Blocking by picrotoxin of nigra-evoked inhibition of neurons of ventromedial nucleus of the thalamus

Summary The transmitter substance released by nigro-thalamic fibres is proposed to be -aminobutyric acid, since picrotoxin blocked nigra-evoked monosynaptic inhibition of thalamic neurons.Supported by grants Nos 212009 and 311410 from Ministry of Education of Japan.The authors wish to thank Dr Marjorie Anderson, University of Washington, Seattle, for improving the English.     

Presynaptic and postsynaptic inhibition on transmission of cutaneous afferent volleys through the cuneate nucleus during sleep

Riassunto Durante i movimenti rapidi oculari caratteristici della fase desincronizzata di sonno si osserva una depressione fasica della risposta lemniscale alla stimolazione di fibre cutanée. Questa modulazione ipnica della risposta lemniscale è dovuta a meccanismi di inibizione presinaptica e postsinaptica.     

Histochemical localization of glutamic acid dehydrogenase activity in the cuneate nucleus of the cat1

Summary Glutamic acid dehydrogenase activity was observed both in the neuropil as well as in several classes of cuneate neurons in the cat.The excellent technical assistance of Mr. C. T. Lee of our Histology Laboratory, and the support and encouragement of Professor W. C. Wong, Anatomy Department, are gratefully acknowledged.     

Comparison of the effects of different isomers of bicuculline infused in the preoptic area on male rat sexual behavior

Summary Intracerebral infusion of (+) bicuculline methiodide, but not of its (–) isomer, in the preoptic area, stimulated masculine sexual behavior in rat as evidenced by a decrease in the number of intromissions preceding ejaculation and a shortening of the ejaculation latency and postejaculatory interval. Data suggest a role of the GABAergic system in mediating masculine sexual behavior.Acknowledgments. Authors wish to thank Ms Elisabeth Wallin for excellent technical assistance and Ms Madelene Kröning for preparing the figures.     

Comparison of the effects of different isomers of bicuculline infused in the preoptic area on male rat sexual behavior

Intracerebral infusion of (+) bicuculline methiodide, but not of its (-) isomer, in the preoptic area, stimulated masculine sexual behavior in rat as evidenced by a decrease in the number of intromissions preceding ejaculation and a shortening of the ejaculation latency and postejaculatory interval. Data suggest a role of the GABAergic system in mediating masculine sexual behavior.     

Beta-adrenergic blocking agents as potent antagonists of mescaline-induced contractions in the rat uterus

Summary In the isolated rat uterus, mescaline induces contractions that are notably antagonized by catecholamines, by -adrenergic stimulants and certain -adrenergic blocking agents as well as by chlorpromazine, amitriptyline and methysergide.     

Beta-adrenergic blocking agents as potent antagonists of mescaline-induced contractions in the rat uterus.

In the isolated rat uterus, mescaline induces contractions that are notably antagonized by catecholamines, by beta-adrenergic stimulants and certain beta-adrenergic blocking agents as well as by chlorpromazine, amitriptyline and methysergide.     

Role of the Raphe Magnus nucleus in morphine analgesia : studies with intracerebral microinjections in the rat]

Microinjections of low concentration of morphine (5 micrograms) into the nucleus Raphé Magnus of the Rat produce a strong analgesia that can be reversed by systemic naloxone, an opiate antagonist. The administration of naloxone (5 micrograms) into the Raphé Magnus considerably reduces the effects of intravenous morphine. The effects of microinjections of morphine are strongly reduced by Cinanserin, suggesting a role for serotoninergic mechanisms in morphine analgesia.     

Alkylating esters VII. The metabolism of iso-propyl methanesulphonate and iso-propyl iodide in the rat

Zusammenfassung Nachweis, dass die im Rattenharn auftretenden Metaboliten Isopropyljodid und Isopropylmethansulfonat für einen unterschiedlichen Wirkungsmechanismus der Substanzen in vivo sprechen. Aus Isopropylmethansulfonat entsteht durch einen monomolekularen Prozess das äusserst reactive Dimethylcarboniumion, während Isopropyljodid aufgrund einer bimolekularen Reaktion haupsächlich durch Hydrolyse entgiftet wird.     

Projections from nucleus accumbens to globus pallidus and substantia nigra in the rat

Summary Stimulation of nucleus accumbens produces inhibition and facilitation of neuronal activity in the ipsilateral globus pallidus and substantia nigra. Small lesions in the accumbens reduce pallidal but not nigral GABA content.Acknowledgment. This work was supported by an MRC grant to Prof. D. W. Straughan.     

Projections from nucleus accumbens to globus pallidus and substantia nigra in the rat

Stimulation of nucleus accumbens produces inhibition and facilitation of neuronal activity in the ipsilateral globus pallidus and substantia nigra. Small lesions in the accumbens reduce pallidal but not nigral GABA content.     

An ultrastructural study of the synaptic glomeruli in the intermediolateral nucleus of the rat

Résumé On a constaté que le neuroptile du noyau intermédio-latéral du rat contient de nombreux glomérules synaptiques gliaux encapsulés dans lesquels se trouve habituellement un dentrite ou axe terminal très visible surmonté par de petits boutons et des dentrites. Les glomérules sont accompagnés de synapses axo-axonaux qui peuvent être le corrolaire structural d'une inhibition présynaptique. La signification fonctionnelle des glomérules et des synapses axo-axonaux est discutée.

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It is a pleasure to acknowledge the technical assistance of Mr.H. L. Chan.     

Possible existence of a presynaptic positive feedback mechanism enhancing dopamine transmission in the anterior cingulate cortex of the rat

A series of microiontophoretic and VTA stimulation experiments, conducted in intact, GBR-12909-treated, alpha-methylparatyrosine-depleted or 6-hydroxydopamine-denervated rats, provide suggestive evidence for the existence of a presynaptic, positive feedback mechanism triggered by dopamine reuptake and favoring the release of this transmitter in the anterior cingulate cortex.     

Comparison of the effectiveness of intramuscular and intraperitoneal ACTH in the rat

Summary Injection of 1–24 ACTH is more effective by the i.m. than i.p. route. Large doses are required to induce consistent maximal adrenal corticosterone secretion.Supported by grants from the National Institute of Arthritis, Metabolism and Digestive Diseases, National Institutes of Health, Bethesda, Maryland, USA.