摘要:

Abstract:The electrophoretic pattern of soluble proteins from seven rat brain regions (amygdala, cerebellum, corpus striatum, cortex, hypothalamus, medulla, and midbrain) was examined by sodium dodecyl sulphate‐polyacrylamide gel electrophoresis. Although the number of protein bands (36) was identical in all brain regions studied, there were differences in their relative densities, the greatest variation occurring in the low‐molecular‐weight region of the electrophoretogram. The bulk of the soluble proteins had molecular weights between 23,000 and 90,000 daltons. The medulla and amygdala showed the greatest range of protein band concentration. A large number of protein bands in the midbrain and corpus striatum showed a greater concentration of protein compared to the same bands in the other regions. A protein band that migrated with the same characteristic as albumin was found. It was consistently high in all regions, the midbrains showing a 1.5‐fold greater concentration compared to other regions. Linear regression analysis of wet weight of regional brain tissue against protein concentration yielded a regression coefficient (r2) of 0.77. Midbrain and corpus striatum showed a relatively higher protein concentration:weight ratio than other

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08766.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:In rats rendered hyperthyroid by chronic treatment with L‐triiodothyronine (T3) hormone there was a 21 and 27% decrease, respectively, in the number of binding sites for [3H]flunitrazepam ([3H]FNZ) and [3H]ethyl‐β‐carboline‐3‐carboxylate ([3H]β‐CCE) without changes in affinity for the two ligands. Two weeks after thyroidectomy there was a 44% increase in [3H]FNZ sites and a 17% increase in [3H]β‐CCE binding sites.In vitrowe found that T3produces a decrease inBmaxand an increase inKD, both changes being characteristic of a mixed type of inhibition. Thyroid status dramatically affected theKiof T3in displacing [3H]FNZ from sites on isolated membranes of the cerebral cortex: in hypothyroid rats theKivalue was 0.9 μM, whereas in hyperthyroid rats it was 83 μM, a 92‐fold difference. In control rats, theKiwas 11 μMThese findings are discussed in relation to a possible modulation of benzodiazepine receptor

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08767.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The concentrations of cyclic AMP, noradrenaline, glycogen, glucose, lactate, pyruvate, labile phosphate compounds, and free fatty acids were investigated in the rat neocortex and hippocampus during and following cerebral ischemia. An incomplete ischemia of 5 and 15 min duration was induced by bilateral carotid clamping combined with hypotension. The postischemic events were studied after 5, 15, and 60 min of recirculation. Five minutes of ischemia did not significantly alter the neocortical or hippocampal concentrations of cyclic AMP. After 15 min of ischemia the neocortical levels decreased significantly below control values. In the recirculation period following ischemia a significant elevation of the cyclic AMP concentrations was observed. Following 5 min of recirculation after 5 min of ischemia the levels increased from 2.53 ± 0.21 nmol ± g−1to 5.18 ± 0.09 nmol ± g−1in the neocortex and from 2.14 ± 0.16 nmol ± g−1to 3.52 ± 0.35 nmol ± g−1in the hippocampus. Five minutes of recirculation following 15 min of ischemia led to a significant increase in the levels of cyclic AMP, to 12.86 ± 1.43 nmol ± g−1in the neocortex to 5.58 ± 0.57 nmol ± g−1in the hippocampus. With longer recirculation periods the cyclic AMP levels progressively decreased and were similar to control values after 60 min. Depletion of cortical noradrenaline by at least 95% was performed by injections of 6‐hydroxydopamine into the ascending axon bundles from the locus ceruleus. The lesion did not significantly change the ischemic or postischemic neocortical and hippocampal levels of cyclic AMP, glycogen, or free fatty acids including arachidonic acid. Treatment of the animals with theophyllamine (23, 46, and 92 mg ± kg−1) or indomethacin (10 mg ± kg−1) did not affect the postischemic levels of cyclic AMP. It is concluded that central noradrenergic neurons, prostaglandins, and adenosine are not of major importance for the observed postischemic elevations of cyclic AMP and that the changes in the concentrations of free fatty acids measured during and following ischemia are not me

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08768.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:Human serum cleaves two dipeptides from the N‐terminus of the neurohormone substance P. It has been suggested that this degrading activity is inherent to serum cholinesterase. We oppose this, because it turned out that highly purified serum cholinesterase contains traces of dipeptidyl peptidase IV, an enzyme known to attack the N‐terminus of substance P. The peptidase is incompletely separated from cholinesterase during the procainamidegel affinity chromatography as the last step of the usual purification procedure. Physostigmine completely inhibits the hydrolysis of butyrylthiocholine by such purified cholinesterase preparations, but not their substance P‐degrading activity. Vice versa, δ‐carbobenzoxy‐lysylproline, an inhibitor of dipeptidyl peptidase IV, inhibits the peptidase activity of these preparations more than their esterase activity. After rechromatography on procainamide gel the peptidase is completely separated and the remaining cholinesterase has lost its substance P‐degrading activity. We conclude that the N‐terminal region of substance P is not degraded by cholinesterase but by the contaminating dipeptidyl peptidase IV, a different

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08769.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The effect of undernutrition from the 16th day of pregnancy up to 70th day of life on blood glucose and ketone bodies and on several brain mitochondrial enzymes related to energy metabolism or biosynthetic function was investigated. Undernutrition in perinatal period was established by means of a food restriction to pregnant rats and, later, to the lactating mother; undernourished postweaned rats received half the diet consumed by the controls. Body and brain weight from undernourished rats was less than controls throughout the entire period studied. Glycemia and ketonemia were also always lower than controls. Cytochromecoxidase, citrate synthase, 3‐hydroxybutyrate dehydrogenase, 3‐oxoacid coenzyme A transferase, and acetoacetyl‐coenzyme A thiolase activities during the suckling period were in most stages lower than controls; subsequently, activities in undernourished rats reached or surpassed the control values. These results could explain the “catch up”phenomenon in several ultrastructural parameters found by other authors in undernourished postwe

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08770.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:γ‐Aminobutyric acid (GABA) was applied to the superior cervical ganglion (SCG) of CFY ratsin vitroandin vivo, with or without implantation of a hypoglossal nerve, to evaluate the effects of these experimental interventions on the acetylcholine (ACh) system, which mainly serves the synaptic transmission of the preganglionic input. Long‐lasting GABA microinfusion into the SCGin vivoapparently resulted in a “functional denervation.”This treatment reduced the acetylcholinesterase (AChE; EC 3.1.1.7) activity by 30% (p<0.01) and transiently increased the number of nicotinic acetylcholine receptors, but had no significant effect on the choline acetyltransferase (acetyl‐coenzyme A:choline‐O‐acetyl‐transferase; EC 2.3.1.6) activity, the ACh level, or the number of muscarinic acetylcholine receptors. The relative amounts of the different molecular forms of AChE did not change under these conditions.In vivoGABA application to the SCG with a hypoglossal nerve implanted in the presence of intact preganglionic afferent synapses exerted a significant modulatory effect on the AChE activity and its molecular forms. The “hyperin‐nervation”of the ganglia led to increases in the AChE activity (to 142.5%, p<0.01) and the 16S molecular form (to 200%, p<0.01). It is concluded thatin vivoGABA microinfusion and GABA treatment in the presence of additional cholinergic synapses has a modulatory effect on the elements of the ACh system

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08771.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:Deamination ofn‐octylamine andn‐decylamine has been studied in various tissues using a new bioluminescence technique. Selectivity ofn‐octylamine andn‐decylamine as substrates for monoamine oxidase (MAO) A or B has been determined using both clorgyline and (–)‐deprenyl inhibition curves and kinetic parameters. Homogenates of rat brain, liver and heart containing predominantly MAO‐A or ‐B were prepared by preincubation for 60 min with (–)‐deprenyl or clorgyline (30 nM), respectively. Human placenta (MAO‐A) and platelet (MAO‐B) were used as reference tissues containing only one MAO form. In tissues (rat liver, brain) containing both MAO forms in equal proportion, inhibition curve studies showed a preference of both substrates for the B form of the enzyme; however, where MAO‐A was the major form (rat heart, human placenta), clorgyline was the more effective inhibitor. In the beef brain cortexn‐octylamine showed marked preference for MAO‐B, whereasn‐decylamine was selective toward MAO‐A. Kinetic studies in general supported the picture of greater selectivity of the aliphatic amine substrates for deamination by MAO‐B, as reflected by lowerKmvalues for this enzyme type. However,n‐octylamine was more selective for MAO‐B thann‐decylamine in both kinetic and inhibition curve studies. The deamination of these aliphatic amine substrates cannot be explained only by reference to the binary

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08772.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:Thein vivoluminescence of an aldehyde‐requiring mutant of the luminous bacteriaVibrio harveyi(M42) increases dramatically upon the addition of longchain aliphatic aldehydes (C8–C16). The intensity of this luminescence is linearly related to aldehyde concentration. This property was utilized for the determination of monoamine oxidase activity usingn‐octylamine andn‐decylamine as substrates, which are converted by monoamine oxidase ton‐octylaldehyde andn‐decylaldehyde, respectively. The addition of the amine to a suspension containing rat liver mitochondria and M42 cells initiated a luminescence that was directly proportional to monoamine oxidase activity according to two parameters: (1) the rate of the initial increase in luminescence and (2) the final “steady‐state”level of luminescence. The new assay has advantages of high sensitivity, rapidity, the possibility to perform discontinuous as well as continuous monitoring of monoamine oxidase activity, and applicability to tu

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08773.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:The activity of transglutaminase (TG) was examined in the rat superior cervical ganglion (SCG) during development and after postganglionic nerve crush. During postnatal development the enzyme activity is increased by sevenfold in parallel to protein content of the ganglion and reaches adult levels by day 35 after birth. The endogenous activity (enzyme activity assayed in the absence of the exogenous substrate) during development is transiently elevated with a peak at day 21 postnatal. In the adult ganglion the enzyme specific activity is evenly distributed in all subcellular compartments, but most of it is contained in the cytosol. Within the first hour after axotomy TG activity is rapidly and transiently elevated. The peak value, 80% above control levels, is attained by 30 min postoperative. At this time the activity is increased in all subcellular fractions, but the endogenous activity is selectively increased in the fraction containing nuclei. The enhanced TG activity after axotomy can be prevented by topical treatments with verapamil, an inhibitor of voltage‐dependent calcium fluxes across excitable membranes, or with the calcium chelator EGTA. The results show that intracellular TG activity is present in the SCG and that it increases with postnatal growth of the ganglion. After axotomy the enzyme activity is rapidly and transiently increased in the ganglion and this elevation critically depends on calcium fluxe

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08774.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY

摘要:

Abstract:Changes in plasma membrane potential of isolated bovine adrenal chromaffin cells were measured independently by two chemical probe methods and related to corresponding effects on catecholamine secretion. The lipophilic cation tetraphenylphosphonium (TPP+) and the carbocyanine dye 3,3′‐dipropylthiadicarbocyanine [DiS‐C3‐(5)] were used. The necessity of evaluating the subcellular distribution of TPP+among cytoplasmic, mitochondrial, secretory granule, and bound compartments was demonstrated and the resting plasma membrane potential determined to be – 55 mV. The relationship between membrane potential and catecholamine secretion was determined in response to variations in extracellular K+and to the presence of several secretagogues including cholinergic receptor ligands, veratridine, and ionophores for Na+and K+. The dependence of potential on K+concentration fit the Goldman constant field equation with a Na/K permeability ratio of 0.1. The dependence of both K+‐ and veratridine‐evoked catecholamine secretion on membrane potential exhibited a potential threshold of about – 40 mV before a significant rise in secretion occurred. This is likely related to the threshold for opening of voltage‐sensitive Ca2+channels. Acetylcholine and nicotine evoked a large secretory response without a sufficiently sustained depolarization to be detectable by the relatively slow potential sensitive chemical probes. Decamethonium induced a detectable depolarization of the chromaffin cells. Veratridine and gramicidin evoked both membrane depolarization and catecholamine release. By contrast the K ionophore valinomycin evoked significant levels of secretion without any depolarization. This is consistent with its utilization of an intracellular source of Ca2+and the independence of its measured secretory response on

ISSN:0022-3042    

DOI:10.1111/j.1471-4159.1985.tb08775.x

出版商:Blackwell Publishing Ltd    

年代:1985

数据来源: WILEY