of

Pharmacological neuromodulation of swallowing may represent a promising therapeutic option to treat dysphagia. Previous studies suggested a serotonergic control of swallowing, but mechanisms remain poorly understood. Here, we investigated the effects of the serotonergic agonist quipazine on swallowing, using the arterially perfused working heart-brainstem (in situ) preparation in rats. Systemic injection of quipazine produced single swallows with motor patterns and swallow-breathing coordination similar to spontaneous swallows, and increased swallow rate with moderate changes in cardiorespiratory functions. Methysergide, a 5-HT2 receptor antagonist, blocked the excitatory effect of quipazine on swallowing, but had no effect on spontaneous swallow rate. Microinjections of quipazine in the nucleus of the solitary tract were without effect. In contrast, similar injections in caudal medullary raphe nuclei increased swallow rate without changes in cardiorespiratory parameters. Thus, quipazine may exert an excitatory effect on raphe neurons via stimulation of 5-HT2A receptors, leading to increased excitability of the swallowing network. In conclusion, we suggest that pharmacological stimulation of swallowing by quipazine in situ represents a valuable model for experimental studies. This work paves the way for future investigations on brainstem serotonergic modulation, and further identification of neural populations and mechanisms involved in swallowing and/or swallow-breathing interaction.

scholarly journals Medullary raphe nuclei activate the lumbosacral defecation center through the descending serotonergic pathway to regulate colorectal motility in rats

2018 ◽  
Vol 314 (3) ◽  
pp. G341-G348 ◽  
Author(s):  
Hiroyuki Nakamori ◽  
Kiyotada Naitou ◽  
Yuuki Horii ◽  
Hiroki Shimaoka ◽  
Kazuhiro Horii ◽  
...  
Keyword(s):  
Spinal Cord ◽  
Electrical Stimulation ◽  
Raphe Nuclei ◽  
Lumbosacral Spinal Cord ◽  
Pelvic Nerves ◽  
Medullary Raphe ◽  
Raphé Nuclei ◽  
Type 3 ◽  
Stimulation Of

Colorectal motility is regulated by two defecation centers located in the brain and spinal cord. In previous studies, we have shown that administration of serotonin (5-HT) in the lumbosacral spinal cord causes enhancement of colorectal motility. Because spinal 5-HT is derived from neurons of the medullary raphe nuclei, including the raphe magnus, raphe obscurus, and raphe pallidus, we examined whether stimulation of the medullary raphe nuclei enhances colorectal motility via the lumbosacral defecation center. Colorectal pressure was recorded with a balloon in vivo in anesthetized rats. Electrical stimulation of the medullary raphe nuclei failed to enhance colorectal motility. Because GABAergic neurons can be simultaneously activated by the raphe stimulation and released GABA masks accelerating actions of the raphe nuclei on the lumbosacral defecation center, a GABAA receptor antagonist was preinjected intrathecally to manifest excitatory responses. When spinal GABAA receptors were blocked by the antagonist, electrical stimulation of the medullary raphe nuclei increased colorectal contractions. This effect of the raphe nuclei was inhibited by intrathecal injection of 5-hydroxytryptamine type 2 (5-HT2) and type 3 (5-HT3) receptor antagonists. In addition, injection of a selective 5-HT reuptake inhibitor in the lumbosacral spinal cord augmented the raphe stimulation-induced enhancement of colorectal motility. Transection of the pelvic nerves, but not transection of the colonic nerves, prevented the effect of the raphe nuclei on colorectal motility. These results demonstrate that activation of the medullary raphe nuclei causes augmented contractions of the colorectum via 5-HT2 and 5-HT3 receptors in the lumbosacral defecation center. NEW & NOTEWORTHY We have shown that electrical stimulation of the medullary raphe nuclei causes augmented contractions of the colorectum via pelvic nerves in rats. The effect of the medullary raphe nuclei on colorectal motility is exerted through activation of 5-hydroxytryptamine type 2 and type 3 receptors in the lumbosacral defecation center. The descending serotoninergic raphespinal tract represents new potential therapeutic targets against colorectal dysmotility such as irritable bowel syndrome.

In vivo release of serotonin in cat dorsal vagal complex and cervical ventral horn induced by electrical stimulation of the medullary raphe nuclei

1990 ◽  
Vol 535 (2) ◽  
pp. 227-236 ◽  
Author(s):  
Ernst Brodin ◽  
Bengt Linderoth ◽  
Michel Goiny ◽  
Yuji Yamamoto ◽  
Bertil Gazelius ◽  
...  
Keyword(s):  
Electrical Stimulation ◽  
Ventral Horn ◽  
Raphe Nuclei ◽  
Dorsal Vagal Complex ◽  
In Vivo Release ◽  
Medullary Raphe ◽  
Raphé Nuclei ◽  
Stimulation Of

scholarly journals Neuropeptide VF neurons promote sleep via the serotonergic raphe

2019 ◽  
Author(s):  
Daniel A. Lee ◽  
Grigorios Oikonomou ◽  
Tasha Cammidge ◽  
Young Hong ◽  
David A. Prober
Keyword(s):  
Calcium Imaging ◽  
Neural Circuit ◽  
Raphe Nuclei ◽  
Hypothalamic Neurons ◽  
Optogenetic Stimulation ◽  
Genetic Epistasis ◽  
Normal Sleep ◽  
Genetic Labeling ◽  
Raphé Nuclei ◽  
Stimulation Of

ABSTRACTAlthough several sleep-regulating neurons have been identified, little is known about how they interact with each other for sleep/wake control. We previously identified neuropeptide VF (NPVF) and the hypothalamic neurons that produce it as a sleep-promoting system (Lee et al., 2017). Here we use zebrafish to describe a neural circuit in which neuropeptide VF (npvf)-expressing neurons control sleep via the serotonergic raphe nuclei (RN), a hindbrain structure that promotes sleep in both diurnal zebrafish and nocturnal mice. Using genetic labeling and calcium imaging, we show that npvf-expressing neurons innervate and activate serotonergic RN neurons. We additionally demonstrate that optogenetic stimulation of npvf-expressing neurons induces sleep in a manner that requires NPVF and is abolished when the RN are ablated or lack serotonin. Finally, genetic epistasis demonstrates that NPVF acts upstream of serotonin in the RN to maintain normal sleep levels. These findings reveal a novel hypothalamic-hindbrain circuit for sleep/wake control.

scholarly journals Central and peripheral chemoreceptors evoke distinct responses in simultaneously recorded neurons of the raphé-pontomedullary respiratory network

2009 ◽  
Vol 364 (1529) ◽  
pp. 2501-2516 ◽  
Author(s):  
Sarah C. Nuding ◽  
Lauren S. Segers ◽  
Roger Shannon ◽  
Russell O'Connor ◽  
Kendall F. Morris ◽  
...  
Keyword(s):  
Network Architecture ◽  
Motor Pattern ◽  
Specific Interaction ◽  
Raphe Nuclei ◽  
Short Time Scale ◽  
Peripheral Chemoreceptor ◽  
Peripheral Chemoreceptors ◽  
Central Chemoreceptors ◽  
Raphé Nuclei ◽  
Stimulation Of

The brainstem network for generating and modulating the respiratory motor pattern includes neurons of the medullary ventrolateral respiratory column (VRC), dorsolateral pons (PRG) and raphé nuclei. Midline raphé neurons are proposed to be elements of a distributed brainstem system of central chemoreceptors, as well as modulators of central chemoreceptors at other sites, including the retrotrapezoid nucleus. Stimulation of the raphé system or peripheral chemoreceptors can induce a long-term facilitation of phrenic nerve activity; central chemoreceptor stimulation does not. The network mechanisms through which each class of chemoreceptor differentially influences breathing are poorly understood. Microelectrode arrays were used to monitor sets of spike trains from 114 PRG, 198 VRC and 166 midline neurons in six decerebrate vagotomized cats; 356 were recorded during sequential stimulation of both receptor classes via brief CO 2 -saturated saline injections in vertebral (central) and carotid arteries (peripheral). Seventy neurons responded to both stimuli. More neurons were responsive only to peripheral challenges than those responsive only to central chemoreceptor stimulation (PRG, 20 : 4; VRC, 41 : 10; midline, 25 : 13). Of 16 474 pairs of neurons evaluated for short-time scale correlations, similar percentages of reference neurons in each brain region had correlation features indicative of a specific interaction with at least one target neuron: PRG (59.6%), VRC (51.0%) and raphé nuclei (45.8%). The results suggest a brainstem network architecture with connectivity that shapes the respiratory motor pattern via overlapping circuits that modulate central and peripheral chemoreceptor-mediated influences on breathing.

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