Search results for "Dorsal raphe nucleu"

c-fos expression, behavioural, endocrine and autonomic responses to acute social stress in male rats after chronic restraint: modulation by serotonin

2000

The effects in male rats of serotonin depletion (using the neurotoxin 5,7-dihydroxytryptamine) on the cross-sensitization of an acute social stress (defeat by a larger resident male) by previous repeated restraint stress (10 days, 60 min per day) was studied. Previous restraint increased freezing responses during social defeat in sham-operated rats, but this was not observed in those with depleted serotonin (83% or more in different regions of the brain). In contrast, neither heart rate (tachycardia) nor core temperature responses (hyperthermia) were accentuated in previously restrained rats (i.e. neither showed heterotypical sensitization), and neither adapted to repeated restraint (there …

Lateral habenula and hippocampal units: electrophysiological and iontophoretic study

1995

In previous works we studied, on cats, the effects of lateral habenula (LH) stimulation on hippocampal units. In particular, the results showed an excitation or an inhibition in relation to the stimulation frequency (0.5-3.0 Hz or 5.0-20 Hz, respectively). All the LH stimulation effects were antagonised by iontophoretic intrahippocampal application of methysergide (MS). In this series of experiments it was possible to demonstrate, on rats, that LH stimulation causes an excitatory effect in a major number of hippocampal units in relation to the frequency increase. The inhibitory effect by iontophoretic serotonine application and the reversible blockade of habenular modulation after iontophor…

Effect of chronic citalopram on serotonin-related and stress-regulated genes in the dorsal raphe nucleus of the rat

2007

Using a model of depression in which chronic social stress induces depressive-like symptoms, we investigated effects of the selective serotonin-reuptake inhibitor (SSRI) citalopram on gene expression in the dorsal raphe nucleus of male rats. Expression of tryptophan hydroxylase (TPH) protein was found to be upregulated by the stress and normalized by citalopram, while mRNAs for genes TPH 1 and 2 were differentially affected. Citalopram had no effect on serotonin transporter mRNA but reduced serotonin-1A autoreceptor mRNA in stressed animals. The SSRI prevented the stress-induced upregulation of mRNA for CREB binding protein, synaptic vesicle glycoprotein 2b and the glial N-myc downstream-re…

Nucleus incertus—An emerging modulatory role in arousal, stress and memory

2011

A major challenge in systems neuroscience is to determine the underlying neural circuitry and associated neurotransmitters and receptors involved in psychiatric disorders, such as anxiety and depression. A focus of many of these studies has been specific brainstem nuclei that modulate levels of arousal via their ascending monoaminergic projections (e.g. the serotonergic dorsal raphe, noradrenergic locus ceruleus and cholinergic laterodorsal tegmental nucleus). After years of relative neglect, the subject of recent studies in this context has been the GABAergic nucleus incertus,1 which is located in the midline periventricular central gray in the ‘prepontine’ hindbrain, with broad projection…

Afferent and efferent connections of the olfactory bulbs in the lizard Podarcis hispanica.

1991

The connections of the olfactory bulbs of Podarcis hispanica were studied by tract-tracing of injected horseradish peroxidase. Restricted injections into the main olfactory bulb (MOB) resulted in bilateral terminallike labeling in the medial part of the anterior olfactory nucleus (AON) and in the rostral septum, lateral cortex, nucleus of the lateral olfactory tract, and ventrolateral amygdaloid nucleus. Bilateral retrograde labeling was found in the rostral lateral cortex and in the medial and dorsolateral AON. Ipsilaterally the dorsal cortex, nucleus of the diagonal band, lateral preoptic area, and dorsolateral amygdala showed labeled cell bodies. Retrogradely labeled cells were also foun…

Serotonergic versus non-serotonergic dorsal raphe projection neurons differential participation in reward circuitry

ROLE OF DORSAL RAPHE NUCLEUS AND VENTRAL TEGMENTAL AREA ON REWARD AND FEEDING BEHAVIORS IN MICE

Central Serotonin2C Receptor: From Physiology to Pathology

2006

Since the 1950s, when serotonin (5-HT) was discovered in the mammalian central nervous system (CNS), an enormous amount of experimental evidence has revealed the pivotal role of this biogenic amine in a number of cognitive and behavioural functions. Although 5-HT is synthesized by a small group of neurons within the raphe nuclei of the brain stem, almost all parts of the CNS receive serotonergic projections. Furthermore, the importance of 5-HT modulation and the fine-tuning of its action is underlined by the large number of 5-HT binding sites found in the CNS. Hitherto, up to 15 different 5-HT receptors subtypes have been identified. This review was undertaken to summarize the work that has…