Evidence for a neuronal release of isotopically labelled γ-amino-n-butyric acid (GABA) from the rat dorsal medulla in vivo

Summary High potassium and electrical stimulation consistently increase efflux of labelled GABA from the in vivo superfused rat dorsal medulla in a calcium-dependent fashion. The depolarizing alkaloid, veratridine, also evokes a large increase in efflux of labelled GABA. These data strongly suggest release from a neurotransmitter pool in this region.Supported by grants from the Science Research Council to N.D. and C.G.D., FAPESP and CNPq (Brazil) to J.A.A. and CAPES and FAPESP (Brazil) to N.B.     

Activation with (±)N-n-propyl-nor-apomorphine (NPA) of the male rat copulatory behavior

Summary I.p. (±)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.     

D(-)Lactic acid—a physiological isomer in the rat

Summary D(-)Lactate is produced in significant amounts together with L(+)lactate in the stomach of normal experimental rats. It is absorbed into the blood and constitutes a physiological isomer in this animal species.     

Activation with (+/-)N-n-propyl-nor-apomorphine (NPA) of the male rat copulatory behavior

I.p. (+/-)N-n-propyl-nor-apomorphine HCl (NPA) influences copulatory behavior of vigorous adult male rats in the same ways as apomorphine, i.e., it reduces the latency to ejaculation as well as mount and intromission frequency. Furthermore, NPA administered to impotent male rats restores normal mating behavior in some of them.     

Short-distance homing in a small mammal: the role of exteroceptive cues and path integration

Summary When hoarding food under IR light, the golden hamster returns to its nest by path integration after an active outward journey, and it is capable of compensating the angular component of a passive outward journey independently of auditory, olfactory, tactile and geomagnetic cues. If, however, peripheral visual cues are available, they predominate over information which is gained during the active or passive outward journey. Further experiments show the limitations of homing by path integration, which is open to cumulative errors and therefore needs to be complemented by other categories of information.Acknowledgments. This research was supported by the Fonds national suisse de la recherche scientique, grants No. 3.349.0.74 and 3.753.0.80. We are very grateful to Dr J. Bovet, Dr W. Heiligenberg, Dr J. G. Mather and to an unknown referee for their critical comments and to Mr R. Schumacher for all his ingenious technical help.     

Intergeneric interactions between Eimeria separata (Apicomplexa) and Nippostrongylus brasiliensis (Nematoda) in the rat

Ova production in Nippostrongylus brasiliensis infected rats was significantly greater than in rats singly infected with the helminth when Eimeria separata infections were introduced 4, 6 and 11 days postinoculation with N. brasiliensis. Patent periods were unaltered during concurrent infections. These results suggest that the presence of E. separata affects helminth fecundity but does not increase N. brasiliensis longevity as has been shown with E. nieschulzi.     

Hepatic regeneration in the rat after subtotal (90%) hepatectomy treated with testosterone

A single dose (120 mg/kg IM) of testosterone administered 1 month before subtotal hepatectomy (90%) in Rats, reduced liver steatosis and allowed complete liver regeneration.     

Distribution of 4-iodine-antipyrine (I131) in the rat

Resumen La determinación de agua total y de agua tisular se efectuo por medio de la dilución de 4-yodo-antipirina (I¹³¹) en la rata. Los resultados obtenidos muestran que la distribución regional del indicador no es similar a la del agua, aunque el volumen de agua total encontrado se aproxima a los valores medios normales. Esta distribución del indicador en los tejidos no hace aconsejable la utilización de este indicador para la medición del volumen de agua total o regional.     

Hormonal regulation of a new female-specific serum protein (FP) of the laboratory rat

Summary This paper reports evidence for a hormonal regulation of a new rat serum protein (female specific protein, FP) which is only demonstrable in female rats. Male and female rats were treated with testosterone and estrogen. The FP was assayed with immunological methods. The following results were obtained: 1. In testosterone-treated females the serum level of FP is reduced significantly. 2. In estrogenized males the FP was distinctly demonstrable but not in the control males.     

On the synthesis of serine and homoserine samples asymmetrically labelled with tritium and deuterium in the hydroxymethylene group

Summary (1 R) [1-³H,²H₁] 3-Phenylpropanol, the key intermediate in the synthesis of (4 R) [4-³H,²H₁] D, L-homoserine and of the (4 S)-isomer, is obtained from (1 S) [1-²H₁] 3-phenylpropanol and (1 RS) [1-³H] ethanol upon incubation with yeast alcohol dehydrogenase and NAD⁺; under similar conditions 2-phenylethanol undergoes very small exchange with [1-²H₂] ethanol.     

Studies on the growth ofPrymnesium parvum carter (chrysomonadina) and on the formation of its toxin (prymnesin)

Résumé Prymnesium parvum Carter atteint sa taille maximale en 9–10 jours et produit une grande quantité de toxine, quand il est cultivé à la lumiére dans un milieu comprenant des sels, du glycérol et certains acides aminés (sérine ou -alanine).

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Part of a Ph.D. thesis, submitted to the Faculty of Science, The Hebrew University, Jerusalem.