Effects of ʟ-Phenylalanine on Acetylcholinesterase, (Na+,K+)-ATPase and Mg2+-ATPase Activities in Adult Rat Whole Brain and Frontal Cortex

2001 ◽  
Vol 56 (1-2) ◽  
pp. 132-137 ◽  
Author(s):  
Stylianos Tsakiris
Keyword(s):  
Atpase Activity ◽  
Frontal Cortex ◽  
Ache Activity ◽  
Brain Homogenate ◽  
Inhibitory Effect ◽  
Whole Brain ◽  
Adult Rat ◽  
Brain Ache ◽  
Developmental Factors ◽  
Stimulation Of

Abstract The effect of different L-phenylalanine (Phe) concentrations (0.12-12.1 mм) on acetylcho­ linesterase (AChE), (Na+,K+)-ATPase and Mg2+-ATPase activities was investigated in homogenates of adult rat whole brain and frontal cortex at 37 °C. AChE, (Na+,K+)-ATPase and Mg2+-ATPase activities were determined after preincubation with Phe. AChE activity in both tissues showed a decrease up to 18% (p<0.01) with Phe. Whole brain Na+,K+-ATPase was stimulated by 30-35% (p<0.01) with high Phe concentrations, while frontal cortex Na+,K+-ATPase was stimulated by 50-55% (p<0.00l). Mg2+-ATPase activity was increased only in frontal cortex with high Phe concentrations. It is suggested that: a) The inhibitory effect of Phe on brain AChE is not influenced by developmental factors, while the stimulation of Phe on brain Na+,K+-ATPase is indeed affected; b) The stimulatory effect of Phe on rat whole brain Na+,K+-ATPase is decreased with age; c) Na+,K+-ATPase is selectively more stimulated by high Phe concentrations in frontal cortex than in whole brain homogenate; d) High (toxic) Phe concentrations can affect Mg2+-ATPase activity in frontal cortex, but not in whole brain, thus modulating the amount of intracellular Mg2+.

Abstract 341: Synergistic Effects of Renal Dopamine and Gastrin Receptors in Hypertension

Hypertension ◽  
2012 ◽  
Vol 60 (suppl_1) ◽  
Author(s):  
Yue Chen ◽  
Shuo Zhen ◽  
Laureano Asico ◽  
Pedro Jose ◽  
Chunyu Zeng
Keyword(s):  
Atpase Activity ◽  
Sodium Excretion ◽  
Synergistic Effects ◽  
Inhibitory Effect ◽  
Receptor Interaction ◽  
Gastrin Receptor ◽  
Wky Rats ◽  
Link Type ◽  
Renal Dopamine ◽  
Stimulation Of

Oral NaCl produces stronger natriuresis and diuresis as compared with venous infusion of same amount of NaCl, indicating the existence of renal-gastric axis. Although numerous hormones are secreted in gastrointestinal tract, gastrin is evident one due to its natriuretic effects and taken-up by the renal proximal tubule (RPT) cells. We hypothesize that there is an interaction between gastrin and dopamine receptor in kidney, which synergistically increases sodium excretion, the impaired interaction would be involved in the pathogenesis of hypertension. In WKY rats, infusion of gastrin, via renal artery, induced natriuresis and diuresis, which was blocked in the presence of CI988, a gastrin receptor blocker. Similarly, the natriuretic and diuretic effect of fenoldopam, a D1-like receptor agonist, was blocked by the D1-like receptor antagonist, SCH23390 , indicating that gastrin and fenoldopam, via individual receptor, play natriuretic and diuretic effects. Our further study found that lower dosages of gastrin or fenoldopam could not induce natriuresis and diuresis alone, while putting together induced natriuretic and diuretic effects. The above-mentioned effects were lost in SHRs. We also found, in the presence of SCH23390 , gastrin-mediated natriuresis and diuresis was partially blocked. Similarly, in the presence of CI988, the natriuretic and diuretic effects of fenoldopam were partially blocked, indicating the interaction between gastrin and D1-like receptor. The gastrin/D1-like receptor interaction was also confirmed in the RPT cells. Stimulation of one receptor increased the expression of the other. Stimulation of either D1-like receptor or gastrin receptor inhibited the Na + -K + -ATPase activity in RPT cells, while in the presence of SCH23390 , the inhibitory effect of gastrin on Na + -K + -ATPase activity was partially blocked. In the presence of CI988, D1-like receptor-mediated inhibitory effect of Na + -K + -ATPase activity in RPT cells was partially inhibited. It indicated the synergistic effect between gastrin and D1-like receptor would increase the sodium excretion in WKY rats; the impaired interaction might be involved in the pathogenesis of hypertension.

Effect of Some Flavonic Compounds and Ascorbic Acid on Lactoferrin Stimulation of Erythrocyte Glycolysis and Na+/K+-ATPase Activity

2008 ◽  
Vol 63 (9-10) ◽  
pp. 773-779 ◽  
Author(s):  
Ana Maneva ◽  
Borislava Taleva
Keyword(s):  
Ascorbic Acid ◽  
Atpase Activity ◽  
Specific Binding ◽  
Lactate Production ◽  
Inhibitory Effect ◽  
High Concentration ◽  
Transport Chain ◽  
Strong Inhibitory Effect ◽  
Lactate Formation ◽  
Stimulation Of

The aim of the present study was to assess if some flavonic compounds (quercetin, piceatannol and apigenin) and ascorbic acid could interfere with the Lf stimulatory effect on the erythrocyte function. Quercetin (1.5 μm) and piceatannol (30 μm) showed an additive effect on Lf stimulation of Na+/K+-ATPase when used together with Lf. The enhancement of Lf stimulation on Na+/K+-ATPase in the presence of flavonoids was probably due to their antioxidative properties and/or to their involvement in the erythrocyte signaling. None of the estimated flavonoids showed an effect on Lf stimulation of the lactate production. Quercetin itself enhanced the ATPase activity but did not affect the lactate formation. Apigenin (1.5 μm) enhanced reliably the lactate generation, but it did not exert any effect on the ATPase activity. High concentration of ascorbic acid (60 mm) did not change the Lf stimulatory effect on Na+/K+-ATPase, but decreased the Lf-specific-binding. A significantly strong inhibitory effect on the Lf-specific binding exerted the electron acceptors NAD+ (2 mm) and FAD (2 mm). These effects concern most likely the competition with Lf for electron(s) which is (are) provided from the erythrocyte intercellular electron transport chain(s).

scholarly journals BDNF-TrkB signaling interacts with the GABAergic system to inhibit rhythmic swallowing in the rat

2008 ◽  
Vol 295 (4) ◽  
pp. R1050-R1059 ◽  
Author(s):  
Bruno Bariohay ◽  
Catherine Tardivel ◽  
Juliette Pio ◽  
André Jean ◽  
Bernadette Félix
Keyword(s):  
Superior Laryngeal Nerve ◽  
Inhibitory Effect ◽  
Pattern Generator ◽  
Adult Rat ◽  
Trkb Receptors ◽  
Adult Rat Brain ◽  
Motor Component ◽  
Tropomyosin Related Kinase B ◽  
Repetitive Electrical Stimulation ◽  
Stimulation Of

Brain-derived neurotrophic factor (BDNF) acts as an anorexigenic factor in the dorsal vagal complex (DVC) of the adult rat brain stem. The DVC contains the premotoneurons controlling swallowing, a motor component of feeding behavior. Although rats with transected midbrain do not seek out food, they are able to swallow and to ingest food. Because BDNF and tropomyosin-related kinase B (TrkB) receptors are expressed in the DVC, this study hypothesized that BDNF could modify the activity of premotoneurons involved in swallowing. Repetitive electrical stimulation of the superior laryngeal nerve (SLN) induces rhythmic swallowing that can be recorded with electromyographic electrodes inserted in sublingual muscles. We show that a microinjection of BDNF in the swallowing network induced a rapid, transient, and dose-dependant inhibition of rhythmic swallowing. This BDNF effect appeared to be mediated via TrkB activation, since it no longer occurred when TrkB receptors were antagonized by K-252a. Interestingly, swallowing was inhibited when subthreshold doses of BDNF and GABA were coinjected, suggesting a synergistic interaction between these two signaling substances. Moreover, BDNF no longer had an inhibitory effect on swallowing when coinjected with bicuculline, a GABAA receptor antagonist. This blockade of BDNF inhibitory effect on swallowing was reversible, since it reappeared when BDNF was injected 15 min after bicuculline. Finally, we show that stimulation of SLN induced a decrease in BDNF protein within the DVC. Together, our results strongly suggest that BDNF inhibits swallowing via modulation of the GABAergic signaling within the central pattern generator of swallowing.

scholarly journals ATP-dependent interaction of propranolol and local anaesthetic with sarcoplasmic reticulum. Stimulation of Ca2+ efflux

1988 ◽  
Vol 256 (3) ◽  
pp. 733-739 ◽  
Author(s):  
V Shoshan-Barmatz
Keyword(s):  
Sarcoplasmic Reticulum ◽  
Atpase Activity ◽  
Local Anaesthetics ◽  
Inhibitory Effect ◽  
Phospholipid Bilayer ◽  
Drug Induced ◽  
Protein Factor ◽  
Dependent Inhibition ◽  
Drug Modification ◽  
Stimulation Of

Preincubation of sarcoplasmic reticulum (SR) with propranolol or tetracaine inhibits Ca2+ accumulation and stimulates ATPase activity by more than 2-fold. This effect is obtained only when the preincubation is carried out in the presence of ATP or other nucleoside triphosphates. The (ATP + drug)-induced inhibition of Ca2+ accumulation is pH-dependent, increasing as the pH rises above 7.5. The presence of micromolar concentrations of Ca2+ or Mg2+ during the preincubation prevents the inhibitory effect of ATP plus drug on Ca2+ accumulation or ATPase activity. The (ATP + drug) modification of SR vesicles resulted in stimulation of a rapid Ca2+ efflux from passively loaded vesicles. The ATP-dependent inhibition of Ca2+ accumulation by the drug is obtained with other local anaesthetics. The drug concentration required for 50% inhibition was 0.15 mM for dibucaine and 0.4 mM for both propranolol and tetracaine, whereas it was 5 mM, 8 mM and greater than 10 mM for lidocaine, benzocaine and procaine respectively. The heavy SR vesicles were only slightly affected by the incubation with propranolol or tetracaine in the presence of ATP, but their sensitivity increased markedly after storage at 0 degrees C for 24-48 h. These results suggest that propranolol and some local anaesthetics, in the presence of ATP, stimulate Ca2+ efflux by modifying a protein factor(s) rather than the phospholipid bilayer.

Interleukin-1 inhibition of Na(+)-K(+)-ATPase in inner medullary collecting duct cells: role of PGE2

1991 ◽  
Vol 261 (6) ◽  
pp. F1013-F1016 ◽  
Author(s):  
M. L. Zeidel ◽  
H. R. Brady ◽  
D. E. Kohan
Keyword(s):  
Atpase Activity ◽  
Collecting Duct ◽  
Interleukin 1 ◽  
Inhibitory Effect ◽  
Inner Medullary Collecting Duct ◽  
Duct Cells ◽  
Natriuretic Effect ◽  
Collecting Duct Cells ◽  
Medullary Collecting Duct ◽  
Stimulation Of

Interleukin-1 (IL-1), a cytokine produced by macrophages, causes an increase in Na+ excretion in experimental animals. Micropuncture studies have determined that the natriuretic effect of IL-1 is largely due to inhibition of Na+ reabsorption in the collecting duct. The current studies made use of suspensions of rabbit inner medullary collecting duct (IMCD) cells to examine the mechanism by which IL-1 regulates Na+ transport. IL-1 reduced ouabain-sensitive 86Rb+ uptake by 48% at 10 s, 36% at 30 s, and 29% at 60 s, suggesting an inhibitory effect on Na(+)-K(+)-adenosinetriphosphatase (ATPase) activity. IL-1 inhibition of 86Rb+ uptake occurred in a dose-dependent manner. This effect appears to be mediated by prostaglandin E2 (PGE2) because 1) ibuprofen blocks the inhibitory effect of IL-1 on IMCD Na(+)-K(+)-ATPase activity, 2) IL-1 and PGE2 cause equivalent and nonadditive inhibition of 86Rb+ uptake, 3) IL-1 causes a two- to threefold increase in PGE2 content in IMCD cells, and 4) dose-response curves were similar for IL-1 stimulation of PGE2 content and inhibition of 86Rb+ uptake in IMCD cells. Thus the natriuretic effect of IL-1 is due, at least in part, to stimulation of PGE2 production by collecting duct cells with resultant inhibition of Na(+)-K(+)-ATPase activity.

Reduced Mg2+- ATPase Activity in the Hypoglycemic Adult Rat Brain

2001 ◽  
Vol 56 (9-10) ◽  
pp. 912-914 ◽  
Author(s):  
Stylianos Tsakiris ◽  
Christos Koromilas ◽  
Kleopatra H. Schulpis
Keyword(s):  
Atpase Activity ◽  
Rat Brain ◽  
Adult Male ◽  
Enzyme Activities ◽  
Male Rat ◽  
Whole Brain ◽  
Adult Rat ◽  
Adult Rat Brain ◽  
Adult Male Rat

Abstract The effects of different a-D-Glucose (Glu) concentrations (0 -16 mᴍ) on Na+, K+-ATPase and Mg2+-ATPase activities were investigated in homogenates of adult male rat whole brain at 37 °C. The enzyme activities were determined after 1h preincubation with Glu. Brain Na+, K+-ATPase was not affected by Glu different concentrations. On the contrary, Mg2+-ATPase activity was considerably reduced with Glu concentrations lower than 4 mᴍ. The enzyme was inhibited 40%, 50% or 80% with 3, 2 or 1 mᴍ of Glu, respectively. The above results suggest: a) The various concentrations of Glu have no effect on brain Na+, K+-ATPase activity, b) The inhibited brain Mg2+-ATPase in hypoglycemia produces low intracellular Mg2+, which could modulate the activity of Mg2+ -dependent enzymes and the rates of protein syn­thesis and growth of the cell.

scholarly journals Distributions of choline acetyltransferase and acetylcholinesterase activities in layers of rat superior colliculus.

1985 ◽  
Vol 33 (7) ◽  
pp. 631-641 ◽  
Author(s):  
C D Ross ◽  
D A Godfrey
Keyword(s):  
Superior Colliculus ◽  
Choline Acetyltransferase ◽  
Enzyme Activities ◽  
Ache Activity ◽  
Whole Brain ◽  
Chat Activity ◽  
Caudal Region ◽  
Brain Ache ◽  
Average Activity ◽  
Brain Ache Activity

Choline acetyltransferase (ChAT) and acetylcholinesterase (AChE) activities were assayed in samples dissected from sagittal sections through rat superior colliculus. The magnitude of ChAT activity was about half to equal that found in rat whole brain in all layers except stratum griseum intermediale, where the average activity was higher than whole brain. AChE activity was three to four times that found in rat whole brain in superficial layers and about the same as average brain in deeper layers, except in the statum griseum intermediale, where the average activity was about twice whole brain. Rostral-caudal gradients in both ChAT and AChE activities occurred in stratum griseum intermediale, with activities in the caudal region of some animals as high as four times those in the rostral. ChAT activity in samples associated with locations of patches or spots of AChE staining product in stratum griseum intermediale was significantly higher than in samples from "nonpatch" regions. Results are discussed relative to inputs into the colliculus, whose terminations may correlate in location with the distributions of the enzyme activities.

ʟ-Phenylalanine Effect on Rat Brain Acetylcholinesterase and Na+,K+-ATPase

1998 ◽  
Vol 53 (3-4) ◽  
pp. 163-167 ◽  
Author(s):  
Stylianos Tsakiris ◽  
Panagiota Kouniniotou-Krontiri ◽  
Kleopatra H. Schulpis ◽  
John C. Stavridis
Keyword(s):  
Enzyme Activity ◽  
Cerebral Cortex ◽  
Atpase Activity ◽  
Direct Effect ◽  
Indirect Effect ◽  
Ache Activity ◽  
Brain Homogenate ◽  
Activity Increase ◽  
Low Concentrations ◽  
Brain Acetylcholinesterase

Abstract The effect of different L-phenylalanine (Phe) concentrations (0 .1-12.1 mᴍ) , on acetylcholinesterase (AChE ) and Na+,K+-ATPase activities of brain homogenate and pure enzymes, was investigated at 37 °C. AChE and Na+,K+-ATPase activities were determined according to Ellman G. L., Courtney D., Andres V. and Featherstone R. M. (1961), Biochem. Pharmacol. 7, 88 - 95 and Bowler K. and Tirri R. (1974), J. Neurochem. 23, 611-613 ) respectively, after preincubation with Phe. AChE activity in brain homogenate or in pure eel E.electricus enzyme showed a decrease, which reached up to 18% with concentrations of 0.9-12.1 mᴍ. Brain homogenate Na+,K+-ATPase activity showed an increase 16-65% with 0.24-0.9 mᴍ of Phe, while an activity increase of 60 -65% appeared with 0.9-12.1 mᴍ of Phe. Pure enzyme activity (from porcine cerebral cortex) was not affected by high Phe concentrations, while it was increased by low concentrations. The above results suggest: a) A direct effect of Phe on AChE, b) A direct effect of low Phe concentrations and an indirect effect of high ones on Na+,K+-ATPase.

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