摘要:

AbstractBilateral secretion of epinephrine and/or norepinephrine from adrenal medullae occurred in 76% of cats studied following unilateral electrical stimulation of sites in the hypothalamus or rostral mesencephalon. Responses were generally greater on the ipsilateral side. In most experiments, epinephrine alone or both epinephrine and norepinephrine outputs were increased. In only two experiments norepinephrine output was increased. Stimulation of most hypothalamic sites that evoked bilateral secretion was accompanied by an increase in blood pressure. Stimulation of effective sites in the mesencephalon was not generally accompanied by blood pressure changes.

ISSN:0360-4012    

DOI:10.1002/jnr.490080102

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

Abstract3‐Hydroxyacyl‐CoA dehydrogenase (HAD) has been widely used to assess the capacity for fatty acid oxidation by different muscle fiber types, with various Krebs cycle enzymes as a base for comparison. We have measured this enzyme in individual lyophilized fibers of the guinea pig soleus and the white and red portions of the vastus lateralis, and compared its activity in each fiber with that of lipoamide dehydrogenase (LAD), which as a part of the pyruvate dehydrogenase complex fulfills a function similar to HAD in forming acetyl‐CoA, but from pyruvate and, thus, mainly from a carbohydrate source. The mean HAD/LAD ratio was 17.2 ± 3 in the red vastus, 24.9 ± 3 in the white vastus, and 43.7 ± 10 in the soleus, all differences being highly significant. The two types of fast fibers were not distinguished from one another by the enzyme ratio within either the white or the red portion of the vastus lateralis. Data from all of the fast fibers taken together indicate a close correlation (0.93) between the two enzymes, whereas values from the soleus indicate a specialization of the mitochondria of the slow muscle fibers for the oxidation of fat

ISSN:0360-4012    

DOI:10.1002/jnr.490080103

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractMonoamine oxidase type B (MAO‐B) was similarly active in the hypothalamus of 60‐day‐old male and female Charles River rats. A single, 2 mg/kg IP injection of deprenyl, however, resulted in a significantly greater inhibition of hypothalamic MAO‐B in normal males than in normal females. Repeated administration of estrogen (estradiol valerate) to intact males postnatally, a treatment which disrupts the masculinization process, although not provoking true “feminization,” decreased the inhibition of MAO‐B, thus abolishing the sex‐specific difference. The intensity of deprenyl‐provoked hypothermia and ptosis in males exceeded that of females; neonatal and postnatal estrogenization of males resulted in diminution of these effects. Androgen administration to neonate females did little affect the biochemical and in vivo parameters of MAO inhibition. It is concluded that sex‐specific, biochemical differences in MAO‐B inhibition may have pharmacological correlates, and both facets of MAO inhibition are sensitive to neonatal

ISSN:0360-4012    

DOI:10.1002/jnr.490080104

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractTyrosine hydroxylase (TH) was studied in the entire hypothalamus of 60‐day‐old male and female rats, and its activity was similar in both sexes. Administration of estrogen or androgen to male or female pups soon after birth and during development did not affect the kinetic parameters of TH. It is, thus, suggested that sexual dimorphism in the levels and turnover of catecholamines (CA) and their sensitivity to fluctuations in gonadal steroids during development do not depend on corresponding sex‐related or steroid‐sensitive differences in the synthesis of hypothal

ISSN:0360-4012    

DOI:10.1002/jnr.490080105

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractAcetylcholine receptor (AChR) activities were followed in regenerating muscle grafts of rats. The effects of prior nerve crush or treatment with Marcaine on α‐Bungarotoxin binding in graft muscle extracts were compared to nontreated controls. All treatment groups displayed a similar but characteristic pattern in which minor differences in the time course and absolute levels of AChR activities were observed. These results are interpreted in terms of possible alterations in AChR levels brought about by the changes in the degree of graft innervati

ISSN:0360-4012    

DOI:10.1002/jnr.490080106

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractTwo techniques are described that are designed to elicit long and constant postsynaptic depolarizations or agonist‐induced currents by the electrophoretic application of agonists to endplate membranes. In the first technique, which can be described as a “pharmacologic voltage clamp,” the current flowing through the agonist pipette is controlled by the potential across the endplate membrane. Sustained depolarizations of constant amplitude can be obtained in this manner, while the agonist current needed to produce and maintain the response is recorded. The second technique uses a signal proportional to the current flowing across a voltage‐clamped endplate membrane to control the delivery of agonist. This allows control of the intensity of the agonist‐induced current. The possible application of these techniques in studying receptor desensitization and obtaining samples of post‐synaptic current noise for spectral analysis i

ISSN:0360-4012    

DOI:10.1002/jnr.490080107

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractTay‐Sachs disease and normal fetal cerebellar cells were maintained in culture for up to four weeks. Elevated levels of the lysosomal enzymes hexosaminidase B, β‐galactosidase, and acid phosphatase were observed in the Tay‐Sachs cells in long term cultures although elevated lysosomal enzyme levels were not observed in the normal cultures. Similarly, elevated lysosomal enzyme activities were observed in Tay‐Sachs cultures which had been treated with Concan

ISSN:0360-4012    

DOI:10.1002/jnr.490080108

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe concentration of dopamine in striatal slices obtained from rats treated with an MAO inhibitor was increasd significantly by a 50‐minute incubatio in oxygenated Krebs buffer at 37°C. Administration of α‐methyl‐p‐tyrosine did not antagonize this small increase in dopamine. The extent of the incubatio‐induced increase was much greater in tissue obtained from control rats and was also greater than that resulting from the intraperitoneal administration of γ‐butyrolactone (GBL). Prior administration of α‐methyl‐p‐tyrosine, d‐amphetamine, apomorphine, or lergotrile significantly antagonized the increases in striatal dopamine levels induced by GBL administration or by incubation of striatal slices obtained from control rats. The prior administration of phenylethylamine, however, antagonized the incubation‐induced, but not the GBL‐induced, increase in striatal dopamine. In conclusion, the effect of incubating striatal slices on their dopamine levels was similar to that of administering GBL in that the incubation enhanced the activity of tyrosine hydroxylase that in turn produced an accele

ISSN:0360-4012    

DOI:10.1002/jnr.490080109

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractThe intracellular volume of neoplastic brain cells was investigated with regard to the effects of hypo‐osmolality and hyperosmolality utilizing double isotopic labeling with 3–0‐methyl‐D‐glucose or tritiated water to measure the total volume of the pellet and inulin or polyethyleneglycol to measure the extracellular volume of the pellet. The cellular pellets were rapidly separated from the incubation medium by centrifugation after addition of an oil mixture. After 60 minutes incubation in Hanks balanced salt medium, the intracellular volume was 7.50 ± 0.64, 8.48 ± 0.19, and 2.97 ± 0.18 ml H2O per 106packed cells for C‐6 glioma cells, N18TG‐2 neuroblastoma cells, and NG108‐15 neuroblastoma X glioma hybrid cells, respectively. The extracellular trapped space of these cultured cells was about one third of the intracellular volume. The intracellular volume of C‐6 glioma cells was increased in hypotonic environment, whereas it was decreased with hyperosmolality. Both intracellular sodium and potassium were increased with increased osmolality of the incubation media. These data indicate iso‐osmotic regulation by tumor cells, i.e., there is a good correlation between the intracellular volume, intracellular cations and lactate levels of C‐6 glioma cells under va

ISSN:0360-4012    

DOI:10.1002/jnr.490080110

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY

摘要:

AbstractOf the Na, K‐ATPase activity in brain homogenates from 20‐, 60‐, and 120‐day‐old rats, 1.4 to 2.6% was recovered in myelin. The relative specific activities, at 0.2 to 0.3 times the specific activities in the rat brain homogenates, did not decrease during development, and myelin from bovine brain white matter had a similar relative specific activity. Oligodendrocytes from rat brains and bovine white matter had approximately one third the Na, K‐ATPase specific activities found in myelin from the respective sources. The Mg‐ATPase activity in rat brain myelin decreased during development and, in myelin from adult rats, was much lower than the Na, K‐ATPase activity. Notably, oligodendrocytes from both the forebrains of 10‐ to 120‐day‐old rats and from bovine white matter had high Mg‐ATPase activities. Whereas Na, K‐ATPase may be intrinsic to certain regions of the myelin sheath, the Mg‐ATPase in isolated myelin probably arises from fragments o

ISSN:0360-4012    

DOI:10.1002/jnr.490080111

出版商:Wiley Subscription Services, Inc., A Wiley Company    

年代:1982

数据来源: WILEY