Histamine as an extremely potent releaser of vasopressin in the rat.

Intraperitoneal and intraventricualr injection of histamine induces a very fast and high elevation of vasopressin in rat plasma as determined by radioimmunoassay. The effects are dose and time related. The intraventricular injection is more effective with regard to time and dose than the intraperitoneal injection.     

Visualization of opiate receptors in the locus coeruleus of rats: high resolution radioautography after administration of a tritiated met-enkephalin analog]

Opiate receptor sites were visualized by high resolution radioautography in the locus coeruleus of the Rat following intraventricular injection of the met-enkephalin analogue FK 33-824 tritiated with a high specific activity (3H-FK). After administration of a tracer dose of 3H-FK, more than 75% of the radioactivity detected in the locus coeruleus is specifically bound to opiate receptor sites. These are distributed both between and inside neuronal perikarya. After administration of 3H-FK at high concentration, electron microscope radioautography shows the presence of specific opiate binding sites at the level of axo-somatic and axo-dendritic synaptic junctions. These synaptic binding sites could correspond to receptor sites for endogenous enkephalins.     

A rapid method for the verification of drug injection into the cerebral ventricular system of the rat

Summary A precise method for the injection of drugs into the cerebroventricular system of small animals used for experimentation is described. This method, based on the intraventricular pressure record, gives absolute certainty for the injection of a drug into a previously selected site and thus avoids the subsequent histological studies.     

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.     

Über die amindepletierende Wirkung verschiedener Digitaliskörper,ein Beitrag zur Aufklärung des Wirkungsmechanismus der Herzglykoside

Summary After i.v. injection of g-strophanthin, convallatoxin, digitoxin, digitoxigenin, digoxin and proscillaridin, dependent on the dose and time of application, we found a significant decrease of noradrenalin in the hearts of rats (about 50%).     

Variation in delayed hypersensitivity to methylated bovine serum albumin as as function of the dose and time of administration of cyclophosphamide]

The injection of Cy before immunization provokes an intensification of delayed-type hypersensitivity (DTH) to methylated bovine serum albumin (M-BSA) and a diminution of about 90% of the cell number in various lymphoid tissues. The relationship between these observations, the time of administration, the dose of injected Cy and the intensity of DTH reactions, allows us to formulate hypotheses concerning the physiological modulation of DTH.     

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.     

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.     

Time-dependence of estradiol effects on protein synthesis in the rat neurohypophysis.

The incorporation of 3H-leucine into neurohypophyseal proteins was measured in vitro, 24 h after the administration of a single dose of estradiol (0.3 mug) to castrated female rats. Estradiol treatment caused a significant increase of 3H-leucine incorporation into proteins of the posterior lobe. The effects of estradiol depended largely upon time injection. Rats injected at 06.00 h, i.e., at the end of the dark period exhibited a 74% increase in protein synthesis, whereas rat injected at 14.00 h, i.e., at the middle of the light period only showed a 30% of increase.     

Thrombozytose und Eosinopenie bei Ratten nach einmaliger 5-Oxytryptamininjektion

Summary After injection of a high dose of 5-hydroxytryptamine into rats, the blood reveals a strong increase of the blood platelets and a definite decrease of the eosinophiles. The maxima of increase and decrease are in temporal accordance.     

Irradiation of the head by 60Co opens the blood-brain barrier for drugs in rats

The passage of 6 model drugs; acetylsalicylic acid, chloramphenicol, ethimizol, carbisocaine, heptacaine, and diazepam, through the blood-brain barrier, was determined in unirradiated control rats and in animals 1, 3, and 7 days after irradiation of the head only with a dose of 25 Gy from a 60Co source. The brain uptake index (BUI), which compares the uptake of the test substance with that of 3H2O 5 s after their injection into the common carotid artery, was significantly increased in comparison with unirradiated controls 7 days after irradiation, for all substances tested except for ethimizol. For acetylsalicylic acid and chloramphenicol it was also significantly increased in the other time intervals. The less lipophilic substances showed a greater relative increase of BUI than the more lipophilic ones.     

Fehlende immunogene Wirkung exogenen Insulins bei Hunden nach langsamer Adaptation an Insulin

Summary Subcutaneous injection of exogenous insulin always results in a production of antibodies against insulin. But after a slowly increased dose of insulin (a daily end dose of 3.5–4.2 U/kg) insulin antibodies could not be found in the serum of 2 dogs. This failure of immunogenic action of insulin is discussed as an induction of immunotolerance by the modus of initial antigen application.     

Nachweis von3H-Digitoxin in der Herzmuskelzelle

Summary In autoradiographs of intraventricular muscle bundles of beef heart, tritiated digitoxine is found outside the membrane and inside the muscle cell at the moment of maximal inotropic action.     

Cannabidiol and cannabinol in man

Résumé Le cannabidiol administré à dose de 100 mg par os et de 30 mg par injection i.v. fut inactif dans les sujets d'étude. Le cannabinol, à dose orale de 400 mg, le fut aussi. Ces constituants du cannabis ne contribuent donc pas à l'effet pharmacologique.     

Thrombozytose und Eosinophilie bei adrenalektomierten Ratten nach einmaliger 5-Hydroxytryptamininjektion

Summary In adrenalectomized rats, the injection of a single high dose of 5-hydroxytryptamin results, as in intact animals previously reported, in a strong increase of the number of platelets in the peripheral blood. The number of eosinophils, instead of decreasing, also rises. The maxima of increase are not in temporal accordance.     

Habituation failure of skin conductance response after intraventricular administration of 6-hydroxydopamine in cats

Summary The effects of intraventricular administration of 6-hydroxydopamine on electrodermal activity were studied in cats. The treatment slowed down or eliminated habituation of the skin conductance response to repeated auditory stimuli. However, the impairment of habituation was not accompanied by an increase in the rate of spontaneous skin conductance fluctuation.     

Habituation failure of skin conductance response after intraventricular administration of 6-hydroxydopamine in cats

The effects of intraventricular administration of 6-hydroxydopamine on electrodermal activity were studied in cats. The treatment slowed down or eliminated habituation of the skin conductance response to repeated auditory stimuli. However, the impairment of habituation was not accompanied by an increase in the rate of spontaneous skin conductance fluctuation.     

Irradiation of the head by60Co opens the blood-brain barrier for drugs in rats

Summary The passage of 6 model drugs; acetylsalicylic acid, chloramphenicol, ethimizol, carbisocaine, heptacaine, and diazepam, through the blood-brain barrier, was determined in unirradiated control rats and in animals 1, 3, and 7 days after irradiation of the head only with a dose of 25 Gy from a⁶⁰Co source. The brain uptake index (BUI), which compares the uptake of the test substance with that of³H₂O 5 s after their injection into the common carotid artery, was significantly increased in comparison with unirradiated controls 7 days after irradiation, for all substances tested except for ethimizol. For acetylsalicylic acid and chloramphenicol it was also significantly increased in the other time intervals. The less lipophilic substances showed a greater relative increase of BUI than the more lipophilic ones.     

Effects of thyrotrophic-releasing hormone (TRH) on thermoregulation in the rat

At ambient temperatures (Ta) of both 8 and 22 degrees C, intraventricular administration of TRH (10-80 microgram) produced a dose-dependent hypothermia in rats. The hypothermia was due to both decreased metabolic heat production and cutaneous vasodilatation. In contrast, at 30 degrees C Ta, TRH increased metabolic heat production (due to behavioral excitation) and led to hyperthermia.     

Host immune rejection of TA3 ascites carcinoma cells following administration of a water soluble carbodiimide.

Regression of TA3 ascites carcinoma tumors occurred following i.p. injection of 1-ethyl-3-(3'-dimethylaminopropyl)carbodiimide-HC1. An immunological mechanism of drug action was indicated by the fact that no significant antitumor activity was demonstrable in mice that had previously received an immunosuppressive 700 rad dose of 60Co radiation.