Fluorescence histochemistry of biogenic monoamines. A study of the capacity of various carbonyl compounds to form fluorophores with biogenic monoamines in gas phase reactions.
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Acetates↗
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Monoamine oxidase activities towards biogenic monoamines in several regions of rat brain.
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Animals↗
Ontogenetic development of the monoamine oxidase activity and of the metabolism of biogenic monoamines in rat brain.
The article examines the ontogenetic development of the monoamine oxidase activity and of the metabolism of the dopamine, noradrenaline and serotonin in the brain of newborn, 10-day-, 20-day- and 2-month-old rats. Monoamine oxidase activity is determined using three substrates: tyramine, serotonin and beta-phenylethylamine. Monoamine oxidase A (substrate serotonin) and the total monoamine oxidase activity (substrate tyramine) are found to manifest identical development, their activity increasing quickly after birth, to reach constant values after the 10th day. The general course of the development during the first ten postnatal days shows that the post partum increase in the total monoamine oxidase activity in rat brain is predominantly due to monoamine oxidase A. Monoamine oxidase B (substrate beta-phenylethylamine) develops after the 10th postnatal day. Evidently monoamine oxidase A plays a decisive role for controlling the level of the biogenic monoamines in the young organism during the first days of the ontogenesis. Investigation of the changes in the content of dopamine, noradrenaline and serotonin in the age groups of the experimental animals chosen reveals a rapid increase in the dopamine and noradrenaline levels even during the first ten days of the ontogenesis. The increased total monoamine oxidase activity and the increased dopamine content correspond to its increased turnover rate during ontogenesis. The turnover rate of noradrenaline remains unchanged between the 10th and 20th postnatal days. The increasing serotonin level between the 20th and 60th post partum days corresponds to its increased turnover rate.
Aging↗
Metabolism of biogenic monoamines in the ciliated protozoan, Tetrahymena pyriformis.
1. The three-dimensional HPLC system was used to detect the presence and determine the levels of biogenic monoamines, including precursor amino acids and metabolites, simultaneously in an extract of the ciliated protozoan, Tetrahymena pyriformis. 2. Representative biogenic monoamines, such as dopamine (DA), 5-hydroxytryptamine (5-HT), epinephrine (E) and kynurenine (KYN) were found to be synthesized in Tetrahymena and released into the growth medium. 3. The following metabolic pathways were suggested to be operative: (L-DOPA)-DA-(Epinine)-E-dihydroxyphenylethyleneglycol (DOPEG)-vanillylmandelic acid (VMA) and tyrosine-4 (TYR-4)-tyramine (TYRA)-hydroxyphenylacetic acid-4 (HPAC-4) in the case of catecholamines, and tryptophan (TRP)-5-HT and TRP-KYN-xanthurenic acid (XA) in the case of indolalkylamines. 4. As judged from the released metabolites, systems for generation of biogenic monoamines in Tetrahymena seem to be active during the logarithmic phase of its growth.
Animals↗
Fluorescence methods for the histochemical demonstration of monoamines. VII. Fluorescence studies on biogenic monoamines and related compounds condensed with formaldehyde.
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Catecholamines↗
Computer-operated microspectrofluorimetry to identify formaldehyde-induced fluorophores of biogenic monoamines and precursor substances in models and tissue sections.
By means of a histochemical reaction using formaldehyde vapour (Falck and Owman 1965), biogenic monoamines and precursor substances, i.e., L-DOPA, dopamine, noradrenaline, adrenaline, 5-hydroxytryptophan and 5-hydroxytryptamine, may be converted into fluorophores with specific spectral characteristics, i.e., the emission spectrum, excitation spectrum and fading curve. The registration and correction of the spectral properties and changes induced by acidification with hydrochloric acid vapour or treatment with ammonia vapour, of these formaldehyde-induced fluorophores, are performed by an automated microspectrofluorimeter, developed by modification of a Leitz MPV 2 system. This work deals with the instrumental configuration and certain methodological features in order to identify the fluorogenic biogenic monoamines and precursor substances in models and tissue sections. Registrations of excitation peak values, for the first time extended to a wavelength range from 240-460 nm, are discussed, which enable the calculation of peak ratio values 410/260, 380/320, 320/260 or 385/315, suitable as identification parameters for formaldehyde-induced fluorophores of biogenic monoamines and precursor amino acids.
5-Hydroxytryptophan↗
Fluorescence of biogenic monoamines in the human dental pulp.
Biogenic monoamines in the adrenergic nerve terminals of the human dental pulp are demonstrated by the fluorescence method of Falck and Owman. Unmyelinated nerve fibers from nerves along alveolar blood vessels may enter the pulp, although pulp nerves are composed largely of myelinated fibers. The existence of a few sympathetic fibers is demonstrated by the fluorescence method, and possible drug effects are considered.
Biogenic Amines↗
[Biogenic monoamines in ovum cells and preimplantation embryos of mice].
Histofluorescence technique using glyoxylic acid revealed a specific fluorescence suggesting the presence of biogenic monoamines in early developmental stages of CBA x C57 Black mice. A yellow fluorescence observed in the blastomere surface from the stage of zygote up to that of four blastomere points to the presence of indole derivates. As development proceeds, the fluorescence increases and its colour becomes more and more green, which is characteristic of catecholamines. From the stage of eight blastomeres up to stage of blastocyst specific fluorescence is revealed in the cytoplasm. The inhibitors of monoamine oxidase, introduced into pregnant mice, markedly increased the specific fluorescence. An assumption is made of functional activity of biogenic monoamines in early mouse embryos.
Animals↗
Age-related changes of the effects of a group of nootropic drugs on the content of rat brain biogenic monoamines.
1. The changes in the levels of brain biogenic monoamines (BMAs) after chronic (7 days) treatment with piracetam, aniracetam and structural analogues of aniracetam (p-H, p-F, p-Cl, p-P and m-D) were studied in young and old rats. 2. An age-related significant decrease in the BMA content was established in old rats. 3. Most of the investigated compounds increased the level of one or other BMA in one or other of the brain structures studied. This elevation was predominantly established in old rats. 4. The present results and those from previous behaviour studies show that elevation of one or more of the BMA levels in one or more brain regions plays a beneficial role in the realization of their effects on the processes of learning and memory.
Aging↗
Predominant cytosolic distribution of serotonin in rat pineal gland in contrast to biogenic monoamine localization in midbrain and adrenal gland.
The subcellular distribution of serotonin and norepinephrine in the rat pineal gland was studied by tissue fractionation and compared with that of biogenic monoamines in the adrenal gland and midbrain. Homogenized tissues were fractionated by ultracentrifugation or by filtration through cellulose ester membranes. Most of the epinephrine (70-80%) and norepinephrine (62-82%) present in the adrenal glands was detected in the particulate fraction. The same distribution was found for serotonin (68.5%) and norepinephrine (59%) in the midbrain and for norepinephrine (62.5%) in the pineal gland. However, most of the serotonin in the pineal was found in the soluble fraction (89.5-98%). This suggests that the great majority of serotonin in the rat pinealocytes is cytosolic and thus is not stored in subcellular vesicles, in contrast to the biogenic monoamines in the midbrain or adrenal gland.
Adrenal Glands↗
Effects of the nootropic agents adafenoxate and meclofenoxate on brain biogenic monoamines in aged rats.
The effect of the nootropic agents meclofenoxate (Mf) and adafenoxate (Adf) on the content of biogenic monoamines in the frontal cerebral cortex, striatum, hypothalamus, and hippocampus of 22-month-old rats was studied. Mf and Adf were administered orally for seven days twice daily in a dose of 50 mg/kg weight. Both agents tested increased the content of serotonin (5-HT) in the cortex and striatum. Adf also raised the noradrenaline (NA) content in the cortex and hippocampus, lowering the dopamine (DA) level in the striatum. Comparison of the results obtained in the present study with the finding of earlier experiments of ours on 4-5-month-old rats revealed the following: 1. Biogenic monoamines (BMA) in the brain tend to decrease with ageing. 2. In addition to the unidirectional effects of Mf and Adf on the BMA content in the brain of both young and old rats, but in some cases there were also differences. 3. The comparison of the effects of Mf and Adf on the BMA content in the different brain regions with the changes in this content, characteristic of certain diseases, reveals prospects for selectivity in the application of these nootropic agents, which are generally rather similar in pharmacological characteristics.
Aging↗
Effects of the ergot alkaloid elymoclavine on the level and turnover of biogenic monoamines in the rat brain.
The effect of the clavine alkaloid elymoclavine, isolated from Claviceps sp cp II, on the level and turnover of biogenic monoamines in several rat brain structures was studied. Elymoclavine administered intraperitoneally (i.p.) at a dose of 5 mg/kg significantly increased the dopamine (DA) level in the striatum and hypothalamus and enhanced the DA turnover in the striatum. A significant increase was also found in the level and turnover of noradrenaline (NA) in the hypothalamus. Elymoclavine exerted an opposite effect on the level and turnover of serotonin (5-HT) in these brain structures: the 5-HT level significantly declined and the 5-HT turnover slightly decreased in the striatum and hypothalamus. In the cerebral cortex elymoclavine significantly increased the 5-HT level. Although the stimulant effect on DA receptors appears to be a dominant element in the mechanism of action of elymoclavine, it seems that this ergot alkaloid is also characterized by a plurireceptor action. The present results suggest a certain role for the elymoclavine action on the level and turnover of brain biogenic monoamines in the mechanism of its different pharmacological effects.
Animals↗
Effect of some monoamine oxidase inhibitors on deamination of biogenic monoamines by rat liver mitochondrial monoamine oxidase.
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Alkaloids↗
On the selective inhibition by some monoamine oxidase inhibitors of deamination of biogenic monoamines in vivo.
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Animals↗
Effects of meclofenoxate on the level and turnover of biogenic monoamines in the rat brain.
The level and turnover of biogenic monoamines in some rat brain structures were determined after treatment with meclofenoxate at a dose of 50 mg/kg administered i.p. two times a day (9 a.m. and 5 p.m.) for 5 days. Meclofenoxate decreased dopamine (DA) turnover in the frontal cortex and striatum and highly increased it in the hypothalamus. The DA level significantly declined in the striatum, tended to decline in the cortex and significantly rose in the hypothalamus. The noradrenaline (NA) turnover and level in the cortex and striatum were decreased. Meclofenoxate decreased serotonin (5-HT) turnover in the cortex, striatum and hypothalamus and increased it in the pons. At the same time, the 5-HT level rose in the cortex, striatum and pons and declined in the hypothalamus. These results suggest the neurochemical basis of the psychotropic and neuroendocrine effects of meclofenoxate.
Animals↗
[Changes in the balance of biogenic monoamines and their metabolites in the organs of rats with oxygen-induced epilepsy].
The content of some biogenic monoamines and their metabolites in rat brain and heart in different periods of oxygen epilepsia was studied using high performance liquid chromatography with electrochemical detection. It was shown that already at the 5th minute of exposure to oxygen adrenaline, DOPA and some noradrenaline metabolites disappeared in the brain and noradrenaline level reduced. At this period in rat heart the reduction of catecholamine content was the most distinct and serotonin level was unchanged. At the beginning of convulsive period the modifications of biogenic amines content were nonparallel in brain regions: in the heart the reduction of catecholamine level went on, especially in right ventricle. In the terminal phase of oxygen epilepsia brain biogenic amines increased, however, not up to normal meaning, heart catecholamines at this period were at the same level as at the beginning of the convulsive period.
Animals↗
Biogenic monoamine turnover in discrete rat brain regions is correlated with conditioned emotional response and its conditioning history.
The content and turnover of dopamine, norepinephrine and 5-hydroxytryptamine (serotonin), and the content of their respective major metabolites were evaluated in 19 discrete brain areas of rats exposed to conditioned emotional response (CER), and in control groups which received either equivalent yoked shock (shock only) or compound stimulus presentation (tone only). On test day, CER animals suppressed responding and exhibited forms of emotional behavior after presentation of the conditioned stimulus (CS); while shock only and tone only control groups, and CER animals which received an acute dose of diazepam prior to testing, did not suppress. Few changes were observed in content of the biogenic amines or their metabolites, suggesting that the behavioral manipulations were acting within normal physiological limits. On the other hand, numerous changes were observed in the utilization of the 3 biogenic monoamines, which were correlated with the conditioning-anxiety (comparisons of CER vs shock only) and the shock history (comparison of shock only vs tone only). These observations are consistent with putative neural pathways in the frontal cortex, septum, nucleus accumbens, amygdala, striatum, hippocampus and brain stem (which utilize specific monoamines), and with discrete brain areas which have been implicated in classical conditioning and CER-related phenomena. These observations suggest roles for biogenic monoamines in mediating or responding to the classical conditioning and emotional components of the paradigm.
Animals↗
Changes in the brain biogenic monoamines of rats, induced by piracetam and aniracetam.
Single oral dose of 600 mg/kg weight piracetam, respectively 50 mg/kg aniracetam, causes essential changes in the level and turnover of dopamine (DA) and serotonin (5-HT) in some rat cerebral structures. When the animals were killed one hour after the administration of the drugs, piracetam significantly increased the DA level in the cerebral cortex and in the striatum, as well as the 5-HT level in the cortex, reducing the 5-HT level in the striatum, brain stem and hypothalamus. At the same time, under the effect of piracetam the DA turnover was accelerated in the cortex and hypothalamus and delayed in the striatum, the noradrenaline turnover was accelerated in the brain stem, the 5-HT turnover was accelerated in the cortex and delayed in the striatum, stem and hypothalamus. Under the effect of aniracetam the DA level was reduced in the striatum and hypothalamus; the 5-HT level was also decreased in the hypothalamus and increased in the cortex and striatum. Aniracetam delayed the DA turnover in the striatum and the 5-HT turnover in the hypothalamus, accelerating the 5-HT turnover in the cortex, striatum and stem. The results obtained show that the changes induced in the cerebral biogenic monoamines participate in the mechanism of action of piracetam and aniracetam, whereby it seems that the analogies and differences in their effects on the cerebral biogenic monoamines play a definite role for the observed analogies and differences in the behavioural effects of these two "nootropic" compounds.
Animals↗