摘要:

AbstractWe have developed a radioligand binding assay based on the use of hypothalamic slices and have examined the ontogenesis of [3H]naloxone binding sites in male and female rats. [3H]NAL binding is reversible, saturable, stereospecific, of high affinity, readily displaceable by morphine and is sensitive to phenoxybenzamine. These characteristics suggest that [3H]NAL readily binds to opiate receptors in brain slices. With this assay we have demonstrated that: (a) there is an age‐related increase in opiate binding sites in rat hypothalamus, (b) there are sex differences in the binding affinity of the sites and (c) the values ofBmaxare approximately 2–5‐fold higher than the levels previously reported from assays with brain homogenates.

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90210-1

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractTrigeminal ganglia have been removed from five, six, seven and eight day chick embryos and explants of the dorso‐medial (DM) and ventro‐lateral (VL) parts of the maxillomandibular lobe were grown in tissue culture. Quantitative methods were used to assess the influence of nerve growth factor (NGF) on fiber outgrowth from these explants. At all ages outgrowth from DM explants was significantly greater than from VL explants, the difference being most pronounced between the extreme DM and VL poles of the maxillomandibular lobe. These observations are interpreted as indicating the existence of two distinct populations of neurons in terms of their response to NGF rather than the consequence of the asynchronous differentiation and maturation of the VL and DM neurons. A similar study of 10, 11 and 12 day embryonic mouse trigeminal ganglia revealed no significant difference in neurite outgrowth between DM and VL regions grown in the presence or absence of NGF.

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90211-3

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractPutrescine and spermidine acetylation is at least 10‐fold higher in the brain homogenate of the neonate (1‐day‐old) mouse than in the adult (90 days old). Although the pattern of putrescine and spermidine acetylation is similar throughout development, the acetylation of spermidine is consistently higher. As the animal matures, the activity curves tend to converge.In the P1(crude nuclei) and microsomal fractions, the acetylation of spermidine is highest at day 1, while putrescine acetylation peaks at day 4. In contrast to the adult animal, putrescine and spermidine acetylation are present in the P2(crude mitochondria) and soluble fractions. In the P2fraction, spermidine acetylation is highest at birth, while the acetylation of putrescine peaks at day 3. Acetylation of both substrates is barely detectable by day 42. In the soluble fraction, putrescine and spermidine acetylation show the highest activity at day 5. The activity declined towards adult values by day 10 in all the fractions examined.Acetylation of putrescine and spermidine is approximately 4‐fold higher in the brain homogenate of the 120‐day‐old mouse than in that of the 90‐day‐old mouse. Both the acetylation of putrescine and spermidine decline as the animal grows older. In contrast to the perinatal period (day 20 of gestation to 4 days old) the acetylation of putrescine is almost identical to that of spermidine in the adult mouse.These results suggest that polyamine acetylation may play an important role in polyamine metabolism in the developing mouse brain. The presence of activity in the P2and soluble fractions of the neonatal, but not adult mouse brain, suggests that putrescine, via acetylputrescine, may contribute to the GABA levels during development.

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90212-5

出版商:Wiley    

年代:2003

数据来源: WILEY

摘要:

AbstractIn the male rat, a dramatic increase in serum testosterone occurs during the first 2 h of postnatal life. Since the hypothalamus is known to be an important site for sexual differentiation of the brain, this early testosterone surge was a good model to use to study the transfer of serum testosterone to the hypothalamus and cerebral cortex. Endogenous testosterone was measured by radioimmunoassay in the hypothalamus and the cerebral cortex of the foetus and newborn rats during the first 6 h following birth. In the male, hypothalamic testosterone increased between 0 hin uteroand 2 h; in the males gonadectomized at 0 hin uteroand killed at the age of 2 h, the testosterone surge was abolished, clearly indicating the testicular origin of this hormone in the neonate. The small testosterone increase in the cerebral cortex compared with that in the hypothalamus reflects a preferential uptake of this hormone by the hypothalamus of the newborn. In the female, hypothalamic testosterone slightly decreased between 0 hin uteroand 6 h. These results are in agreement with the view that hypothalamic modifications form the basis for some behavioral and physiological changes attributed to the effect of perinatal hormonal stimulation.

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90213-7

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90215-0

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90218-6

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90221-6

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90224-1

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90226-5

出版商:Wiley    

年代:2003

数据来源: WILEY

ISSN:0736-5748    

DOI:10.1016/0736-5748(83)90230-7

出版商:Wiley    

年代:2003

数据来源: WILEY