An assessment of the effect of hormone and neurotransmitters on adenine and guanine derivatives simultaneously in rat brain cortical slices.

A A 2-dimensional thin-layer method has been developed for the separation on cellulose of adenine and guanine derivatives. Using incubated rat cerebral cortex slices it was shown that noradrenaline and acetylcholine stimulated cAMP and cGMP production respectively but glutamate and gamma-aminobutyric acid stimulated production of both cyclic nucleotides.     

The influence of antistine on glycogenolytic effect of some biogenic amines in rat brain slices

Résumé On a démontré que l'antistine empêche in vitro l'effet glycogénolytique de l'histamine, bien qu'elle n'ait pas d'influence sur les actions glycogénolytiques de la noradrénaline, de la dopamine, de la sérotonine, du 3, 5-AMP cyclique et de son dérivé dibutirique. Ces résultats suggèrent l'existence de récepteurs particuliers pour les amines biogénique dans le tissue du cortex, du nucleus caudatus et du thalamus. De ces résultats on a conclu que, dans le cerveau du rat, l'adénocyclase pourrait être le récepteur histaminique.     

Somatostatin inhibits in vitro release of luteinizing hormone releasing hormone from rat mediobasal hypothalamic slices

Summary Somatostatin, in concentrations ranging from 10^–10 M to 10^–7 M, induces a dose-dependent inhibition of LHRH release from mediobasal hypothalamic slices incubated in vitro. In contrast, VIP, secretin, glucagon, substance P, neurotensin and arginine-vasotocin do not affect spontaneous release of LHRH.     

The effect of 5-hydroxytryptophan on the efflux of noradrenaline from brain slices

Zusammenfassung 5-Hydroxytryptophan erniedrigt die Konzentration von Noradrenalin in Hirnschnitten, sofern diese das Amin zuvor aus zugesetzteml-DOPA selber synthetisierten. Dieser Effekt beruht vermutlich darauf, dass 5-Hydroxytryptophan die Decaroxylierung desl-DOPA, das im Hirngewebe gespeichert wird, kompetitiv hemmt. Die Relation der Noradrenalin- und Serotoninkonzentration im Hirngewebe kann somit auch durch ein verändertes Angebot an Aminosäuren gestört werden.     

Absence of phosphogluconate pathway activity in normal and in ethanol-intoxicated slices from rat brain

Résumé L'auteur a repris la question de l'existence d'une voie oxydative fonctionnelle directe pour la glucose dans le cerveau adulte et constaté qu'elle ne peut être décelée ni dans des conditions normales ni lors d'une intoxication du sujet par l'étanol.     

Regional distribution of adenine nucleotides,glycogen, glucose and lactate in the adult rat brain

Résumé Le cervelet contient des quantités plus grandes d'ATP, d'ADP et de nucléotides totaux que le lobe frontal du cerveau ou la moelle cervicale. Ces différences ne sont pas trouvées avec l'AMP. Le contenu en glycogène, en glucose et en lactate est plus grand dans la moelle cervicale que dans le cervelet et dans le lobe frontal.

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We wish to thank Dr.H. Rehkämper from Boehringer Mannheim GmbH, who kindly supplied us with all the enzymes, substrates and cofactors.     

Adenylate cyclase and phosphodiesterase from brain tissue: Different stabilities during incubation of cerebral cortical slices

Summary Adenylate cyclase and phosphodiesterase were prepared from brain slices from guinea-pig. The specific acitivity of adenylate cyclase declined rapidly with increasing incubation time of tissue slices, while phosphodiesterase activity was almost uneffected by the incubation of brain slices.     

The influence of propranolol and dibenzyline on glycogenolytic effects of some biogenic amines in rat brain slices

Résumé On montre que le propranolol empêche les effets glycogénolytiques de la noradrénaline et de la dopamine, bien qu'il n'ait pas d'effet sur les actions glycogénolytiques de l'histamine, de la sérotonine, du 3,5-AMP cyclique et de son dérivé dibutyrique. On en conclu qu'au niveau du cervau des rats l'effet glycogénolytique des catécholamines résulte de l'excitation des récepteurs adrénergiques et que les autres unités régulatrices les adénylcyclases sont responsables des effets de l'histamine et de la sérotonine.     

Effects of hypo and hyperosmotic media on rabbit renal cortical slices

Summary Rabbit kidney cortex slices behave as osmometers when withstanding either hyperosmotic shocks or hypoosmotic shocks of amplitude up to P₁/P₂=1.25. For hypo-osmotic shocks of amplitude larger or equal to P₁/P₂=1.5 a volume regulation process occurs. Na⁺ is the main osmotic effector implicated in volume control.This work has been aided by a grant 1.5.422.82F from the FNRS to R.G. We wish to thank Mr J.M. Theate for his skilful assistance.     

Adenylate cyclase and phosphodiesterase from brain tissue: different stabilities during incubation of cerebral cortical slices.

Adenylate cyclase and phosphodiesterase were prepared from brain slices from guinea-pig. The specific activity of adenylate cyclase declined rapidly with increasing incubation time of tissue slices, while phosphodiesterase activity was almost uneffected by the incubation of brain slices.     

A depolymerizing effect of the luteinizing hormone and follicle stimulating hormone on the neurotubules of the hypothalamus-hypophysial tract in the rat

Résumé Les neurotubules des fibres nerveuses du tract hypothalamo-hypophysaire du rat sont désorganisées après des traitments in vitro avec l'hormone lutéinisante et l'hormone folliculaire stimulante. Le méchanisme de dépolymérisation est discuté.     

Cysteine-induced effect on amino acids in neonatal rat brain

Summary In neonatal rat brain 6 h after s.c. administration of L-cysteine, an increase was observed in most of the amino acids with the exception of glutamic acid, aspartic acid, phenylalanine, sarcosine, glutamine, hydroxyproline and phosphoethanolamine compared to age-matched saline controls. Cysteine was not present at detectable levels in control brain but was found to be 0.38 to 0.52 mole/g of fresh brain tissue in 2- and 4-day-old rats respectively after cysteine treatment.     

Adrenocorticotrophic hormone and cyclic adenosine monophosphate effect on mouse adrenal cortical cell membrane potential

Summary Adrenocorticotrophic hormone (ACTH) and cyclic adenosine monophosphate (cAMP) both caused a rapid and transient depolarization of the resting membrane potential of superfused rat adrenal cortical cells. The membrane depolarization to both secretagogues were very similar. The membrane potential changes occurred as early as 0.1 min and were dose dependent in both onset and extent of depolarization.The author gratefully acknowledges the generous financial support of the E.G. Schlieder Educational Foundation, the American Heart Association of Louisiana and the American Heart Association.     

Adrenocorticotrophic hormone and cyclic adenosine monophosphate effect on mouse adrenal cortical cell membrane potential

Adrenocorticotrophic hormone (ACTH) and cyclic adenosine monophosphate (cAMP) both caused a rapid and transient depolarization of the resulting membrane potential of superfused rat adrenal cortical cells. The membrane depolarization to both secretagogues were very similar. The membrane potential changes occurred as early as 0.1 min and were dose dependent in both onset and extent of depolarization.