Optic evoked potential changes induced by deaminated metabolites of serotonin: 5-hydroxytryptophol and 5-hydroxyindole acetic acid

Resumen En el conejo no anestesiado, el acido 5-hidroxiindoleacético y el 5-hidroxitriptofol modifican los potenciales ópticos evocados de manera similar que la serotonina. Los derivados deaminados de la serotonina probablemente modulan las sinápsis serotonérgicas.     

The effect of thyroid gland on 5-Hydroxy-tryptamine (5-HT) level of brain stem and blood in rabbits

Zusammenfassung An Kaninchen wurde die Wirkung von Schilddrüsenfütterung und Thyreoidektomie auf das 5-HT-Niveau im Hirnstamm und Blut untersucht. In hyperthyreotischem Zustand ist der 5-HT-Spiegel im Blut und im Hirnstamm erhöht, bei Athyreose ist er verringert. Der Schilddrüseneffekt wird in der Veränderung des Tryptophan- Stoffwechsels über das zentrale Nerven-system gesehen.     

Characterization of the 5-HT1A receptor of the honeybee (Apis mellifera) and involvement of serotonin in phototactic behavior

Serotonin plays a key role in modulating various physiological and behavioral processes in both protostomes and deuterostomes. The vast majority of serotonin receptors belong to the superfamily of G-protein-coupled receptors. We report the cloning of a cDNA from the honeybee (Am5-ht1A) sharing high similarity with members of the 5-HT₁ receptor class. Activation of Am5-HT_1A by serotonin inhibited the production of cAMP in a dose-dependent manner (EC₅₀ = 16.9 nM). Am5-HT_1A was highly expressed in brain regions known to be involved in visual information processing. Using in vivo pharmacology, we could demonstrate that Am5-HT_1A receptor ligands had a strong impact on the phototactic behavior of individual bees. The data presented here mark the first comprehensive study—from gene to behavior—of a 5-HT_1A receptor in the honeybee, paving the way for the eventual elucidation of additional roles of this receptor subtype in the physiology and behavior of this social insect.     

Effects of thyroidectomy on monoamine oxidase activities toward tyramine and serotonin in the circumventricular nuclei of the rat.

Following thyroidectomy, monoamine oxidase (MAO) activities toward tyramine decreased significantly by 20% in the nucleus periventricularis and the nucleus arcuatus among the 3 hypothalamic nuclei of the rat, while MAO activity toward serotonin decreased significantly by 10% only in the nucleus periventricularis. It is suggested that thyroidectomy induced selective changes on the multiple forms of MAO in the discrete circumventricular nuclei.     

Effects of certain psychopharmaca on intraneuronal levels of 5-HT and catecholamines in the specific monoamine neurons of the rat brain

Zusammenfassung Die Zunahme von 5-HT, welche sich im Gehirn der Ratte nach Verabreichung von chemisch sehr verschiedenen Ganglienblockern vollzieht, konnte mit Hilfe einer hochempfindlichen histochemischen Methode auf spezifische 5-HT-Neuronen lokalisiert werden, deren Zellkörper, Axonen und Terminalen schnell ihren Amingehalt vermehren können. Bei den Katecholamin-Neuronen konnten keine deutlichen Veränderungen beobachtet werden. Tetrabenazine verursachen eine schnelle, totale Entleerung der Monoamindepots aller Teile der monoaminhaltigen Neuronen, gefolgt von einer schnellen Neubildung von Monoaminen¹⁶.

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This study was performed during tenure of a fellowship of the World Health Organization, 1964. Present address: Psychiatric Research Institute, Prague (Czechoslovakia).     

Interaction of serotonin and lysergic acid diethylamide (LSD) in the central nervous system

Zusammenfassung Serotonin (5-Oxytryptamin) wirkt bei der Maus als mildes Sedativum und steigert den hypnotischen Effekt von Evipan deutlich. Diese Wirkungssteigerung kann durch Lysergsäure-diäthylamid (LSD) antagonisiert werden. Dieser Befund stimmt mit der Ansicht überein, dem Serotonin komme eine physiologische Rolle im Gehirn zu und dass LSD möglicherweise durch antagonistische Wirkung gegenüber Serotonin Psychose verursachen kann.     

Effects of [N-(2-oxo-3,5,7-cycloheptatrien-1-yl)] aminooxoacetic acid ethyl ester (AY-25,674) on cyclic 3',5'-nucleotide formation and phosphodiesterase activity.

The orally-effective antiallergic compound [N-(2-oxo-3,5,7-cycloheptatrien-1-yl)] aminooxoacetic acid ethyl ester (AY-25,674) exhibited a potency equivalent to or 3 times less than theophylline in inhibiting guinea-pig lung and beef heart PDE, respectively, AY-25,674 did not affect the basal activity of guinea-pig lung adenyl cyclase. Although part of the antiallergic activity of AY-25,674 may be due to the ability to elevate cyclic AMP levels by PDE inhibition, other modes of action appear to be of greater relevance.     

Histochemical localization of alkaline and acid phosphatase activities in the skin ofMystus (Mystus) vittatus Bl. (Siluriformes)

Summary An attempt has been made to localize alkaline and acid phosphatase activities in the skin ofMystus vittatus by using histochemical techniques. The alkaline phosphatase activity is found in metabolically active cells such as basal columnar cells, mucous cells and polygonal support cells. The acid phosphatase activity is intense in the outermost squamous support cells and in the basal columnar cells. These activities have been correlated with some physiological functions of the epidermis.Acknowledgment. We are thankful to P. Vishwanatham, Government College, Mhow, and Dr R.S. Shrivastava, Holkar Science College, Indore, for providing laboratory facilities and to the Council of Scientific and Industrial Research, New Delhi, for a fellowship for M.S.     

A radioenzymatic method to measure picogram amounts of dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC) in small samples of brain tissue

Summary A radioenzymatic method for simultaneous determination of dopamine and DOPAC in small brain areas is described. By using this assay, 250 pg of dopamine and 150 pg of DOPAC can be estimated. The present method has been applied to compare the effect of different psychotropic drugs on the dopamine and DOPAC levels in the caudate nucleus, substantia nigra and medial basal hypothalamus.     

Stimulation of ribonuclease activity and its isoenzymes in germinating seeds of cowpea (Vigna sinensis) by gibberellic acid and adenosine-3',5-cyclic monophosphate.

Application of GA3 and cyclic AMP to cowpea seedings caused a 2-3 fold stimulation of RNAase activity, together with the augmentation of RNAase isoenzymes. Inhibitor studies indicated the requirement of fresh RNA and protein synthesis for enzyme stimulation.     

Effects of [N-(2-oxo-3,5,7-cycloheptatrien-1-yl)] aminooxoacetic acid ethyl ester (AY-25,674) on cyclic 3′,5′-nucleotide formation and phosphodiesterase activity

Summary The orally-effective antiallergic compound [N-(2-oxo-3,5,7-cycloheptatrien-1-yl)] aminooxoacetic acid ethyl ester (AY-25,674) exhibited a potency equivalent to or 3 times less than theophylline in inhibiting guinea-pig lung and beef heart PDE, respectively. AY-25,674 did not affect the basal activity of guinea-pig lung adenyl cyclase. Although part of the antiallergic activity of AY-25,674 may be due to the ability to elevate cyclic AMP levels by PDE inhibition, other modes of action appear to be of greater relevance.The authors acknowledge the excellent technical assistance of Ms M.T. Silvestre.     

Prevention of the formation of mycotoxins in whole wheat bread by citric acid and lactic acid (Mycotoxins in foodstuffs. IX)

Summary Additions of citric acid and lactic acid to whole wheat bread suppress the formation of aflatoxins byAspergillus parasiticus (0.5% citric acid, 0.75% lactic acid) and that of sterigmatocystin byA. versicolor (0.25 and 0.5% respectively).Acknowledgment. I thank Dr.R. Orth (Bundesforschungsanstalt für Ernährung, Karlsruhe, BRD) for the strain ofAspergillus versicolor.