ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07105.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07106.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:Kinetic studies on the action of monoamine oxidase (MAO) in the regulation of Na+,K+‐ATPase were performed using 3‐methoxy‐4‐hydroxybenzaldehyde (MHB), which is an analogue of 3‐methoxy‐4‐hydroxyphenylacetylaldehyde (product of MAO‐catalysed reaction with dopamine as substrate). It was observed that at 2.6 μMMHB, the activation of Na+,K+‐ATPase may be the result of the removal of the inhibitory Ca2+, thereby increasing theVmax. Double‐reciprocal plots of Piversus MHB showed that Ca2+counteracted the effect of the aldehyde not by changing theKm, but be decreasing theVmaxof the Na+,K+‐ATPase stimulation. The removal of 3′,5′‐cyclic AMP‐dependent protein kinase from the microsomes by sodium dodecyl sulphate treatment abolished the activation and/or inhibition of the Na+,K+‐ATPase by aldehyde; it can therefore be inferred that 3′,5′‐cyclic AMP‐dependent protein kinase is inv

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07107.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The pattern of ontogenetic development of tryptophan (TP), tryptamine (T), indole‐3‐acetic acid (IAA), 5‐hydroxytryptamine (5‐HT; serotonin), and 5‐hydroxyindole‐3‐acetic acid (5‐HIAA) in the brains of rats aged 1–45 days is presented. Analysis of the five components in each brain allows the calculation of the acid/amine and amine/amino acid ratios. These metabolic indexes are a useful tool to study and compare the metabolic origins and fates of both amines. The ontogenetic patterns of TP, T, and IAA are very similar, especially during the first week postpartum. The highest and lowest levels found for T were 2.2 ng/g and 0.1 ng/g at the 1st and 5th day, respectively. The temporal relationship between the T/TP and IAA/T ratios suggests the existence of mechanisms protecting T against monoamine oxidase (MAO) which develop in parallel to synaptogenesis. Significant correlations were found between TP and IAA during the whole period studied and between TP and T during the first week after birth. The 5‐HT peak found during the first postpartum week could be due to a non‐neuronal pool of 5‐HT protected against MAO and possibly contained in mast cells. Preliminary determinations on leptomeningeal membranes suggest the e

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07108.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The sidedness of CDP‐choline:1,2‐diradylglycerol choline phosphotransferase (EC 2.7.8.2) and of the choline base‐exchange activity has been studied in rat brain microsomal vesicles. Proteases (trypsin and pronase) and mercury‐dextran have been used as reagents for membrane surface components. All of them could inactivate both enzymes to a good extent, without affecting the morphology or the permeability to sucrose of the vesicles. It is therefore concluded that CDP‐choline:1,2‐diradylglycerol choline phosphotransferase and the choline base‐exchange activity are localized on the outer surface of rat brain micros

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07109.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The activities of several enzymes involved in the metabolism of aspartate and glutamate were measured in striatal (nucleus caudatus and putamen) homogenates 2–3, 6–7, and 35–40 days following frontoparietal and frontal cortical ablation. The activity of glutamine synthetase (GS) was substantially increased (46–48%) on the operated side 6–7 days following the lesion whereas smaller changes were observed at 2–3 and 35–40 days after lesion. In contrast, decreased levels of glutaminase and malate dehydrogenase (MDH) were observed by 6–7 days while no significant change was found at either 2–3 or 35–40 days after the lesion. The activities of glutamate dehydrogenase (GDH) and glutamate decarboxylase (GAD) were elevated after 35–40 days whereas no changes in the levels of either GDH or aspartate aminotransferase (ASAT) were found at 2–3 or 6–7 days after the fronto‐parietal decortication. When only the frontal cortex was removed quantitatively similar changes were observed in striatal GS and glutaminase activity. The content of glutamate and glutamine in the denervated striatum followed qualitatively the changes in glutaminase and GS. The results indicate that the degeneration of cortico‐striatal terminals causes a profound glial reaction in the striatum, and both glutaminase and MDH are present in relatively high concentrations in

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07110.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The membrane‐bound acetylcholinesterase (AChE) from the electric organ ofTorpedo marmoratawas solubilized by Triton X‐100 or by treatment with proteinase K and purified to apparent homogeneity by affinity chromatography. Although the two forms differed only slightly in their subunit molecular weight (66,000 and 65,000 daltons, respectively), considerable differences existed between native and digested detergent‐soluble AChE. The native enzyme sedimented at 6.5 S in the presence of Triton X‐100 and formed aggregates in the absence of detergent. The digested enzyme sedimented at 7.5 S in the absence and in the presence of detergent. In contrast to the detergent‐solubilized AChE, the proteolytically derived form neither bound detergent nor required amphiphilic molecules for the expression of catalytic activity. This led to the conclusion that limited digestion of detergent‐soluble AChE results in the removal of a small hydrophobic peptide whichin vivois responsible for anchoring the protein to the li

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07111.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:Female rats were pair‐fed control or ethanol liquid diets on a chronic basis prior to parturition. Six brain regions (hypothalamus, cerebellum, brain stem, cortex, corpus striatum, and hippocampus) were dissected from 19‐ and 35‐day‐old rat offspring for the determination of dopamine (DA), sertonin (5‐HT), 3,4‐dihydroxyphenylacetic acid (DOPAC), 5‐hydroxyindole‐acetic acid (5‐HIAA), and homovanillic acid (HVA). DA, 5‐HT, and the acid metabolites were separated simultaneously by reverse‐phase HPLC and were quantitated using electrochemical detection. Between 19 and 35 days of age in control rats we observed an increase in the concentration of 5‐HT and 5‐HIAA in the corpus striatum and hippocampus and a decrease in these compounds in the cerebellum. In addition, there was a development‐related decrease of 5‐HIAA in the hypothalamus and an increase in the brain stem. During the same age period the concentration of dopamine increased in the hypothalamus and corpus striatum. There was also a development‐related decrease in the concentration of DOPAC in the corpus striatum and an increase in the cortex as well as a decrease in HVA in the cerebellum and cortex. In comparison to age‐matched control animals the 19‐ and 35‐day‐old offspring of ethanol‐treated rats had a lower concentration of 5‐HT and/or 5‐HIAA in the cortex, cerebellum, and brainstem. In addition the 35‐day‐old offspring of ethanol‐treated rats exhibited a decrease in DA and HVA in the cortex. The results of the present study suggest thatin uteroethanol exposure affects both

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07112.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:Some aspects of the physiological regulation of the pineal α1‐adrenoceptor have been studied using the selective, high‐affinity ligand [125I] iodo‐2‐[β‐(4‐hydroxyphenyl)ethylaminomethyl]tetralone ([125I]HEAT). Pineal glands taken from rats housed in a diurnal lighting cycle showed no circadian rhythm in the number of specific [125I]HEAT binding sites, although a characteristic rhythm in pineal melatonin was seen. It was established that the pineal α1‐adrenoceptor is under neural control because interruption of neural stimulation of the pineal by bilateral superior cervical ganglionectomy (SCGX) or by exposing rats to constant light for 3 weeks doubled receptor density but did not change affinity for [125I]HEAT. Administration of various α1‐adrenoceptor agonists either acutely (i.p. injection) or chronically (s.c. infusion) did not alter the number of specific [125I]HEAT binding sites. Together these results indicate that the pineal α1‐adrenoceptor, like the pineal β‐adrenoceptor, is regulated by sympathetic nerve activity, probably through the physiological release of the neurotransmitter norepinephrine. However the absence of a circadian rhythm in α1‐adrenoceptor number and lack of down‐regulation by adrenergic agonists imply diff

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07113.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The relationship between structure,in vivoactivity, andin vitroactivity of some analogues of the γ‐aminobutyric acid (GABA) agonist piperidine‐4‐sulphonic acid (P4S) was studied. The syntheses of 1,2,3,6‐tetrahydropyridine‐4‐sulphonic acid (DH‐P4S) and (RS)‐pyrrolidin‐3‐yl‐methanesulphonamide (PMSA‐amide) are described. Like P4S, its unsaturated analogue DH‐P4S and the five‐ring isomer (RS)‐pyrrolidin‐3‐yl‐methanesulphonic acid (PMSA) were bicuculline methochloride (BMC)‐sensitive inhibitors of the firing of neurones in the cat spinal cord. Whereas isonipecotic acid was less potent than its unsaturated analogue isoguvacine as a GABA‐mimetic and as an inhibitor of GABA binding, the opposite relative potencies of P4S and DH‐P4S were observed, P4S being proportionally more potent than DH‐P4S. In contrast with P4S and DH‐P4S, PMSA, which is an analogue of the potent GABA uptake inhibitor and BMC‐sensitive GABA‐mimetic homo‐β‐proline, was a relatively weak inhibitor of GABA uptakein vitro.PMSA‐amide was more than two orders of magnitude weaker than PMSA as an inhibitor of GABA binding and did not significantly affect GABA uptakein vitro.The effects of 3‐aminopropanesulphonic acid (3‐APS), PMSA, P4S, and DH‐P4S on the binding of [3H]diazepamin vitroat 30°C, in the presence or absence of chloride ions, were studied and compared with those of the structurally related amino acids GABA, homo‐β‐proline, isonipecotic acid, and isoguvacine. Under these conditions the aminosulphonic acids were weaker than the respective amino acids in enhancing [3H]diazepam bin

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb07114.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY