Hypothermia induced in mice by enzyme-mediated depletion of serotonin

Summary Injection of a purified serotonin (and tryptophan)-degrading enzyme into mice produced a pronounced hypothermia when the mice were maintained at 22°C, but not at 30°C. Brain levels of serotonin and tryptophan were strikingly depleted, but concentrations of norepinephrine and dopamine remained unchanged.This investigation was supported by grants CA-18844 and CA-08748 awarded by the National Cancer Institute, DHEW. We thank Barbara Morelli and Margaret Costello for their technical assistance.     

Selective blockade by mephentermine of reserpine-induced serotonin depletion

Zusammenfassung Die kombinierte i.v. Verabreichung von Reserpin (1 mg/kg) und Mephentermin (1 mg/kg) bewirkte Erregung in Kaninchen. Diese Erregung ist verbunden mit einem Verlust an Noradrenalin (NE) im Gehirn, nicht jedoch mit einem Verlust an Serotonin (5-HT). Aus den Ergebnissen lässt sich schliessen, dass die beobachtete Erregung von einem momentanen Ungleichgewicht zwischen NE und 5-HT im Gehirn herrührt.

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This study is supported in part by Career Development Award No. K3 NB 15279-09 and Grant No. MH 11189 from the National Institutes of Health, U.S.P.H.S. The authors wish to thank Dr.A. J. Plummer of CIBA Pharmaceutical Company for supplying the reserpine phosphate and Dr.R. J. Bower of Wyeth Laboratories for the mephentermine used in this study.     

Adrenaline depletion induced by light in the dark-adapted retina

Resumen Una depleción inmediata de la adrenalina retiniana ocurre cuando sapos adaptados a la oscuridad son expuestos a una luz relativamente fuerte, alcanzándose un máximo en aproximadamente 5 min. La repleción de la adrenalina es más rápida cuando los animales, después de ser expuestos por 5 min a la luz, son devueltos a la oscuridad. En un período de 24 h la adrenalina alcanzó aproximadamente 85% de su valor original. Por otra parte, cuando los animales se mantienen expuestos a la luz, la repleción es más lenta y la adrenalina retiniana alcanza un máximo de sólamente 65% de su valor original en adaptación a la oscuridad.     

Kinetics of increased vascular permeability induced in rat skin by serotonin

Résumé Les auteurs ont étudié la cinétique du passage des complexes protein-colorant à travers les capillaires cutanés dont la perméabilité a été augmentée par l'injection préalable de serotonin dans la peau. Les résultats obtenus ont permis d'établir les lois qui règlent cette cinétique et le rôle des recepteurs adrénergic dans le phenomen inflammatoire.     

Role of serotonin in the diffuse inhibitory controls induced by nociceptive stimulation

In the anaesthetized Rat, the entire population of dorsal horn convergent neurones is differentially affected by a noxious stimulus: while exciting the segmental pool, it strongly inhibits the remaining population. The inhibitory effects, which involve supraspinal mechanisms, are reduced to a great extent in parachlorophenylalanine pretreated animals. The role of raphé-spinal serotonergic pathways in nociception is discussed.     

Modification by levo-propranolol of tremors induced by harmine in mice

It has been recently reported that the levo isomer of propranolol possesses anti-serotonin properties in animals. Since harmine-induced behavioural changes in mice are reported to be mediated through central serotonergic receptors, an attempt was made to test whether 1-propranolol would also modify harmine-induced responses by virtue of its anti-serotonergic or anti-adrenergic property. The results indicated that l- and dl-propranolol inhibited central serotonin receptor mediated responses to harmine in mice, a finding that is analogous to other recent observations.     

Modification by levo-propranolol of tremors induced by harmine in mice

Summary It has been recently reported that the levo isomer of propranolol possesses anti-serotonin properties in animals. Since harmine-induced behavioural changes in mice are reported to be mediated through central serotonergic receptors, an attempt was made to test whether 1-propranolol would also modify harmine-induced responses by virtue of its antiserotonergic or anti-adrenergic property. The results indicated that 1- and dl-propranolol inhibited central serotonin receptor mediated responses to harmine in mice, a finding that is analogous to other recent observations.     

Rate of depletion of noradrenaline in some peripheral tissues induced by a reserpine injection

Zusammenfassung Nor-Adrenalin (NA) verschwindet nach einer Reserpininjektion im Uterus des Kaninchens langsamer als in anderen Organen: nach 12 h noch Nachweis von Aminen in den vasomotorischen Uterusnerven, nicht aber zum Beispiel in derGl. submandibularis. Tendenz zu gleicher Reaktion zeigt der Uterus des Meerschweinchens, nicht aber der Ratte, der Maus oder des Hamsters. Es wird der Schluss gezogen, dass verschiedene sympathische Nervenendigungen gleicher Aufgabe variierende Grundeigenschaften zeigen.

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This study was aided by grant NB 02854-04 from the United States Public Health Service.     

Growth hormone resynthesis in the pituitary after depletion induced by a hypothalamic extract

Riassunto Lo studio della velocità di resintesi dell'ormone somatotropo nella ipofisi di ratto dopo la massiva deplezione indotta dalla somministrazione endocarotidea di un estratto di eminenza mediana dell'ipotalamo, ha messo in evidenza che 1 ora dopo la somministrazione il contenuto dell'ormone viene ricostituito in misura del 60%, 3 ore dopo sale all'80%, 5 ore dopo corrisponde ai valori normali.     

Immune-mediated glomerulonephritis induced by mercuric chloride in mice

Summary The BALB/c mouse developed mesangial deposits of immune constituents and light microscopical changes characteristic of immune complex glomerulonephritis after 8 weeks' treatment with mercuric chloride given by s.c. injection. There were no signs of linear of granular immune deposits along the glomerular capillary basement membrane after 2 or 8 weeks. The antigen could not be identified. No antibodies to nuclear or renal structures were found. Using a histochemical method (silver amplification) mercury was detected by light and electron microscopy in tubular and glomerular structures. Mercury was present in secondary lysosomes of the mesangial cells after eight weeks of mercury poisoning.We are deeply indebted to Dr. Gorm Danscher, Institute of Anatomy, B., University of Aarhus, Denmark, for valuable discussions and technical advice. This work was supported by the Swedish Medical Research Council, project no 6536.     

Forskolin supresses seizures induced by pentylenetrazol in mice

Summary Forskolin, an adenylate cyclase activator when injected s.c. (1 mg/kg) in mice, caused an elevation of cAMP in the forebrain and cerebellum of up to 170% and 130%, respectively. The treatment was found to prevent seizures induced by pentylenetetrazol. This suppression had subsided 30 min after the injection, when cAMP level was again normal in the cerebellum but still elevated in the forebrain.     

Forskolin suppresses seizures induced by pentylenetetrazol in mice

Forskolin, an adenylate cyclase activator when injected s.c. (1 mg/kg) in mice, caused an elevation of cAMP in the forebrain and cerebellum of up to 170% and 130%, respectively. The treatment was found to prevent seizures induced by pentylenetetrazol. This suppression had subsided 30 min after the injection, when cAMP level was again normal in the cerebellum but still elevated in the forebrain.