Temperature dependence of the ATP-ase activities in brain homogenates during the postnatal development of the rat

Memory Improvement Effect of Ethanol Garlic (A. sativum) Extract in Streptozotocin-Nicotinamide Induced Diabetic Wistar Rats Is Mediated through Increasing of Hippocampal Sodium-Potassium ATPase, Glutamine Synthetase, and Calcium ATPase Activities

Studies suggest that garlic (A. sativum) improves memory dependent on the hippocampus. However, the effect of ethanol garlic extract on hippocampus Na⁺/K⁺ ATPase, Ca²⁺ ATPase, and glutamine synthetase (GS) activities as possible mechanisms in memory improvement in diabetic Wistar rats has not been reported. Twenty-four male Wistar rats weighing 200-250 g were divided into three groups with 8 rats each. Group (A), normal control rats, and Group (B), diabetic rats, received 1 ml of normal saline; diabetic rats in Group (C) received 1000 mg/kg of garlic extract orally for 21 days. Hyperglycemia was induced by a single intraperitoneal injection of streptozotocin 60 mg/kg followed by 120 mg/kg nicotinamide while extraction of garlic was done by cold maceration method. Memory was tested in all groups. After that, the rats were sacrificed, the brain was removed, and the hippocampi were carefully excised and then homogenized. Activities of Na⁺/K⁺ ATPase, calcium ATPase, and GS were analyzed from the homogenate. Results showed improvement in memory and a significant increase (P < 0.05) in hippocampus Na⁺/K⁺ ATPase, Ca²⁺ ATPase, and GS activities in diabetic rats treated with garlic extract. In conclusion, the increased activity of hippocampus Na⁺/K⁺ ATPase, calcium ATPase, and glutamine synthetase may account for the memory improvement.

Role of Lactobacillus plantarum MTCC1325 in membrane-bound transport ATPases system in Alzheimer's disease-induced rat brain

Introduction: Alzheimer’s disease (AD) is a neurodegenerative disorder, clinically characterized by memory dysfunction and progressive loss of cognition. No curative therapeutic or drug is available for the complete cure of this disease. The present study was aimed to evaluate the efficacy of Lactobacillus plantarum MTCC1325 in ATPases activity in the selected brain regions of rats induced with Alzheimer’s.

Methods: For the study, 48 healthy Wistar rats were divided into four groups: group I as control group, group II as AD model (AD induced by intraperitoneal injection of D-Galactose, 120 mg/kg body weight for 6 weeks), group III as normal control rats which were orally administered only with L. plantarum MTCC1325 for 60 days, and group IV where the AD-induced rats simultaneously received oral treatment of L. plantarum MTCC1325 (10ml/kg body weight, 12×10⁸ CFU/mL) for 60 days. The well known membrane bound transport enzymes including Na⁺, K⁺-ATPases, Ca²⁺-ATPases, and Mg²⁺-ATPases were assayed in the selected brain regions of hippocampus and cerebral cortex in all four groups of rats at selected time intervals.

Results: Chronic injection of D-Galactose caused lipid peroxidation, oxidative stress, and mitochondrial dysfunction leading to the damage of neurons in the brain, finally bringing a significant decrease (-20%) in the brain total membrane bound ATPases over the controls. Contrary to this, treatment of AD-induced rats with L. plantarum MTCC1325 reverted all the constituents of ATPase enzymes to near normal levels within 30 days.

Conclusion: Lactobacillus plantarum MTCC1325 exerted a beneficial action on the entire ATPases system in AD-induced rat brain by delaying neurodegeneration.

Heterogeneous Na+ sensitivity of Na+,K(+)-ATPase isoenzymes in whole brain membranes

The Na+ sensitivity of whole brain membrane Na+,K(+)-ATPase isoenzymes was studied using the differential inhibitory effect of ouabain (alpha 1, low affinity for ouabain; alpha 2, high affinity; and alpha 3, very high affinity). At 100 mM Na+, we found that the proportion of isoforms with low, high, and very high ouabain affinity was 21, 38, and 41%, respectively. Using two ouabain concentrations (10(-5) and 10(-7) M), we were able to discriminate Na+ sensitivity of Na+,K(+)-ATPase isoenzymes using nonlinear regression. The ouabain low-affinity isoform, alpha 1, exhibited high Na+ sensitivity [Ka of 3.88 +/- 0.25 mM Na+ and a Hill coefficient (n) of 1.98 +/- 0.13]; the ouabain high-affinity isoform, alpha 2, had two Na+ sensitivities, a high (Ka of 4.98 +/- 0.2 mM Na+ and n of 1.34 +/- 0.10) and a low (Ka of 28 +/- 0.5 mM Na+ and an n of 1.92 +/- 0.18) Na+ sensitivity activated above a threshold (22 +/- 0.3 mM Na+); and the ouabain very-high-affinity isoform, alpha 3, was resolved by two processes and appears to have two Na+ sensitivities (apparent Ka values of 3.5 and 20 mM Na+). We show that Na+ dependence in the absence of ouabain is the result of at least of five Na+ reactivities. This molecular functional characteristic of isoenzymes in membranes could explain the diversity of physiological roles attributed to isoenzymes.