Electrocorticographic activity induced by gamma hydroxybutyrate in the rat during ontogenesis

Summary GHB at a dose of 200 mg·kg^–1 i.p. elicited groups of slow waves with a frequency of 4–5 Hz in both frontal and occipital ECoG leads in adult rats. In 25- and 18-day-old rats similar slow wave activity became continuous and exhibited a clear-cut maximum in the frontal regions. In 15- and 12-day-old animals slow wave activity was also registered in the frontal region but it was organized into short groups of unstable frequency. No ECoG effects of GHB could be found in 9-day-old rats.     

42K spaces in submandibular gland of early postnatal rats: effects of carbachol and transport inhibitors

Equivalent spaces of 42K were measured in fragments of the submandibular gland of 1-, 7-, 14- and 21-day-old and adult rats in the absence and presence of carbachol and the transport inhibitors ouabain and furosemide. The results indicate that the 42K space was increased by carbachol in an ouabain-sensitive manner at all ages studied and that part of the secretagogue-stimulated K uptake occurred by way of a furosemide-sensitive transport system in the latter part of the postnatal period and in the adult.     

42K spaces in submandibular gland of early postnatal rats: effects of carbachol and transport inhibitors

Summary Equivalent spaces of⁴²K were measured in fragments of the submandibular gland of 1-, 7-, 14- and 21-day-old and adult rats in the absence and presence of carbachol and the transport inhibitors ouabain and furosemide. The results indicate that the⁴²K space was increased by carbachol in an ouabain-sensitive manner at all ages studied and that part of the secretagogue-stimulated K uptake occurred by way of a furosemide-sensitive transport system in the latter part of the postnatal period and in the adult.     

The effect of skim milk on plasma cholesterol in rats.

From the 15th day of birth, newborn rats were offered rat chow mixed with water or skim milk. The former also received tap water, the latter skim milk. In the latter group, plasma cholesterol was lowered in 43- and 64-day-old males and in 64-day-old females.     

Ovarian HCG-binding in hemicastrated immature female rats

Summary Hemigonadectomy in 9-day-old female rats results in a drastic increase in the weight and the number of HCG-binding sites of the remaining ovary during further development. However, on a per mg basis of ovarian weight, the number of HCG-receptors is identical in hemicastrated and control rats.     

Protracted analgesia in young and adult rats maternally exposed to methadone

Summary The analgesic response to the hot-plate test was studied in 21-, 45-, 60-, 120- and 300-day-old rats maternally exposed to methadone (5 mg/kg). An elevation in nociceptive threshold, in the absence of further exposure to methadone, was observed in young and adult rats perinatally subjected to methadone.This research was supported by grant DA 01618.     

Na, K ATPase activity during early postnatal development of the rat submandibular gland

The activity of the ouabain-sensitive Na, K ATPase was measured in membrane fractions of the submandibular gland of 1-, 7-, 14- and 21-day-old rats. This activity increased with age and reached adult levels by 21 days.     

Na,K ATPase activity during early postnatal development of the rat submandibular gland

Summary The activity of the ouabain-sensitive Na, K ATPase was measured in membrane fractions of the submandibular gland of 1-, 7-, 14- and 21-day-old rats. This activity increased with age and reached adult levels by 21 days.     

Differential alterations in branched-chain amino acid decarboxylation in liver of hypophysectomized rats.

Valine decarboxylation was significantly increased and leucine decarboxylation was significantly decreased in rat liver slices following hypophysectomy. In both normal and hypophysectomized rats decarboxylation of leucine exceeded that of valine in slices whereas the reverse was observed with the respective keto acids and mitochondria.     

Monolayer cultures of perikarya isolated from postnatal rat cerebellum.

Viable cerebellar perikarya of mixed cell type obtained from 7--9-day-old rats were maintained in monolayer cutlure for up to 12 days. During this time extensive neurite formation and outgrowth occurred. The large majority of the cells developing in culture were tentatively identified as granule neurons. This identification was based on the large number isolated from the starting tissue, and the cells' general morphological features in culture such as perikaryal and nuclear size, the bipolar nature of neurite extension, and their migratory behaviour.     

Deficits in synapse-to-neuron ratio due to early undernutrition show evidence of catch-up in later life

Summary 30-day-old rats undernourished from birth are known to have large deficits in the synapse-to-neuron ratio in certain brain regions. It has not been possible to demonstrate any statistically significant deficits in this ratio in animals undernourished from birth to 30 days but then provided with an ad libitum amount of food till 6 months of age.Acknowledgments. This work was supported by the Medical Research Council and the National Fund for Research into Crippling Diseases.     

Effects of enterally- and parenterally-administered bombesin on intestinal luminal tryptic activity and protein in the suckling rat

Because of the presence of bombesin-like immunoreactivity in milk, we investigated if enteral administration of bombesin affects the intestinal luminal content of trypsin and protein in 12-14-day-old rats. Bombesin (40 micrograms/kg), given either orogastrically or subcutaneously, produced a significant elevation in the intestinal content of trypsin activity. Thus, enterally-administered bombesin can produce acute biologic effects in suckling rats.     

Differential alterations in branched-chain amino acid decarboxylation in liver of hypophysectomized rats

Summary Valine decarboxylation was significantly increased and leucine decarboxylation was significantly decreased in rat liver slices following hypophysectomy. In both normal and hypophysectomized rats decarboxylation of leucine exceeded that of valine in slices whereas the reverse was observed with the respective keto acids and mitochondria.Acknowledgments. This study was supported by the National Institutes of Health and the Samuel A. Berger Foundation.     

Direct evidence for pH-dependent Fc receptors on proximal enterocytes of suckling rat gut.

By means of an erythrocyte-antibody rosette technique, Fc receptors, functional at pH 6.0 but not at 7.2, were shown to be present on enterocytes isolated from duodenum and jejunum (but absent from ileum) of 12-20-day-old suckling rats.     

Influence of light on the plasma gonadotropin concentrations in the newborn rat.

The physiological increase in plasma gonadotropin (LH and FSH) levels in newborn rats is indisputably influenced by light. Permanent illumination accentuates this increase, whereas darkness decreases it in 16-day-old female rats. In male rats of the same age, only permanent illumination was tested with the same results.     

Plasma 1,5-anhydroglucitol in experimental galactosemia in the rat

Feeding with a galactose-rich diet induced a substantial drop in blood plasma 1,5-anhydroglucitol concentration. The decline was proportional to the dose of galactose. The decline was less marked in xylose-fed rats.     

Plasma 1,5-anhydroglucitol in experimental galactosemia in the rat

Summary Feeding with a galactose-rich diet induced a substantial drop in blood plasma 1,5-anhydroglucitol concentration. The decline was proportional to the dose of galactose. The decline was less marked in xylose-fed rats.     

Accumulation of cholesteryl esters associated with cerebellar hypoplasia in jaundiced Gunn rats

A marked accumulation of cholesteryl esters in the cerebellum of 20-day-old jaundiced homozygous Gunn rats was shown by quantitative TLC analyses and it was larger than that found in heterozygotes.     

Variations au cours de la journée de l'incorporation in vivo de la leucine tritiée dans les protéines du cervelet et du cerveau du jeune rat normal et hypothyroïdien

Summary In the normal and hypothyroid 6-day-old rat, the specific radioactivity (RSA) and the relative RSA (ratio of the RSA to the [³H] leucine concentration of the acido soluble phase) of the cerebral and cerebellar proteins, change during the day synchronally. They show a maximum at 15.00 h and a minimum at 03.00 h. At all stages studied, these values are significantly lower in the hypothyroid animals than in normal ones.     

Effects of enterally- and parenterally-administered bombesin on intestinal luminal tryptic activity and protein in the suckling rat

Summary Because of the presence of bombesin-like immunoreactivity in milk we investigated if enteral administration of bombesin affects the intestinal luminal content of trypsin and protein in 12-14-day-old rats. Bombesin (40 g/kg), given either orogastrically or subcutaneously, produced a significant elevation in the intestinal content of trypsin activity. Thus, enterally-administered bombesin can produce acute biologic effects in suckling rats.