Mitochondrial calcium, oxidative stress and apoptosis in a neurodegenerative disease model induced by 3-nitropropionic acid

Intracellular calcium homeostasis is important for cell survival. However, increase in mitochondrial calcium (Ca-m(2+)) induces opening of permeability transition pore (PTP), mitochondrial dysfunction and apoptosis. Since alterations of intracellular Ca2+ and reactive oxygen species (ROS) generation are involved in cell death, they might be involved in neurodegenerative processes such as Huntington's disease (HD). HD is characterized by the inhibition of complex II of respiratory chain and increase in ROS production. in this report, we studied the correlation between the inhibitor of the complex II, 3-nitropropionic acid (3NP), Ca2+ metabolism, apoptosis and behavioural alterations. We showed that 3NP (1 mM) is able to release Ca-m(2+), as neither Thapsigargin (TAP, 2 muM) nor free-calcium medium affected its effect. PTP inhibitors and antioxidants inhibited this process, suggesting an increase in ROS generation and PTP opening. in addition, 3NP (0.1 mM) also induces apoptotic cell death. Behavioural changes in animals treated with 3NP (20 mg/kg/day for 4 days) were also attenuated by pre- and co-treatment with vitamin E (VE, 20 mg/kg/day). Taken together, our results show that complex II inhibition could involve Ca-m(2+) release, oxidative stress and cell death that may precede motor alterations in neurodegenerative processes such as HD

Bovine brain phosphatidylserine attenuates scopolamine induced amnesia in mice

This study verifies the effects of bovine brain phosphatidylserine (PS) on passive avoidance (PA) and contextual fear conditioning (CFC) tests in scopolamine-treated mice. Mice received daily i.p. 50 mg/kg PS or 0.2 M Tris pH 7.4 (TRIS) for 5 days. On day 6, mice received saline (TRIS-SAL and PS-SAL) or 1 mg/kg SCO (TRIS-SCO and PS-SCO) i.p. After 20 min, the animals were submitted to PA (experiment 1) or CFC (experiment 2) training sessions, and tests were performed 24 h later. Latency in entering the dark chamber of the PA apparatus presented by TRIS-SCO (but not PS-SCO) group in the test was significantly higher than those presented by controls. Except for TRIS-SCO, all the groups presented higher latencies in the test compared to the training session. in experiment 2, the TRIS-SCO (but not PS-SCO) group presented significantly lower freezing duration than that presented by the TRIS-SAL group in the test. Animals treated with PS alone presented higher freezing duration than that presented by the TRIS-SAL group. the results demonstrate that PS attenuates SCO-induced amnesia in both PA and CFC tests. in addition, PS per se improves retention in the CFC test. (c) 2006 Elsevier Inc. All rights reserved.Universidade Federal de São Paulo, Dept Pharmacol, BR-04023062 São Paulo, BrazilUniversidade Federal de São Paulo, Dept Pharmacol, BR-04023062 São Paulo, BrazilWeb of Scienc

Behavioral evidence of D-1 dopamine receptor supersensitivity induced by paradoxical sleep deprivation in mice

Universidade Federal de São Paulo, São Paulo, BrazilUniversidade Federal de São Paulo, EPM, São Paulo, BrazilWeb of Scienc