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  • 1
    Electronic Resource
    Electronic Resource
    A Comparison of Biochemical Indices of 5-Hydroxytryptaminergic Neuronal Activity Following Electrical Stimulation of the Dorsal Raphe Nucleus (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 47 (1986), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: The activity of 5-hydroxytryptaminergic neurons has been estimated from measurements of: (1) concentrations of 5-hydroxyindoleacetic acid; (2) the ratio of the concentrations of 5-hydroxyindoleacetic acid to 5-hydroxytryptamine; (3) the rate of accumulation of 5-hydroxytryptophan following the administration of an aromatic l-amino acid decarboxylase inhibitor (e.g., NSD 1015); (4) the rate of accumulation of 5-hydroxytryptamine, and the rate of decline of 5-hydroxyindoleacetic acid following the administration of a monoamine oxidase inhibitor (e.g., pargyline). The purpose of the present study was to compare these different methods under conditions of changing neuronal impulse traffic produced by electrical stimulation of 5-hydroxytryptaminergic neurons. Male rats anesthetized with chloral hydrate were killed following 0, 15, or 30 tain of electrical stimulation of the dorsal raphe nucleus at a frequency of 0, 5, or 10 Hz. The concentrations of 5-hydroxytryptamine, 5-hydroxyindoleacetic acid, and 5-hydroxytryptophan in nucleus accumbens, amygdala, suprachiasmatic nucleus, and dorsomedial nucleus were measured using HPLC coupled to an electrochemical detector. In each brain region, stimulation elicited an increase in the concentration of 5-hydroxyindoleacetic acid and the 5-hydroxyindoleacetic acid/5-hydroxytryptamine concentration ratio in saline-treated animals and an increase in 5-hydroxytryptophan accumulation in NSD 1015-treated animals, but did not alter the concentration of 5-hydroxytryptamine or 5-hydroxyindoleacetic acid in pargyline-treated rats. The results of this study indicate that although the first three methods serve as valid indices of 5-hydroxytryptaminergic neuronal activity, the pargyline-dependent techniques are not responsive to changes in the rate of 5-hydroxytryptamine nerve firing.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1986.tb00704.x
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  • 2
    Electronic Resource
    Electronic Resource
    Exogenous Tryptophan Increases Synthesis, Storage, and Intraneuronal Metabolism of 5-Hydroxytryptamine in the Rat Hypothalamus (1986)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 47 (1986), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: The effects of tryptophan administration on neurochemical estimates of synthesis [5-hydroxytryptophan (5-HTP) accumulation following administration of a decarboxylase inhibitor], storage [5-hydroxytryptamine (5-HT) concentrations], and metabolism [5-hydroxyin-doleacetic acid (5-HIAA) concentrations] of 5-HT in selected regions of the hypothalamus were determined using HPLC coupled to an electrochemical detector. Tryptophan methyl ester HCl (30–300 mg/kg i.p.) produced a dose-dependent increase in the rate of 5-HTP accumulation throughout the hypothalamus but had no effect on the rate of accumulation of 3,4-dihydroxyphen-ylalanine. Peak 5-HTP levels were attained by 30 min following administration of tryptophan (100 mg/kg i.p.) and were maintained for an additional 60 min. Tryptophan also produced concomitant dose-dependent increases in 5-HT and 5-HIAA concentrations in these same regions without changes in the 5-HIAA/5-HT ratio. These results indicate that exogenous tryptophan administration selectively increases the synthesis, storage, and metabolism of 5-HT in the hypothalamus without altering the synthesis of catecholamines. Inhibition of 5-HT uptake with chlorimipramine or fluoxetine produced modest (10–40%) reductions in 5-HIAA concentrations throughout the hypothalamus, revealing that only a minor portion of 5-HIAA is derived from released and recaptured 5-HT, whereas the major portion of this metabolite reflects intraneuronal metabolism of unreleased 5-HT. In both chlorimipramine- and fluoxetine-treated rats, 5-HIAA concentrations were significantly increased by tryptophan administration, indicating that the increase in synthesis of 5-HT following precursor loading is accompanied by an increase in the intraneuronal metabolism of 5-HT.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1986.tb02851.x
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  • 3
    Electronic Resource
    Electronic Resource
    Simultaneous Determination of 5-Hydroxytryptophan and 3,4-Dihydroxyphenylalanine in Rat Brain by HPLC with Electrochemical Detection Following Electrical Stimulation of the Dorsal Raphe Nucleus (1985)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 44 (1985), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: HPLC coupled with electrochemical detection was used to make concurrent measurements of the rate of accumulation of 5-hydroxytryptophan and 3,4-dihydroxyphenylalanine in selected brain regions (striatum, nucleus accumbens, septum, medial periventricular hypothalamus) and thoracic spinal cords of rats treated with NSD 1015, an inhibitor of aromatic-L-amino-acid decarboxylase. 5-Hydroxytryptophan and 3,4-dihydroxyphenylalanine accumulated in all brain regions 30 min after the intravenous infusion of various doses of NSD 1015; there were no significant differences in the responses to 12.5, 25, 50, and 100 mg/kg. After the intravenous administration of 25 mg/kg NSD 1015 the concentrations of 5-hydroxytryptophan and 3,4-dihydroxyphenylalanine increased linearly with time in all brain regions for at least 30 min. Electrical stimulation of 5-hydroxytryptamine neurons in the dorsal raphe nucleus for 30 min at 5 or 10 Hz increased 5-hydroxytryptophan accumulation in all brain regions but not in the spinal cord. Unexpectedly, this stimulation also increased the accumulation of 3,4-dihydroxyphenylalanine in the hypothalamus and spinal cord. These results suggest that 5-hydroxytryptophan accumulation following the administration of NSD 1015 is a valid index of 5-hydroxytryptamine neuronal activity in the brain.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1985.tb07121.x
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  • 4
    Electronic Resource
    Electronic Resource
    EFFECTS OF PRE- OR POSTNATAL DEXAMETHASONE, ADRENOCORTICOTROPHIC HORMONE AND ENVIRONMENTAL STRESS ON PHENYLETHANOLAMINE N-METHYLTRANSFERASE ACTIVITY AND CATECHOLAMINES IN SYMPATHETIC GANGLIA OF NEONATAL RATS (1977)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 28 (1977), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Injections of dexamethasone (0.1 mg/kg/day, s.c.) on the first 2–3 days of life increased the phenylethanolamine-N-methyltransferase (PNMT) activity and epinephrine content of the superior cervical ganglion (SCG) and stellate ganglion of neonatal rats; the dopamine content was unaltered while norepinephrine was slightly reduced in these ganglia. Dexamethasone did not alter the PNMT activity or epinephrine content of the salivary glands or heart. The PNMT activity and epinephrine content of the SCG remained elevated for 10–14 days. Pretreatment with 6-hydroxydopamine did not alter the dexamethasone effects.Injections of adrenocorticotrophic hormone (ACTH) (25 munits/rat twice a day) or exposure to a cold stress (4°C, 3 times a day) on the first 2–3 days of life, elevated the plasma concentration of corticosterone, and also increased the PNMT activity and epinephrine content in SCG of neonatal rats. Injecting pregnant rats with dexamethasone or ACTH, or exposing them to cold or restraint stress on the last 3 days of gestation increased the PNMT activity and epinephrine content in the SCG of their pups. These results indicate that the actions of dexamethasone on neonatal sympathetic ganglia may be mimicked by increasing the plasma concentration of endogenous adrenocortical steroids.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1977.tb10653.x
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  • 5
    Electronic Resource
    Electronic Resource
    EFFECTS OF DEXAMETHASONE ON PHENYLETHANOLAMINE N-METHYLTRANSFERASE AND ADRENALINE IN THE BRAINS AND SUPERIOR CERVICAL GANGLIA OF ADULT AND NEONATAL RATS (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 25 (1975), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Phenylethanolamine N-methyltransferase (PNMT) activity assayed by a sensitive radiochemical method was found to be distributed unevenly in the adult rat brain. Highest activities of this enzyme were located in the medulla and the hypothalamus. Small amounts of adrenaline were identified in the hypothalamus using a sensitive enzymatic radiochemical assay procedure, whereas in the medulla and other brain regions the values for adrenaline were at the limits of the sensitivity of the assay for this amine. The daily administration of dexamethasone (1 mg/kg) to adult rats for 13 days significantly increased PNMT activity in medulla and hypothalamus and also increased the adrenaline content of the hypothalamus. Five daily injections of dexamethasone (0·1 mg/kg) to newborn rats did not alter the PNMT activity or the catecholamine content of the brain, but markedly increased the PNMT activity and adrenaline content of superior cervical ganglia. Higher doses of dexamethasone given to newborn rats (6 daily injections of 1 mg/kg) increased PNMT activity both in the medulla and in the hypothalamus.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1975.tb06968.x
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  • 6
    Electronic Resource
    Electronic Resource
    EFFECTS OF DEXAMETHASONE AND NERVE GROWTH FACTOR ON PHENYLETHANOLAMINE N-METHYLTRANSFERASE AND ADRENALINE IN ORGAN CULTURES OF NEWBORN RAT SUPERIOR CERVICAL GANGLION (1975)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 25 (1975), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— Phenylethanolamine N-methyltransferase (PNMT) and adrenaline (A) have been studied in organ cultures of neonatal rat sympathetic ganglia. Organ culture for 2 days without added nerve growth factor (NGF) caused a fall in noradrenaline (NA) and PNMT contents but there was no change in dopamine (DA) or A contents compared to controls. However, in the presence of dexamethasone, there was a marked increase in both PNMT activity and A content, but no change in NA or DA content. Addition of NGF to cultures stimulated with dexamethasone caused no further significant change in PNMT activity or A content, whereas both NA and DA were increased. Prolonged culture without NGF, in the presence of dexamethasone resulted in reductions in both NA and DA content, but the high levels of PNMT activity and A content were sustained. The results are consistent with the hypothesis that both PNMT and A are not contained in the noradrenergic cell bodies but are located chiefly within the small intensely fluorescent cells in sympathetic ganglia.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1975.tb06969.x
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  • 7
    Electronic Resource
    Electronic Resource
    IN VIVO RELEASE OF ENDOGENOUSLY SYNTHESIZED CATECHOLAMINES FROM THE CAT BRAIN EVOKED BY ELECTRICAL STIMULATION AND BY d-AMPHETAMINE (1974)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 23 (1974), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract— The cerebral ventricles of spinal-sectioned cats were perfused with artificial cerebrospinal fluid after the intraventricular administration of [3H]DOPA or [3H]tyrosine. Endogenously synthesized [3H]dopamine or [3H]norepinephrine were identified in the perfusate. Electrical stimulation of catecholaminergic nerve tracts in the hypothalamus increased the efflux of both catecholamines. The addition of d-amphetamine to the perfusing cerebrospinal fluid caused a large increase in [3H]dopamine and a small increase in [3H]norepinephrine appearing in the perfusate. Most of the endogenously synthesized [3H]catecholamines detected in the perfusate following stimuli originated from structures bordering the lateral cerebral ventricle. Thus, norepinephrine and dopamine can be synthesized in and released from catecholaminergic nerve terminals in structures bordering the cerebral ventricles.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1974.tb06930.x
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  • 8
    Electronic Resource
    Electronic Resource
    EFFECTS OF DOPAMINERGIC AGONISTS AND ELECTRICAL STIMULATION OF THE MIDBRAIN RAPHÉ ON THE RELEASE OF 5-HYDROXYTRYPTAMINE FROM THE CAT BRAIN IN VIVO (1976)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 26 (1976), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: —The cerebroventricular system of spinal-sectioned cats was perfused with artificial cerebrospinal fluid after the intraventricular administration of [3H]tryptophan, and the perfusate was analyzed for [3H]5-HT. At the end of the experiment the relative contents of [3H]5-HT in regions lining the cerebroventricular system (caudate nucleus, septum, hypothalamus) were essentially the same as the endogenous 5-HT contents. Electrical stimulation of the midbrain raphé did not alter the efflux of total radioactivity but significantly increased the efflux of [3H]5-HT. The addition of potassium to the perfusing CSF also increased the efflux of [3H]5-HT, while additions of d-amphetamine, apomorphine or l-DOPA were without effect.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1976.tb04483.x
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  • 9
    Electronic Resource
    Electronic Resource
    Neuroleptics and Neuroendocrine Function (1988)
    Palo Alto, Calif. : Annual Reviews
    Annual Review of Pharmacology 28 (1988), S. 347-366 
    Details
    ISSN: 0362-1642
    Source: Annual Reviews Electronic Back Volume Collection 1932-2001ff
    Topics: Medicine , Chemistry and Pharmacology
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1146/annurev.pa.28.040188.002023
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  • 10
    Electronic Resource
    Electronic Resource
    Effects of Chloral Hydrate, γ-Butyrolactone, and Equithesin on the Efflux of Dopamine and 5-Hydroxytryptamine Metabolites into Cerebroventricular Perfusates of Rats (1982)
    Oxford, UK : Blackwell Publishing Ltd
    Journal of neurochemistry 39 (1982), S. 0 
    Details
    ISSN: 1471-4159
    Source: Blackwell Publishing Journal Backfiles 1879-2005
    Topics: Medicine
    Notes: Abstract: Chloral hydrate, γ-butyrolactone, and Equithesin are general anesthetics which have been employed in a variety of neurochemical and electrophysiological experiments. The effects of these anesthetics on the efflux of dopamine and 5-hydroxytryptamine metabolites into lateral cerebroventricular perfusates were determined in rats bearing chronically implanted cannulas. Chloral hydrate and Equithesin increased, whereas γ-butyrolactone decreased, the efflux of the dopamine metabolites 3,4-dihydroxyphenylacetic acid and homovanillic acid. None of the anesthetics had a consistent effect on the efflux of the 5-hydroxytryptamine metabolite 5-hydroxyindoleacetic acid.
    Type of Medium: Electronic Resource
    URL: http://dx.doi.org/10.1111/j.1471-4159.1982.tb04724.x
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