The plasma volume of the Wistar rat in relation to the body weight

Summary The plasma volume of 43 male Wistar rats, weighing between 140 and 350 g, was determined. A close linear relationship between plasma volume and body weight was found: plasma volume (ml)=0.0291×body weight (g)+2.54.Acknowledgment. The excellent assistance of Mr J.S. Bouwer in animal experiments is gratefully acknowledged.     

Sectioning of polyacrylamide slab gels with a modified small animal stereotaxic instrument

Summary A simple and inexpensive modification of the Kopf model 900 small animal stereotaxic instrument allows it to be used temporarily as a precision polyacrylamide slab gel slicer.Supported by the Alfred P. Sloan Foundation.     

ACTH-induced hyperalgesia in rats

Summary The injection of ACTH 1–24 into the cerebral ventricles in rats markedly reduces the reaction time in the hotplate test and the nociception threshold in the tail-stimulation test. Morphine antagonizes and naloxone potentiates this hyperalgesic effect of ACTH. It is proposed that ACTH peptides play a physiological role in nociception.     

The stimulation of rat brain monoamine oxidase by dietary lithium chloride.

Lithium chloride administered to rats in drinking water for 30 days caused an increase of whole brain monoamine oxidase specific activity to approximately 140% of control. Carboxylesterase and formyltetrahydrofolate synthetase activities were not affected by Li+ either in vivo or in vitro.     

Increasing porosity of the incubating alligator eggshell caused by extrinsic microbial degradation

Summary The outer densely calcified layer of the alligator eggshell shows progressive crystal dissolution, with the production of concentrically stepped erosion craters, as incubation progresses. This dissolution is caused by the acidic metabolic byproducts of nest bacteria. Extrinsic degradation serves to gradually increase the porosity and decrease the strength of the eggshell.The work is supported by M.R.C. grant No. G979/386/CB and E.H.S.S.B. grant No. EB 109/74/75.     

On the excretion of 17-ketosteroids in guinea pigs

Zusammenfassung Im Harn von weiblichen Meerschweinchen wurde im Gegensatz zu männlichen Tieren Epiandrosteron als Haupt-17-Ketosteroid nachgewiesen.Untersuchungen über die 17-Ketosteroidkonjugate im Harn von weiblichen Meerschweinchen ergaben, dass ein grosser Teil (30–40%) als freie Steroide nachweisbar ist. 40–50% liegen als Schwefelsäurekonjugate und 3–6% wahrscheinlich als Glucuronide vor. Bei den konjugierten 17-Ketosteroiden handelt es sich vornehmlich um 11-oxygenierte Steroide.     

Eine neue morphologische Deutung des Vogelgehirns auf Grund neuer Forschungsergebnisse

Summary The embryological fact (Kallén) that hyperstriatum, neostriatum and archistriatum in birds are homologous to the neopallium, palaeostriatum primitivum and augmentatum to the basal ganglions of the mammals, is made probable by recent results in the fields of morphology, physiology and animal psychology.The differentiation and form of the neopallial parts of the birds brain is not produced by a surface development, as in mammals, but in a three dimensional structure of the hemisphere, by mass in birds.This differentiation is strongly pronounced in highly cerebralized forms, and the stratified arrangement of the elements is to be interpreted as a structure of integration.With regard to function and organization, the neopallium of birds is strictly comparable to that of mammals.