Habituation to iterative photostimulation in the palmar skin conductance response of mice,its delay by psychoanaleptics

Summary In mice, iterative photostimulation results in habituation, detected in the palmar skin conductance response. Psychoanaleptics delay this habituation in proportion to the dose administered.     

The potent tremorgenic neurotoxins lolitrem B and aflatrem: a comparison of the tremor response in mice

Tremor dose-response curves were determined for mice dosed with the ryegrass neurotoxin lolitrem B, and the tremor-genic mycotoxin aflatrem. A family of characteristic curves was revealed for each tremorgenic, with lolitrem B eliciting a sustained tremor response persisting for over 24 h.     

The potent tremorgenic neurotoxins lolitrem B and aflatrem: A comparison of the tremor response in mice

Summary Tremor dose-response curves were determined for mice dosed with the ryegrass neurotoxin lolitrem B, and the tremorgenic mycotoxin aflatrem. A family of characteristic curves was revealed for each tremorgen, with lolitrem B eliciting a sustained tremor response persisting for over 24 h.     

Effects of some GABAergic agents on quinine-induced seizures in mice

The effects of some GABAergic agents on seizures induced by quinine were studied in mice. Muscimol, AOAA, DABA and baclofen significantly protected mice against quinine-induced convulsions. Bicuculline effectively enhanced quinine-induced convulsions, and significantly attenuated the protective effects of muscimol, AOAA and DABA against convulsions induced by quinine. Diazepam and phenobarbitone significantly protected mice against convulsions induced by quinine. However, phenytoin did not affect quinine-induced seizures to any significant degree. These results indicate that the convulsant effect of quinine may be due to a disturbance in the status of the GABAergic system.     

The effects of chronic alcohol ingestion in mice on contractile properties of cardiac and skeletal muscle: a comparison with normal and dehydrated-malnourished controls.

In vitro isometric contractile tension was measured in heart and skeletal muscle in 3 groups of mice: 1. a control group, 2. a group maintained for 27 weeks on 20% alcohol, and 3. a group whose fluid intake was restricted to the extent equaling that which occurred in the alcohol treated animals. Results showed a reduction in cardiac twitch tension in both the alcohol and fluid restricted group, as compared to normal controls. We therefore consider that dehydration per se may play an important role in the etiology of alcoholic cardiomyopathy.     

Effects of some GABAergic agents on quinine-induced seizures in mice.

The effects of some GABAergic agents on seizures induced by quinine were studied in mice. Muscimol, AOAA, DABA and baclofen significantly protected mice against quinine-induced convulsions. Bicuculline effectively enhanced quinine-induced convulsions, and significantly attenuated the protective effects of muscimol, AOAA and DABA against convulsions induced by quinine. Diazepam and phenobarbitone significantly protected mice against convulsions induced by quinine. However, phenytoin did not affect quinine-induced seizures to any significant degree. These results indicate that the convulsant effect of quinine may be due to a disturbance in the status of the GABAergic system.     

Mast cells,co-carcinogenesis and anti-carcinogenesis in the skin of mice

Zusammenfassung Wenn auf der Haut der Maus eine Karzinogenese mit minimalen Dosen eines reinen Initiators und eines reinen Promoters (Co-karzinogen) induziert wird, tritt eine Mastzellreaktion auf. Diese Reaktion erreicht ein Maximum unter den Papillomen. Sie kann durch Applikation eines Antikarzinogens verhindert werden.     

The acidic glycosaminoglycans in the skin of athyroid rats: the effects ofl-tri-iodothyronine

Resumen Este estudio demuestra que en piel de ratas atiroideas, en comparación con las normales, el ácido hialurónico aumenta un 20% mientras que el dermatán sulfato disminuye un 28%, no encontrándose diferencias significativas en las demás fracciones de glycosaminoglycanos. Este efecto diferencial es similar al ya encontrado por nosotros en cartílago.

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This work was partially supported by the Consejo Nacional de Investigaciones Cientificas y Técnicas de la República argentina.

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Member of the Carrera del Investigador Científico del C.N.I.C.T. de la Argentina.     

The effect of abrin,anti-lymphocyte globulin and their conjugates on the immune response of mice to sheep red blood cells

Summary A chemical conjugate of anti-mouse lymphocyte globulin and abrin, is about twice as effective as a similar conjugate made with normal immunoglobulin and abrin, in suppressing the ability of the mouse to respond immunologically to an injection of sheep red blood cells.Acknowledgment. We thank Dr Stuart, Society of Herbalists, London, and Prof. G.C. Clark, Dept. of Botany, University of Ghana, for gifts ofAbrus precatorius seeds, and Mrs L. Bushby for help in the preparation of the horse anti-mouse lymphocyte globulin. D.C.E. is an external member of the staff of the Wellcome Foundation Ltd.     

The involvement of noradrenaline, 5-hydroxytryptamine and acetylcholine in imipramine-induced seizures in mice

The influence of some noradrenergic, 5-hydroxytryptaminergic and cholinergic agents on imipramine-induced seizures were investigated in mice. DL-threo-3,4-dihydroxyphenylserine (DOPS) and pargyline significantly potentiated imipramine-induced seizures. Phentolamine and prazosin significantly attenuated seizures elicited by imipramine and significantly attenuated the seizure-enhancing effect of DOPS. -Methyl-p-tyrosine and reserpine significantly attenuated seizures induced by imipramine. Disulfiram significantly protected mice against imipramine-induced seizures. However, DOPS significantly potentiated seizures induced by imipramine in disulfiram-pretreated animals. Clonidine effectively protected mice against imipramine-induced seizures. Idazoxan, on the other hand, significantly protentiatied seizures induced by imipramine and significantly antagonised the protective effect of clonidine against the seizures. 5-HTP, PCPA, cyproheptadine, mianserin, ketanserin and trazodone did not affect imipramine-induced seizures to any significant extent. Physostigmine antagonised seizures induced by imipramine while atropine significantly potentiated the seizures, and significantly attenuated the protective effect of physostigmine against the seizures. These data suggest that enhancement and attenuation of central noradrenergic and cholinergic neurotransmissions respectively, and not 5-HT mechanisms, may underlie imipramine-induced seizures in mice.     

Mast cells in the skin of normal,hairless and athymic mice

Summary The skin of congenitally athymicnu/nu mice is rich in mast cells which stain metachromatically, contain histamine and 5-hydroxytryptamine, and participate in the PCA reaction. Mast cells of athymic mice have thus the attributes of normal mast cells.This work was supported by grants from the Swiss National Science Foundation (No. 3.516.71 and 3.234.74) and the Fritz Hoffmann-La-Roche-Stiftung.The skilful technical assistance of MissR. Keist is gratefully acknowledged.     

Studies on phytohemagglutinins XV. Hemagglutinins of the pea and the lentil: Advantage of their application in comparison to concanavalin a in some agglutination reactions

Zusammenfassung Phythämagglutinine der Erbse und Linse besitzen ähnliche biologische Eigenschaften wie Concanavalin A; ihre Aktivität ist jedoch in allen Agglutinationsreaktionen grösser als die von Concanavalin A.