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Functional topography of serotonergic systems supports the Deakin/Graeff hypothesis of anxiety and affective disorders.

Over 20 years ago, Deakin and Graeff hypothesized about the role of different serotonergic pathways in controlling the behavioral and physiologic responses to aversive stimuli, and how compromise of these pathways could lead to specific symptoms of anxiety and affective disorders. A growing body of evidence suggests these serotonergic pathways arise from topographically organized subpopulations of serotonergic neurons located in the dorsal and median raphe nuclei. We argue that serotonergic neurons in the dorsal/caudal parts of the dorsal raphe nucleus project to forebrain limbic regions invol…

Control of coughing by medullary raphé.

The medullary raphé nuclei participate in the regulation of breathing and airway defensive reflexes. Our focus was to analyze the effects of codeine and kainic acid within the medullary raphé on coughing, sneezing, solitary expulsions, and concomitant breathing changes using models of anesthetized cats (n=12) and rabbits (n=15) and microinjection techniques. Our findings are consistent with (1) involvement of neurons within the medullary raphé in the generation of the cough motor pattern by a codeine-sensitive and -insensitive mechanisms, (2) a contribution of raphé nuclei to the control of ex

Serotoninergic and non-serotoninergic responses of phrenic motoneurones to raphe stimulation in the cat.

Experiments were conducted on anaesthetized, paralysed and artificially ventilated cats in order to determine if the altered discharge pattern of phrenic motoneurones recorded during stimulation of medullary raphe nuclei (raphe magnus (r. magnus), raphe obscurus (r. obscurus), raphe pallidus (r. pallidus] are related to release of serotonin (5-hydroxytryptamine, 5-HT) at synapses on respiratory neurones. Effects of 5-HT released by the neurotoxin p-chloroamphetamine (PCA) on spontaneous activity of phrenic motoneurones were also examined. In addition, responses of phrenic motoneurones to 5-HT …

The influence of respiration on brainstem and cardiovagal response to auricular vagus nerve stimulation: A multimodal ultrahigh-field (7T) fMRI study.

BACKGROUND: Brainstem-focused mechanisms supporting transcutaneous auricular VNS (taVNS) effects are not well understood, particularly in hu … o eRAVANS was significantly greater than iRAVANS for all nuclei, and greater than GANctrl in LC and raphe nuclei. Furthermore, eRAVANS, but not iRAVANS, enhanced cardiovagal modulation, confirming enhanced eRAVANS response on both central and peripheral neurophysiological levels. CONCLUSION: 7T fMRI localized brainstem response to taVNS, linked such response …

The brainstem connections of the supplementary motor area and its relations to the corticospinal tract: Experimental rat and human 3-tesla tractography study.

Although the supplementary motor area (SMA) is a large region on the medial surface of the frontal lobe of the brain, little is known about … rs reticulata, ventral tegmental area, inferior colliculus, mesencephalic reticular, tegmental, and raphe nuclei), pontine (locus coeruleus, pontine reticular and vestibular nuclei), and medullary (area postrema, parabrachial, and medullary reticular nuclei) structures. The anterograde tracer BDA injections into the SMA showed efferent connections with mesence …

The effect of complex double-axis rotation model on GABAergic neurons in caudal ventrolateral medulla of rats along the vestibulo-sympathetic reflex pathway.

INTRODUCTION: Motion sickness is a common physiological disorder induced by with unusual movement exposure, characterized by conflicting mot … Our results revealed a bilateral distribution of GABAergic neurons, predominantly within the caudal raphe nuclei. Notably, a subset of these neurons was activated (as indicated by Fos immunoreactivity) and projected to the CVLM (as shown by retrograde labeling with FG) under complex double-axis rotation model. Furthermore, these same neurons also received dire …

Топография инфонтенторных повреждений в депрессии и тревоге при множественном склерозе.

БОЛЕЕ: Депрессия и тревога широко распространены при множественном склерозе и оказывают значительное воздействие на результаты лечения пациентов. Однако их связь с конкретными областями обезвоживания остается неясной. ЗАДАЧИ: В настоящем исследовании рассматривается связь между инфантентными повреждениями и депрессией или тревогой с уделением особого внимания трем областям, представляющим интерес: рэфе-нуклей, колокольчик коэулеус и мозговой лобуле VIIА. В клинике когнитивной нейроиммунологии Королевской мельбурнской больницы были приняты на работу пациенты. Участники были отнесены к группам "

Совпадение в аннотации оригинала
BACKGROUND: Depression and anxiety are highly prevalent in multiple sclerosis and significantly impact patient outcomes. However, their link to specific areas of demyelination remains unclear. OBJECTIVES: This study examines the association between infratentorial lesions and depression or anxiety, focusing on three regions of interest: raphe nuclei, locus c…

Impact of adolescent ethanol binge on serotonin signaling and pain sensitivity post-withdrawal.

Adolescence is a critical neurodevelopmental period characterized by heightened neuroplasticity. While the acute effects of binge ethanol (EtOH) consumption are documented, its long-term impact on both pain sensitivity and microglial activation during adolescence remains unclear. Given serotonin's (5-HT) known involvement in pain processing and sensitivity to EtOH, this study examined the effects of adolescent EtOH binge on microglia-induced neuroinflammation in serotonergic nuclei, downstream 5-HT signaling, and pain sensitivity at different time points after EtOH withdrawal. Adolescent male

Release of transmitters into the perfused third cerebral ventrical of the cat.

1. The third cerebral ventricle of cats treated with nialamide and anaesthetized with chloralose was perfused, and the effluent was tested f … as the reticular formation or the decussation of the superior cerebellar peduncles, but not the two raphe nuclei.4. Low frequencies of stimulation were more effective at releasing 5-HT, and high frequencies at releasing ACh.5. Since the amount of 5-HT released on stimulation was rarely more than 2 ng, a powerful re-uptake process was suspected and confirmed by …

[Involvement of serotoninergic systems in analgesia induced by electrical stimulation of brain stem areas (author's transl)].

Numerous studies in the rat have shown that powerful analgesia can be induced by electrical stimulation of the periaqueductal grey matter (PGM). From an extensive mapping (300 sites of stimulation) performed on unrestrained cats, we have demonstrated that the points from which analgesia can be obtained are essentially located in the raphe nuclei: dorsal raphe nucleus (DRN) located in the ventral part of the PGM, superior part of the nucleus central superior (CS) and nucleus central inferior (mainly the raphe magnus: RM). The most powerful effects were induced by stimulation sites located in th…

Brainstem Raphe Echogenicity and Insomnia in Type 2 Diabetes: An Exploratory Cross-Sectional Study.

BACKGROUND: Type 2 diabetes mellitus (T2DM) is associated with increased vulnerability to depression and other affective disturbances, potentially mediated by neurobiological alterations in the serotonergic brainstem raphe nuclei. This study examined whether raphe hypoechogenicity, assessed by transcranial sonography, is associated with depressive, anxiety, and sleep-related symptoms in individuals with T2DM, and whether such alterations are linked to diabetes-related complications. METHODS: This cross-sectional study included 230 participants with T2DM and non-diabetic controls. Raphe echoge…

Involvement of medullary regions controlling sympathetic output in Lewy body disease.

We sought to determine the involvement of medullary regions controlling sympathetic output in pathologically confirmed diffuse Lewy body dis … an hydroxylase and alpha-synuclein. Analysis was focused on the ventrolateral medulla and medullary raphe nuclei. In LBD cases, there were Lewy bodies and neurites, as well as dystrophic neurons in the ventrolateral medulla, but the number of catecholaminergic and serotonergic neurons was not significantly reduced. All these groups were depleted in MSA. There …

Activation of the parapyramidal region in the ventral medulla stimulates gastric acid secretion through vagal pathways in rats.

Neurons synthesizing thyrotropin-releasing hormone, substance P and serotonin in the medullary caudal raphe nuclei project to the dorsal vagal complex and play a role in the central vagal regulation of gastric function. Neurons in the parapyramidal region in the ventral medulla share similar biochemical coding and projections as those in the caudal raphe nuclei. The role of the parapyramidal region in the autonomic regulation of gastric acid secretion was investigated in urethane-anesthetized rats. Unilateral microinjection of kainate into the parapyramidal region at 10, 15 and 20 ng induced a…

Substance P in the dorsal vagal complex inhibits medullary TRH-induced gastric acid secretion in rats.

Neurons that contain substance P (SP) and thyrotropin-releasing hormone (TRH) in medullary midline raphe nuclei project to the dorsal vagal complex (DVC). The modulatory role of SP on basal gastric acid secretion (GAS) and TRH on DVC-induced stimulation of GAS was studied in urethan-anesthetized rats. The stable SP agonist, DiMe-C7 ([pGlu5, MePhe8, MeGly9]SP5-11, 50 and 100 pmol), injected unilaterally into the DVC reduced the GAS response (47 +/- 12 mumol/60 min) to coinjected TRH analog, RX 77368 (25 pmol), by 53% and 85%, respectively, whereas DiMe-C7 (100 pmol) alone had no effect on basal…

Spinocerebellar ataxia type 4 (SCA4): Initial pathoanatomical study reveals widespread cerebellar and brainstem degeneration.

Spinocerebellar ataxia type 4 (SCA4), also known as 'hereditary ataxia with sensory neuropathy', represents a very rare, progressive and untreatable form of an autosomal dominant inherited cerebellar ataxia (ADCA). Due to a lack of autopsy cases, no neuropathological or clinicopathological studies had yet been performed in SCA4. In the present study, the first available cerebellar and brainstem tissue of a clinically diagnosed and genetically-confirmed German SCA4 patient was pathoanatomically studied using serial thick sections. During this systematic postmortem investigation, along with an o

Seizure-dependent mTOR activation in 5-HT neurons promotes autism-like behaviors in mice.

Epilepsy and autism spectrum disorder (ASD) are common comorbidities of one another. Despite the prevalent correlation between the two disorders, few studies have been able to elucidate a mechanistic link. We demonstrate that forebrain specific Tsc1 deletion in mice causes epilepsy and autism-like behaviors, concomitant with disruption of 5-HT neurotransmission. We find that epileptiform activity propagates to the raphe nuclei, resulting in seizure-dependent hyperactivation of mTOR in 5-HT neurons. To dissect whether mTOR hyperactivity in 5-HT neurons alone was sufficient to recapitulate an au…

Sleep architecture and sleep-disordered breathing in fatal insomnia.

STUDY OBJECTIVES: Fatal insomnia (FI) is a rare prion disease severely affecting sleep architecture. Breathing during sleep has not been sys … p occurred in short segments in nine patients, and their reduced duration correlated with medullary raphe nuclei degeneration (r = -0.9, p = 0.005). Seven patients had REM without atonia. Three vPSG patterns were identified: agitated, with aperiodic, manipulative, and finalistic movements (n = 4); quiet-apneic, with CSA (n = 4); and quiet-non-apneic (n = 3). …

Brain-encysting trematodes (Euhaplorchis californiensis) decrease raphe serotonergic activity in California killifish (Fundulus parvipinnis).

Modulation of brain serotonin (5-HT) signalling is associated with parasite-induced changes in host behaviour, potentially increasing parasite transmission to predatory final hosts. Such alterations could have substantial impact on host physiology and behaviour, as 5-HT serves multiple roles in neuroendocrine regulation. These effects, however, remain insufficiently understood, as parasites have been associated with both increased and decreased serotonergic activity. Here, we investigated effects of trematode Euhaplorchis californiensis metacercariae on post-stress serotonergic activity in the

Perinatal Nicotine Reduces Chemosensitivity of Medullary 5-HT Neurons after Maturation in Culture.

Perinatal exposure to nicotine produces ventilatory and chemoreflex deficits in neonatal mammals. Medullary 5-HT neurons are putative central chemoreceptors that innervate respiratory nuclei and promote ventilation, receive cholinergic input and express nicotinic acetylcholine receptors (nAChRs). Perforated patch clamp recordings were made from cultured 5-HT neurons dissociated from the medullary raphé of 0-3 day old mice expressing enhanced yellow fluorescent protein driven by the enhancer region for PET1 (ePet-EYFP). The effect of exposure to low (6 mg kg-1day-1) or high (60 mg kg-1day-1) do

The structure of the dorsal raphe nucleus and its relevance to the regulation of sleep and wakefulness.

Serotonergic (5-HT) cells in the rat dorsal raphe nucleus (DRN) appear in topographically organized groups. Based on cellular morphology, expression of other neurotransmitters, afferent and efferent connections and functional properties, 5-HT neurons of the DRN have been grouped into six cell clusters. The subdivisions comprise the rostral, ventral, dorsal, lateral, caudal and interfascicular parts of the DRN. In addition to 5-HT cells, neurons containing γ-aminobutyric acid (GABA), glutamate, dopamine, nitric oxide and the neuropeptides corticotropin-releasing factor, substance P, galanin, ch