Shortened duration of drug-induced behavioral excitation in rats with septal lesions

Resumen En las ratas, la reacción elevada de la respuesta evasiva, después de darles iproniazida y tetrabenazina aparentemente está relacionada con el suelto acrecentado de acetylcholina en al parte frontal del cerebro. Cuando las ratas con lesiones septales recibieron estas dos drogas, sus periódos resultantes de excitacion de conducta eran significantamente mas cortos que los de los controles. Como las lesiones septales producen disminución en los niveles de la acetylcholina en el cerebro, estos datos implicaron más el sistema cholinergica en la excitación producida por la iproniziada-tetrabenazina.     

Hypersensitivity to endotoxin hepatotoxicity in rats with inflammatory lesions

Summary The ratio of sinusoidal nonparenchymal cells to hepatocytes in rat liver was significantly increased following induction of inflammation, and decreased after subsequent exposure to endotoxin, particularly in the region around the terminal portal venules. Rats with inflammatory lesions were more sensitive to endotoxin hepatocytotoxicity than normal controls, as judged from the dose-dependent increase in activity of serum transaminases and from the extent of liver tissue injury. In addition, these animals, which were already in a state of depletion of hepatic glycogen, demonstrated marked hyperglycemia 24 h after endotoxin administration in small doses of less than 2 mg/kg.     

Light-microscopic demonstration of drug-induced myelin bodies in the liver of rats

Zusammenfassung Sekundäre Lysosomen mit multilamellärer Myelinkörper-Struktur, die in der Rattenleber nach Behandlung mit verschiedenen Agenzien (z.B. Triparanol, Chloroquin, Mepacrin) induziert werden können, sind aufgrund ihrer Malteserkreuz-Konfiguration im polarisierten Licht lichtmikroskopisch nachweisbar. Mit fluoreszierenden Substanzen (Chloroquin, Mepacrin) zeigen die Malteserkreuz-Einschlüsse im Zytoplasma starke Fluoreszenz, was auf ihre Akkumulation in den Myelinkörpern hinweist. Nach längerer Behandlung treten Myelinkörper auch in zahlreichen andern Organen auf und induzieren unter anderem die Bildung von Schaumzellen in der Lunge.     

Hypersensitivity to endotoxin hepatotoxicity in rats with inflammatory lesions

The ratio of sinusoidal nonparenchymal cells to hepatocytes in rat liver was significantly increased following induction of inflammation, and decreased after subsequent exposure to endotoxin, particularly in the region around the terminal portal venules. Rats with inflammatory lesions were more sensitive to endotoxin hepatocytotoxicity than normal controls, as judged from the dose-dependent increase in activity of serum transaminases and from the extent of liver tissue injury. In addition, these animals, which were already in a state of depletion of hepatic glycogen, demonstrated marked hyperglycemia 24 h after endotoxin administration in small doses of less than 2 mg/kg.     

Effects of placental lesions on foetal growth in rats

Résumé Un état d'insuffisance placentaire a été produit chez la ratte au moyen de lésions électrolytiques effectuées au 17^e jour de gestation. Le poids corporel ainsi que le poids du foie des foetus, au 21^e jour de la grossesse, présentèrent une diminution; tandis que le poids du cerveau en relation à celui du foie avait augmenté. Ces résultats indiquent que les foetus ainsi traités subissent un retardement de croissance par rapport aux témoins de même âge.

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Acknowledgments. The author wishes to thank Dr.D. G. Montemurro for the use of the electrolytic apparatus and Mr.N. Falconer and Mr.J. Krcek for their technical assistance.     

Effect of brain lesions on hypothalamic noradrenalin in rats

Résumé Des lésions bilaterales, localisées par stéréotaxie dans la région de l'hippocampe chez le Rat, produisent au bout de 20 jours une diminution significative de la concentration en noradrénaline de l'hypothalamus. Si les rats sont sacrifiés 10 jours seulement après la lésion, il n'y a pas de modifications dans cette concentration. Le contenu en noradrénaline de l'hypothalamus est légèrement réduit par des lésions thalamiques, mais n'est pas modifié par des lésions faites au niveau du cortex cérébral, de l'amygdala, de l'habénula, du corpus callosum, et du bulbe olfactif.

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Research Associate. Consejo Nacional de Investigaciones Científicas.     

The effect of chlorpromazine on the adrenal gland in rats with brain stem lesions

Resumen Lesiones de la formación reticulada mesencefálica (FRM) provocan una caída significativa del ácido ascórbico supprarrenal (AAS). La clorpromazine (CPZ) provoca un aumento significativo del AAS. La administración de CPZ a ratas con lesión en FRM es incapaz de restablecer los niveles de AAS.     

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.     

Antagonism by thyrotropin-releasing hormone (TRH) of pentobarbital-induced hypothermia in rats with brain lesions

Summary Anesthesia with a large dose of pentobarbital (55 mg/kg, i.p.) caused a sustained decrease in brain temperature (Tb), which was monitored with a probe placed in the midbrain reticular formation. The administration of TRH to the lateral ventricle antagonized this hypothermia. None of the acute surgeries examined in this paper (adrenal-demedullectomy, septal knife cuts, electrolytic lesions of the hypothalamus and midbrain knife cuts) had any essential effect on this antagonism by TRH. These results suggest that centrally-administered TRH exerts its effect on thermoregulation, at least in part, through brain structure(s) caudal to the midbrain.     

Development of hyperphagia in female rats with ventromedial hypothalamic lesions placed at four different ages

Zusammenfassung Ventromedial-hypothalamische Läsionen führen bei nicht mehr säugenden weiblichen Ratten zu temporärer Hypophagie, bei älteren Tieren zu Hyperphagie. In den folgenden Wochen wird eine autonome Stabilität und normale Futteraufnahme wieder erreicht. Bezogen auf das Körpergewicht assen die nicht mehr säugenden Ratten weniger als gleich alte Kontrolltiere, mehr jedoch als ältere lädierte Ratten.

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This investigation was supported by U.S.P.H.S. Grant HE No. 06975 of the National Heart Institute.

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The author is grateful to Dr.Floyd R.Skelton for his criticism, help and support in this investigation.     

Antagonism by thyrotropin-releasing hormone (TRH) of pentobarbital-induced hypothermia in rats with brain lesions

Anesthesia with a large dose of pentobarbital (55 mg/kg, i.p.) caused a sustained decrease in brain temperature (Tb), which was monitored with a probe placed in the midbrain reticular formation. The administration of TRH to the lateral ventricle antagonized this hypothermia. None of the acute surgeries examined in this paper (adrenal-demedullectomy, septal knife cuts, electrolytic lesions of the hypothalamus and midbrain knife cuts) had any essential effect on this antagonism by TRH. These results suggest that centrally-administered TRH exerts its effect on thermoregulation, at least in part, through brain structure(s) caudal to the midbrain.     

Thrombosis of sympathectomized rats after strong excitation provoked by sound stimuli

Summary The data obtained are evidence of the decreased resistance of sympathectomized animals to excitement caused by afferent stimuli.     

Influence of treatment duration on audiogenic seizure susceptibility during barbiturate withdrawal in rats

Summary Barbiturate withdrawal seizure susceptibility in rats increased with increasing duration of treatment during a 15-day treatment period in which the animals were given an i.p. dose of sodium barbital every 12 h. This method of producing dependence has clear advantages over previously described methods.     

Influence of treatment duration on audiogenic seizure susceptibility during barbiturate withdrawal in rats

Barbiturate withdrawal seizure susceptibility in rats increased with increasing duration of treatment during a 15-day treatment period in which the animals were given an i.p. dose of sodium barbital every 12 h. This method of producing dependence has clear advantages over previously described methods.