These experiments were performed to investigate the effect of saline, stress, imipramine, stress -imipramine and/or stress -tryptophan on serotonin immunoreactivity in raphe nucleus of the rats (200 ~220 g, body weight). The animals were injected i.p. with imipramine (15 mg/kg) and tryptophan (15 mg/kg) after electric shocks for 20 days. The result by immunohistochemical methods were as follows; 1. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were significantly increased in stress treated group compared to saline treated group. 2. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were decreased in imipramine treated group compared all the other group. 3. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were significantly decreased in stress -imipramine treated group compared to stress alone treated group but were significantly increased in stress -imipramine treated group compared to imipramine treated group. 4. Serotonin -immunoreactive neurons in the raphe nucleus of midbrain were significantly increased in stress -tryptophan treated group compared to stress alone and saline treated group. These experiments indicated that serotonin immunoreactive neurons in raphe nucleus of midbrain were increased due to the activation of stress and decreased by suppresing activation of stress through imipramine treatment.
Animals ; Imipramine* ; Mesencephalon ; Neurons ; Raphe Nuclei* ; Rats* ; Serotonin ; Shock ; Tryptophan*

No abstract available.
Animals ; Brain Stem* ; Cricetinae* ; Raphe Nuclei* ; Serotonergic Neurons*

These experiments were performed to investigate the effect of saline, tryptophan, tryptophan-imipramine and/or imipramine on serotonin immunoreactivity in raphe nucleus of midbrain of the rats (180~200 g, body weight). The animals were injected i.p. with tryptophan (15 mg/kg) and imipramine (15 mg/kg) for 20 days. The result by immunohistochemical methods were as follows; 1. Serotonin-immunoreactive neurons in the raphe of midbrain were significantly increased in tryptophan treated group compared to imipramine treated group. 2. Serotonin-immunoreactive neurons in the raphe of midbrain were decreased in imipramine treated group compared all the other group. 3. Serotonin-immunoreactive neurons in the raphe of midbrain were significantly decreased in tryptophanimipramine treated group compared to imipramine treated group. These experiments indicated that serotonin immunoreactive neurons in raphe of midbrain were increased due to the activation of tryptophan and decreased by suppresing activation of tryptophan through imipramine treatment.
Animals ; Imipramine* ; Mesencephalon* ; Neurons ; Raphe Nuclei* ; Rats* ; Serotonin ; Tryptophan*

This study was carried out to investigate the distribution of serotonin-immunoreactive neruons in the raphe nucleus of the ataxic pogo (pogo/pogo) mice derived from a Korean wild mice. Using by immunohistochemistry, we undertook to elucidate any correlation between the serotonin expression and behavior ataxia including abnormal hindlimb extension in the ataxic pogo mice. The present study has two important findings. First, serotonin immunoreactivity was increased in the raphe nucleus of the ataxic pogo mice. Second, serotonin immunoreactivity was different with the region of raphe nucleus. In the dorsal part of dorsal raphe nucleus (DRD), ventrolateral part of dorsal raphe nucleus (DRVL) and median raphe nucleus (MR), serotonin immunoreactivity was increased, whereas the ventral part of dorsal raphe nucleus (DRV) and interfascicular part of dorsal raphe nucleus (DRI) was similar with the control mice. Therefore, elevated expression of the serotonin in the raphe nucleus of ataxic pogo mice might be a source of behavior ataxia and may be related with the induction of the ataxic phenotype including abnormal hindlimb movements.
Animals ; Ataxia ; Hindlimb ; Immunohistochemistry ; Mice* ; Neurons* ; Phenotype ; Raphe Nuclei* ; Serotonin

These experiments were performed to investigate the effect of saline, melatonin, stress, stressed-melatonin on serotonin immunoreactivity in rat brain stem. The animals were injected with melatonin (1 mg/kg, i.p.) after electric shocks for 15days. The results were as follows; 1. Serotonin immunoreactive neurons in brain stem (the number of staining neuron & the stain intensity in dorsal raphe nucleus of midbrain, the stain intensity in nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla oblongata) were decreased in melatonin treated group compared with all the other groups. 2. Serotonin immunoreactive neurons in brain stem (the number of staining neuron & the stain intensity in dorsal raphe nucleus of midbrain, the stain intensity in nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla oblongata) were significantly increased in stressed group compared with all the other groups. 3. Serotonin immunoreactive neurons in brain stem(the number of staining neuron & the stain intensity in dorsal raphe nucleus of midbrain, the stain intensity in nucleus tractus solitarius and dorsal raphe nucleus of vagus nerve in medulla oblongata) were significantly decreased in stressed-melatonin treated group compared with only stressed group but were significantly increased compared with melatonin treated group. These experiments indicate that serotonin immunoreactive neurons in dorsal raphe nucleus of midbrain were increased, due to the activation of stress, and decreased when the activating of stress is suppressed through melatonin treatment.
Animals ; Brain Stem* ; Brain* ; Melatonin* ; Mesencephalon ; Neurons ; Raphe Nuclei ; Rats* ; Serotonin ; Shock ; Solitary Nucleus ; Vagus Nerve

Benzodiazepines(BZDs) are among the widely prescribed drugs in the world. They are potent anxiolytic, antiepileptic, hypnotic, and muscle relaxing agents. There is an emerging model of the role of several neural systems in anxiety and their relation to the mechanism of action of BZDs. It has been postulated that BZD drugs exert their anxiolytic action by regulating GABAergic transmission in limbic areas such as the amygdala, in the posterior hypothalamus, and in the raphe nuclei. The involvement of the amygdala in the behaviors triggered by fear and stress has been suggested by many previous studies. In this review, reports about regulatory effects of endogenous BZD receptor ligands on the perception of anxiety and memory consolidation were summerized. These findings further support the contention that BZD receptor ligands modulate memory consolidation of averse learning tasks by influencing the level of stress and/or anxiety that accompanies a learning experience. The findings suggest that the decrease in the limbic levels of BZD-like molecules seen after the various behavioral procedures represent a general response to stress and/or anxiety, since it occurs in proportion to the level of stress and/or anxiety that accompany these tasks. In addition, these findings further support the hypothesis that the GABAA/BZD receptor complex in limbic structures plays a pivotal role in the stress and anxiety.
Amygdala ; Anxiety ; Brain* ; Hypothalamus, Posterior ; Learning ; Ligands ; Memory ; Raphe Nuclei ; Receptors, GABA-A

The experimental study was performed to investigate the influence of carbon monoxide on the serotonergic neurons of the raphe nuclei in rat midbrain. For this study, Sprague Dawley rats were intoxicated with 2,000ppm carbon monoxide for 5 hours and serial sections of the midbrain were obtained and stained irnmunohistochemically using anti-serotonin anti sera. The changes in number of serotonergic neurons were analyzed. Total number of serotonergic neurons in rnidbrain of normal rats were 37,977 +/- 1,233.3 After carbon monoxide intoxication, the numbers of serotonergic neurons in midbrain nuclei were 28.138 +/- 3.321.8 CO-intoxication reduced the number of neurons in the midbrain nuclei by 25.9%. Especially diminished the number of B8 cell group by 32.6%.
Animals ; Carbon Monoxide* ; Carbon* ; Mesencephalon* ; Neurons ; Raphe Nuclei* ; Rats* ; Rats, Sprague-Dawley ; Serotonergic Neurons*

Serotonin (5-hydroxytryptamine, 5-HT) has been concerned in the pathophysiology of various neuropsychiatric disorders. It is known to modulate emotion, cognition, endocrine activity, motor function, and pain. In the present study, the effects of exogenous thyroxine (T4) on the postnatal development of serotonin-containing neuron in the rat raphe nuclei with fetal alcohol effects were investigated using immunohistochemistry. These experimental animals were divided into three groups : the alcohol-fed group received 35 calories liquid ethanol diet; the control pair-fed group was fed a liquid diet in dextrin replaced alcohol isocalorically; alcohol+T4 group received alcohol diet and exogenous thyroxine subcutaneously. After the pups were born, the pups of each were fostered by surragate mother. An average of four pups, one from each litter, were killed at days 0, 7, 14, 21, and 28 for each of the above three groups. As a result, in alcohol group, serotonin-immunoreactivity was weakly stained at all postnatal ages compared to control pair-fed and alcohol+T4 group. The intensity of serotonin immunoreactivity was more prominent in alcohlol+T4 group than in control pair-fed group at P0. Mature patterns of serotonin-containing neurons were observed in control pair-fed and alcohol+T4 group at P7. A similar developmental pattern of serotonin-containing neuron was observed on and after P7 in control pair-fed and alcohol+T4 group. These results suggest that the increase of serotonin synthesis during early postnatal life caused by maternal administration of exogenous thyroxine may ameliorate fetal alcohol effects, one of the ill effects as a result of the dysthyroid state following maternal alcohol abuse.
Alcoholism ; Animals ; Cognition ; Diet ; Ethanol ; Humans ; Immunohistochemistry ; Mothers ; Motor Activity ; Neurons* ; Raphe Nuclei* ; Rats* ; Serotonin ; Thyroxine*

OBJECTIVETo investigate the efferent pathway from the dorsal raphe nucleus to the inner ear.

METHODSEleven adult cats weighing 2.0 - 3.0 kg were used. The animals had no middle-ear disease and their auricle reflex was sensitive to sound. They were divided into experimental group (8 cats) and control group (3 cases). The fluorescent tracer cholera toxin subunit-B (CTB) was injected into cat cochlea and the CTB-labelled neurons of dorsal raphe nucleus (DRN) were identified using an immunofluorescence technique after a survival period of 7 days. For studying other fluorescence labelling, the sections containing CTB-labelled neurons were divided into four groups and incubated in antisera directed against tyrosine hydroxylase (TH), serotonin (5-HT), gamma-aminobutyric acid (GABA) and dopamine B-hydroxylase (DBH), respectively. Single-and double-labelled neurons were identified from the DRN.

RESULTS(1) A subpopulation of dorsal raphe nucleus (DRN) neurons were intensely labelled with CTB and these CTB-labelled neurons were densely distributed in a dorsomedial part of the DRN; (2) Four immunolabelling, TH, 5-HT, GABA and DBH were presented throughout the DRN. Of the total population of CTB-labelled neurons, 100% were TH-labelled neurons (double labelling) and no double-stained neuron with 5-HT, GABA and DBH was observed in the DRN.

CONCLUSIONSThere was a projection from DRN to the inner ear and this pathway might be a dopaminergic projection.

Animals ; Cats ; Ear, Inner ; innervation ; metabolism ; Efferent Pathways ; Neurons ; metabolism ; physiology ; Raphe Nuclei ; metabolism ; physiology

The present study was carried out to investigate the effect of treatment with tryptophan and/or reserpine on the raphe of medulla oblongata and mid brain of the rats (180~200 g body weight). the animal were injected i.p. with reserpine (5 mg/kg) for 3 days and tryptophan (15 mg/kg) for 20 days. The results by immunohistochemical methods were as follows: 1. Serotonin-immunoreactive neurons in the raphe of medulla oblongata and mid brain decrease in reserpine treated group compared to all the other group. 2. Serotonin-immunoreactive neurons in the raphe of medulla oblongata and mid brain were increased in tryptophan -reserpine treated group compared to the reserpine treated group but not the tryptophan treated group. 3. Serotonin-immunoreactive neurons in the raphe of medulla oblongata and mid brain were inceased in tryptophan treated group compared to all the other group. The experiments indicated that serotonin immunoreactive neurons in medulla oblongata and mid brain increased due to the activation of tryptophan and decreased by suppressing activation of tryptophan through reserpine.
Animals ; Brain ; Medulla Oblongata* ; Mesencephalon* ; Neurons ; Raphe Nuclei* ; Rats* ; Reserpine* ; Serotonin ; Tryptophan*