摘要:

AbstractThe inhibitor of catecholamine synthesis at the tyrosine hydroxylase level, alpha‐methyltyrosine, administered in daily doses of 250 mg/kg IP, altered motor activity and aggressive behavior of isolated male mice in ten‐minute paired encounter tests conducted on nine successive days. Motor activity was determined by an electromagnetic activity meter which measures fine and coarse movements separately. Coarse motor activity correlated significantly with aggressive behavior. Nonagressive fine motor activity was significantly increased, while all the parameters of aggressive behavior showed a significant decrease in aggression. Increased escape behavior, heterogrooming, squeaking, and two cases of stupor were observed, suggesting possible equivalents of anxiousness. The defecation rate did not differ from that of the control group, victors having had a higher rate than losers.Results are discussed in connection with the “construct of emotionality” and the hypothesis of there being several categories of aggression with corresponding biochemical corre

ISSN:0360-4012    

DOI:10.1002/jnr.490040402

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

年代:1979

数据来源: WILEY

摘要:

AbstractIncorporation of U‐14C‐glucose into macromolecules (lipid, protein and nucleic acid fractions) of rat brain cortex slices was studied in vitro under conditions of anoxia and reoxygenation. Additionally, the influence of depolarization on control and postanoxic U‐14C‐glucose metabolism was investigated.Potassium‐induced depolarization of the slices lowered their capacity to incorporate14C from U‐14C glucose into proteins and nucleic acids without any changes in the labeling the lipids. Fifteen and 30 minutes of anoxia depressed the rate of14C incorporation into each of the above macromolecules. When slices after 15 minutes of anoxia were transferred to an oxygenated medium their capacity to incorporate14C from glucose into macromolecules was partly restored compared to the control.Excess of potassium in the medium during the reoxygenation period inhibited restoration of the synthetic capacity of the slices except lipids, into which incorporation of14C was even stimulated under depolarizing conditions.The influence of anoxia and depolarization were investigated also in different classes of lipids and proteins.14C incorporation into SDS‐extractable and residual proteins and phospholipid fraction containing phosphoinositol was closest to the control during reoxygenation which suggests the relatively highest resistance of these fracti

ISSN:0360-4012    

DOI:10.1002/jnr.490040403

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe influence of acute and prolonged (with resuscitation) hypoxia, upon some glycolytic substrates and high energy phosphate compounds in the rat brain, was studied. Acute hypoxia decreased the content of glucose and glucose‐6‐phosphate as well as of high energy phosphate compounds. Simultaneously, an increase of lactic acid level was recorded.Some adaptation features could be observed, when 30‐minute hypoxia with resuscitation was studied. Brain content of high energy compounds returned to the normal value, while that of glucose increased twice over control. However, the level of lactic acid was still incr

ISSN:0360-4012    

DOI:10.1002/jnr.490040404

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

年代:1979

数据来源: WILEY

摘要:

AbstractThe initial velocity of uptake of GABA by cortical synaptosomes from the Long‐Evans rat has been measured as a function of both sodium and GABA concentration. These data were then fitted to the rate equation for each of several possible models, and the models giving least error were identified. Although one cannot unequivocally distinguish between two of the models on the basis of the goodness of fit, deductions based on the fits of subsets of the models point to one of the two models. The major predictions from this model are as follows: (1) Uptake of GABA is totally sodium‐dependent. (2) Although plots of 1/v versus 1/[Na]2are nonlinear, the coupling ratio for transport (Na/GABA) is 2. (3) For transport to take place, the order of combination with carrier must be Na, Na, GABA. (4) Maximal velocity will occur only at infinite Na and GABA concentrations. (5) There is a sigmoidal relationship between apparent maximal velocity (Va) and [Na]. (6) Kt, the [GABA]that gives a velocity equal to Va/2, rises and then falls as [Na] is increased from zero, passing through a maximum at 33.52 mM [Na]. (7) The relationship between initial velocity and [Na] is sigmoidal. (8) Jm, rate of uptake with infinite [Na], is hyperbolically related to [GABA]; Jm approaches Vmax as [GABA]becomes very large. (9)KNa, the [Na] giving a velocity equal to Jm/2, declines rapidly from 10−7M to 10−5M GABA, but is essentially constant at 10−4M and above. (10) One GABA molecule is translocated per carrier molecule.The model is consistent with observations in the literature concerning the effects of sodium on the kinetics of

ISSN:0360-4012    

DOI:10.1002/jnr.490040405

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

年代:1979

数据来源: WILEY

摘要:

AbstractUptake of various amino acids was studied in slices from brain regions of rats four weeks after portocaval anastomosis.No differences of the inulin compartment were observed between control and experimental animals.After 60‐minutes incubation, uptake showed an overall pattern of diminution. This was more evident for some amino acids: valine, methionine, and lysine exhibited a lowering of about 30%, which was fairly uniform in the four tested regions; others showed a regional decrease – alanine in pons‐medulla, phenylalanine in cerebellum, histidine and GABA in mesodiencephalon.This decrease did not seem to be related to transport classes. The restricted entry of amino acids into brain cells in portocaval encephalopathy is somewhat difficult to explain; a decreased rate of protein synthesis may be of some importance, but other factors, such as a “carrier” impairment, effects on release and on amino acid metabolism, may also be

ISSN:0360-4012    

DOI:10.1002/jnr.490040406

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

年代:1979

数据来源: WILEY

摘要:

AbstractAmino acid levels have been determined in plasma and in four cerebral regions of rats one month after portocaval shunt. Many plasma amino acids are significantly lowered (asparagine, glutamine, threonine, serine, alanine, valine, leucine, isoleucine, cystine, lysine), while others remain unchanged (taurine, glycine, proline, tryptophan, ornithine, histidine, arginine). Asparagine and glutamine levels are significantly higher than in normal rats, and a net increase of tyrosine (100%), phenylalanine (50%) and citrulline (50%) is evident. In the shunted rat brain the most prominent feature is a very large rise (up to fivefold) of tyrosine, phenylalanine, histidine, citrulline, tryptophan, and glutamine uniformly in the tested regions. Other neutral amino acids are slightly increased. Lysine and arginine are decreased in cerebellum and pons‐medulla; taurine, in forebrain and cerebellum.Cerebral permeability to L‐amino acids was studied in vivo. Neutral amino acid permeability is greatly increased, whereas basic amino acids show a net decrease in their rate of passage from blood to the brain. No changes are observed for GABA and glutamic acid. These data suggest an altered permeability of the cerebral capillary membranes, which seems to be selective for the different amino acid transport classes. Competitive inhibition experiments demonstrate that the increased brain permeability to neutral amino acids after portocaval shunt is due to an enhancement of the saturable transport. The sharp rise in the brain of some essential neutral amino acids (phenylalanine, tyrosine, tryptophan, histidine), largely exceeding their changes in plasma, and the slight cerebral increase of other neutral amino acids despite their lowered level and the rise of competing amino acids in the plasma, is consistent with our observation of enhanced transport for the neutral class.In hepatic encephalopathy, correction of the altered plasma amino acid levels has been reported to improve the clinical status. If this result is connected to the concomitant correction of the brain amino acid levels, carefully selected competitive inhibition among various plasma amino acids could be a useful therapeutic tool in this pathologic condition. However, the increased activity of the neutral amino acid transport system adds a new factor to the problem, since it probably implies that the competing amino acids will accumulate to unphysiological levels in the br

ISSN:0360-4012    

DOI:10.1002/jnr.490040407

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

年代:1979

数据来源: WILEY

ISSN:0360-4012    

DOI:10.1002/jnr.490040401

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

年代:1979

数据来源: WILEY