摘要:

Abstract——(1) Gramicidin at low concentrations induces an uptake of K+and Na+in brain mitochondria in a manner similar to that observed with liver mitochondria.(2) The cation uptake is energy dependent, and is accompanied by an ejection of H+ions and a slight increase in respiration in the absence of added permeant anion.(3) The cation uptake and hydrogen ion release are both inhibited by agents which inhibit electron transport. Barbiturates and chlorpromazine inhibit the transport phenomenon by inhibiting electron transport.(4) In the presence of permeant anions (phosphate and acetate) respiration is stimulated quite significantly.(5) At high gramicidin concentrations there is a release of Na+and K+from the mitochondria and uptake of H+. There is also a cyclic reduction‐oxidation of the nicotinamide adenine dinucleotides, which is believed to be due to the release from the mitochondria of the reduced dinucleotides followed by their subsequent oxidation.(6) The effect of high gramicidin on the mitochondrial nicotinamide‐adenine dinucleotides and cation distribution is irreversible and is not blocked by individual inhibitors of respiration and of phosphorylation, but is prevented by prior addition of a mixture of these inhibitors.(7) Gramicidin is therefore believed to have a bimodal function; one on the mitochondrial membraneper se, and the other on the energy dependent ion accumulation apparatus.(8) A model of induced mitochondrial ion accumulation is pr

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11631.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——The concentrations of glycolytic intermediates were measured in aerobically incubated guinea pig cerebral cortex slices. Increasing the concentration of potassium in the medium increased fructose diphosphate ten‐fold and triose phosphates three‐fold. Omitting calcium increased all the glycolytic intermediates except pyruvate; triose phosphates were increased most. The changed patterns of the glycolytic intermediate profile in the slices are consistent with the previously proposed hypothesis that the phosphofructokinase is a main regulatory step in glycolysis. Glycolysis is also limited at the step of pyruvate kinase, which is inhibited in cerebral cortex slices. Calcium in the tissue and cellular organization of the slices were shown to be responsible for this inhibition. It was concluded that the effects of potassium and calcium on aerobic glycolysis in cerebral cortex slices are direct—on the pyruvate kinase—and also indirect. Calcium was shown to be inhibitive also to the activities of hexokinase, phosphoglucoisomerase, phosphofructokinase, glyceraldehyde 3‐phosphate dehydrogenase and enolase of guinea pig ce

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11632.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——Glutamic acid, glutamine, GABA and aspartic acid exhibited postnatal increases in the developing mouse brain at the same time that the other amino acids, both essential and non‐essential, of the pool decreased. The most significant decreases were observed in the concentrations of taurine, phosphoethanolamine, glycine and alanine. The period of rapid accumulation of the members of the glutamic acid family in the mouse brain was concurrent with dramatic increases and decreases in brain weight and water content, respect

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11633.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——A study has been made of the contribution of noradrenaline transport along sympathetic nerves to their terminal stores of transmitter by ligating the splenic nerves of the cat, and measuring both the noradrenaline that accumulates above the constriction, and the noradrenaline content of the spleen. The biochemical estimations were supplemented by fluorescence histochemistry. The effect of abolishing efferent impulses in the splenic nerves was examined by cutting their preganglionic nerve supply.The proximo‐distal flow rate for noradrenaline was calculated as 1.4‐3.3 mm/hr assuming that all the noradrenaline that accumulates is derived from the cell bodies in the ganglion without net addition or loss in the axons. The process was not dependent on impulse traffic in the nerves, since decentralization did not significantly effect the accumulation. The amount of noradrenaline arrested by the constriction in 24 hr was only 1 per cent of the stores in the terminals of those nerves, and consequently no change was detected in the spleen's noradrenaline content as a result of constricting its nerve supply.In the presence of an intact reflex pathway to the spleen, the stress of the operative procedure produced a marked constriction of the spleen, and depletion of its noradrenaline content. These changes could be prevented either by section of the preganglionic splanchnic nerves, or by ligation of the splenic nerves, thereby blocking the conduction of efferent nerve impulses.The evidence favours a proximo‐distal flow of noradrenaline in sympathetic nerves, independent of nerve impulses, which makes, however, a negligible quantitative contribution to the terminal stores of tr

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11634.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——Both [14C]noradrenaline and [14C]leucine were injected into the coeliac ganglia of cats in an attempt to label the noradrenaline and protein of the granular vesicles, so that their movement in the splenic nerves could be followed.When a constriction was placed on the nerves, labelled noradrenaline and protein accumulated just proximal to it, but there was no such accumulation below it, nor above a second, more distal constriction placed on the same nerve. This indicated that a neural transport mechanism, rather than uptake from the circulation, was responsible for the accumulation.Peaks of labelled noradrenaline and protein were observed to move down the axon at about 5 mm/hr. In addition a slow moving component of axonal protein, advancing at about 1 mm/day, was detected.The results demonstrate a rapid proximo‐distal movement of noradrenaline and protein which could represent the transport of granular synaptic vesicles from their site of manufacture in the cell body to their site of storage in the nerve terminals within the s

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11635.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——(1) Major organs of rats fed a 40 per cent galactose diet for one month were surveyed for changes in free myo‐inositol. The levels were reduced only in lens and sciatic nerve.(2) In nerve and lens the low myo‐inositol level was associated with high concentrations of galactitol and increased water content.(3) In nerve and lens myo‐inositol levels returned towards normal during a period of 1–2 weeks in which animals were fed a regular diet again. The pattern of change showed (a) an initial lag period, and (b) return to normal after galactitol concentrations had fallen to a low level and at the same time that water content returned to normal.(4) In nerve there were changes in scyllo‐inositol levels that paralleled those in myoinositol.(5) The evidence suggests that the inositol changes were related to the osmotic effects of galactitol accumulation rather than to a direct inhibition of myo‐inositol synt

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11636.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——Normal values for the concentration of 5‐HT, 5‐HIAA and tryptophan are established in various regions of the dog brain. After administration of tryptophan by intravenous injection the rise and fall of 5‐HT and 5‐HIAA were estimated at 1, 2 and 4 hr. Best fit quadratic regression curves obtained by computer programme were fitted to the data. Similar tryptophan doses were given to dogs and the 5‐HIAA concentration estimated in the cisternal CSF. Quadratic regression curves fitted to these values show that the concentration of 5‐HIAA in CSF reflects the changes of 5‐HIAA in the brain and in particular in the brain stem. a‐Methyl dopa pretreatment blocked the rise of 5‐hydroxyindoles in brain and CSF and appeared to inhibit tryptophan hydroxylase as

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11637.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——A substance resembling catecholamine found in chick hearts during the early stages of embryologic development was identified as DOPA. Cell cultures and fluorescence microscopy indicated intracellular location of this substance in myocardial cells. The absence of nerve tissue in the cell cultures was demonstrated by electron microsc

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11638.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——In the head of the caudate nucleus, the relative specific activity of glutamine (glutamic acid specific activity = 1) was less than 1 with intravenous [14C]leucine as the tracer metabolite. This is in contrast to observations made in other brain areas (cortex, hippocampus, thalamus, pons, and medulla) where the relative specific activity of glutamine was greater than 1. This is also in contrast to findings when [l‐14C]acetate was utilized as the tracer; under these conditions, in all brain areas, including the head of the caudate nucleus, the relative specific activity of glutamine was greater than 1. It is inferred that the differences in metabolism of [14C]leucine and [14C]acetate in the head of the caudate from that in other brain areas reflect differences in compartmentation of the glutamate‐glutamine

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11639.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY

摘要:

Abstract——A soluble protein (S‐100) which is unique to the nervous system was measured in rabbit tibial nerve at 0, 3, 7, 14, 21, and 28 days of degeneration. Amounts of S‐100 in the degenerated peripheral segment of the transected nerve fell progressively during degeneration to 2 per cent of that measured in the corresponding portion of nerve taken from control rabbits 28 days postoperatively. Total soluble proteins increased 42 per cent during this time. Levels of S‐100 and total soluble proteins remained unchanged in non‐degenerated nerve segments from experimental and control rabbits. Correlations of amounts of S‐100 measured in the study reported here with cellular changes demonstrated by other investigators to characterize Wallerian degeneration in peripheral nerve suggest that the S‐100 protein is localized primarily in axons rather than in Schwann

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1968.tb11640.x

出版商:Blackwell Publishing Ltd    

年代:1968

数据来源: WILEY