Myelin changes in the rats CNS following intraventricular injection of serum

Summary Normal human or rat serum administered by intraventricular injection induced demonstrable changes in the rat CNS myelin as seen from an increased recovery of dissociated myelin (DM), i.e. a myelin-related low density membrane fragments, from the tissue homogenates. The yield of DM reached a maximum on the third postinjection day and returned to the control level by day 5. In spite of the increased recovery of DM, no physico-chemical alternations in myelin isolates and no histological abnormalities in the tissue could be detected. The production of DM seems to be a sensitive index of serum-induced alteration of the myelin sheath.Acknowledgments. The authors thank J. Mellach and P. Salinas for their skillful technical assistance. The study was supported by the Danish Multiple Sclerosis Society.     

Myelin changes in the rats CNS following intraventricular injection of serum

Normal human or rat serum administered by intraventricular injection induced demonstrable changes in the rat CNS myelin as seen from an increased recovery of dissociated myelin (DM), i.e. a myelin-related low density membrane fragments, from the tissue homogenates. The yield of DM reached a maximum on the third postinjection day and returned to the control level by day 5. In spite of the increased recovery of DM, no physico-chemical alternations in myelin isolates and no histological abnormalities in the tissue could be detected. The production of DM seems to be a sensitive index of serum-induced alteration of the myelin sheath.     

Insomnia induced by P-chlorophenylalanine in cats. Its reversibility by intraventricular injections of indolamines

Intraventricular injection of 250 microgram of 5 HTP induces both slow wave and paradoxical sleep, after 20-60 min. latencies, in insomniac Cats pretreated with P-chlorophenylalanine. Direct injections of 5 HTP in several brain stem structures do not induce sleep. The long latency or paradoxical sleep induction and its suppression with chloramphenicol suggest that indolamines are not directly responsible for paradoxical sleep, but that they act by controlling the synthesis and/or the liberation in the periventricular system of some specific paradoxical sleep inducing factor.     

Diurnal variations in thermoregulatory responses to intrahypothalamic and intravenous injections of noradrenaline in the pigeon

Summary The differences in responses of T_b, T_f and both to intrahypothalamic and i.v. administration of NA were measured both at noon and at midnight in the pigeon. Although the T_b and were at a higher level in the daytime, no differences in the magnitude of the fall in and T_b were obtained after either intrahypothalamic or i.v. injections of NA, whether it was measured during the day or at night. The only marked difference was the more prominent vasodilatation in the daytime after both routes of injection.     

Experimental hydrocephalus following mechanical increment of intraventricular pulse pressure

Summary Experimental hydrocephalus has been induced in lambs by artificial increase of the amplitude of intraventricular cerebrospinal fluid (CSF) oscillations related to arterial pulsations, without concominant changes of the mean CSF-pressure. The characteristics of this hydrocephalus demonstrate that the intraventricular CSF-pulsations can play a role in the genesis of ventricular dilatation. Such a method may be used to produce an original model of hydrocephalus independent of changes of CSF-circulation or absorption.This work was supported by grant of CNR.     

Inhibitor interneurons of horizontal ocular saccades studied in the alert cat with the aid of intra-axonal injections of peroxidase

A simultaneous study of the functional and morphological characteristics of burst inhibitory neurons (B.I.N.) has been performed in the alert cat. For the first time, in the central nervous system of mammal, extra- and intracellular records have been coupled with intra-axonal injection of H.R.P. in the alert animal. The B.I.N. discharge during saccades and the quick phase of vestibular and optokinetic nystagmus oriented toward the ipsilateral side of recording. The frequency of discharges is proportional to the eye angular velocity. The axons end on the abducens motoneuron. Collaterals reach the controlateral prepositus hypoglossi nucleus, medial vestibular nucleus and reticular nuclei.     

Extraprimary cortical evoked potentials in freely moving cat following photic stimulation

Zusammenfassung Die extraprimären optischen Potentiale, die in der somatosensorischen, akustischen und Assoziationsrinde der wachen Katzen mittels chronischer epiduraler Elektroden registriert wurden, zeigen fast dieselbe Latenz wie die primären Potentiale, unterscheiden sich aber von ihnen durch ihre Form.     

Insulin-induced enhancement of anaphylactoid reaction to a non-carbohydrate antigen

Résumé Nous avons constaté que chez les souris l'insuline possède une sensibilité élevée au peptone anaphylactoïde non-carbohydraté. Ce résultat concorde avec l'hypothèse d'une relation inverse entre la quantité de glucose dans le sang et la sensibilité d'un hôte à une grande variété de «stressors».     

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation, in the cat

The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.     

The role of the substantia nigra on the rage reaction elicited by hypothalamic stimulation,in the cat

Summary The effects of substantia nigra stimulation on the rage reaction evoked by hypothalamic activation were studied. The reference value of the rage reaction was the latency of the hissing, which was constant in all animals when hypothalamic stimulation was performed with the same parameters. Simultaneous activation of substantia nigra and hypothalamus determined a significant decrease in hissing latency. The influence of the substantia nigra on the affective components of the aggressive behavior is underlined.This work was supported by a grant from the Consiglio Nazionale delle Ricerche Roma, Italy.