Reversible lenticular opacities induced in rats by emotional stress

Zusammenfassung Ratten (20 Tiere, 45 Tage alt) erhielten 150 mg/kg paraglynes Hydrochlorid s.c. injiziert. Akustischer Schock (2 h später) ergab bei 16 von 20 Tieren eine reversible subkapsuläre Linsentrübung.

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The authors wish to thank Mr. R. D.Lock for technical assistance.     

Vasotocin protects rats against convulsions induced by pentylenetetrazol

Summary The AVP analog, vasotocin, administered s. c. effectively antagonized pentylenetetrazol-induced convulsions, supporting the contention that AVP may be a mediator in convulsive disorders.This work was supported by the Medical Research Council of Canada.     

T-cell leukemia induced by 1-propyl-1-nitrosourea in Fischer rats

Summary T-cell leukemia was induced at a high rate in female Fischer rats by continuous oral administration of 1-propyl-1-nitrosourea. No association of oncorna viruses were found in the leukemogenesis.The authors are greatly indebted to Professor K. Yokoro of the Department of Pathology, Research Institute for Nuclear Medicine & Biology, for his valuable suggestions. This work was supported in part by a Grant-in-Aid for Cancer Research from the Ministry of Education, Science and Culture, Japan.     

An escape phenomenon from water and sodium retention induced by propranolol in rats

Rats given a daily dose of propranolol 45 mg/kg b.wt retain water and sodium for 4 days, escaping during the 5th and 6th days in which their excretions are larger than basal values. Afterwards, in the period studied, they make a new retention and clearing is less accentuated. No relationship could be found between these retentions and plasma renin activity or renal renin content.     

An escape phenomenon from water and sodium retention induced by propranolol in rats

Summary Rats given a daily dose of propranolol 45 mg/kg b.wt retain water and sodium for 4 days, escaping during the 5th and 6th days in which their excretions are larger than basal values. Afterwards, in the period studied, they make a new retention and clearing is less accentuated. No relationship could be found between these retentions and plasma renin activity or renal renin content.Acknowledgments. The authors thank Mrs Inmaculada Millás for excellent technical assistance and Maria Isabel Navajos for secretarial help.     

Asymmetry of turning behaviour of rats induced by amphetamine and apomorphine

Summary Turning behaviour of rats following injection of amphetamine is in the same direction as following apomorphine. Unilateral common carotid artery ligation does not affect this asymmetry. Thus the reason for the asymmetry in turning behaviour following injection of amphetamine is probably due to postsynaptic dopaminergic asymmetry within the corpus striatum.     

Eating and drinking induced by cerebral-ventricular injections in rats with lesions in the lateral hypothalamus

Résumé Par des lésions bilatérales hypothalamiques on a rendu des rats aphagiques et adipsiques. Durant la période de convalescence, on a injecté dans le ventricule latéral du pentotal de sodium (ce qui normalement fait manger les animaux) et une solution saline hypertonique (qui normalement les fait boire). On a trouvé qu'après les lésions les rats ne réagissent que lorsqu'ils sont redevenus capables de manger et de boire spontanément.

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This work was supported in part by a grant from the National Institute of Neurological Diseases and Blindness, No. NB 01941, of the National Institutes of Health, U.S. Public Health Service, Bethesda, Maryland; by a grant from the National Science Foundation, No. GB-4594, Washington, D.C.; and the Fund for Research and Teaching of the Department of Nutrition, Harvard School of Public Health, Boston, Massachusetts.     

Vitamin B12 amplifies circadian phase shifts induced by a light pulse in rats

Vitamin B₁₂ (VB₁₂) is a putative modulator of the human circadian clock, improving entrainability to the 24 h light-dark cycle. The present study was intended to elucidate the mechanism of VB₁₂ action in an animal model. In male rats free-running under constant dim illumination, a single light pulse of 50–1000 lux for 20 min given at circadian time (CT) 20 induced a 0.28 to 1.08 h phase advance and at CT 14 induced a 0.54 to 2.10 h phase delay. A 3 h intracerebroventricular (icv) infusion of 30 nmol VB₁₂ starting 2 h prior to a 20 min 200 lux light pulse significantly amplified phase shifts in comparison with saline-treated or untreated controls. The mean phase advance (1.13 h) was 1.8-fold greater than that of saline-infused controls, whereas the mean phase delay (2.28 h) was 2.9-fold greater. These values were comparable to the maximal phase shifts caused by 1000 lux light pulses in untreated rats. Since the same VB₁₂ treatment alone had failed to induce a phase shift in a previous experiment, these results indicate that VB₁₂ strongly enhanced light pulse-induced phase shifts and thus augmented the entrainability of the circadian clock to light.     

Aggressive behaviour induced by marihuana compounds and amphetamine in rats previously made dependent on morphine

Résumé Les rats soumis à la morphine ont été traités pendant la phase d'abstinence avec des injections i.p. d'amphéta mine et (–) ⁹-trans-tätrahydrocannabinol.

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With a fellowship from Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP). We are very grateful to Prof.J. Ribeiro do Valle, Escola Paulista de Medicina, for the generous supply of THC.