Schinus terebinthifolius administration prevented behavioral and biochemical alterations in a rotenone model of Parkinson's disease

ABSTRACT Parkinson's disease is a neurodegenerative disorder characterized by motor impairment, cognitive decline and psychiatric symptoms. Schinus terebinthifolius Raddi, Anacardiaceae, had been studied for its anti-inflammatory and antioxidant properties, and in this study, the stem bark was evaluated for the neuroprotective effects on behavioral and biochemical alterations induced by administrations of rotenone in rats. Behavioral evaluations were performed using open-field and rotarod. The in vitro and in vivo antioxidant activities were determined by the DPPH radical scavenging activity and lipid peroxidation method respectively. The administration of rotenone (3 mg/kg, s.c.) produced hypolocomotion, increase of immobility and muscle incoordination, while the treatment with S. terebinthifolius stem bark extract (150, 300 and 600 mg/kg p.o.) for seven days prevented rotenone-induced dysfunctional behavior. Biochemical analysis of the substantia nigra, striatum and cortex revealed that rotenone administration significantly increased lipid peroxidation, which was inhibited by treatment with all doses of S. terebinthifolius. The results suggested neuroprotective effect of S. terebinthifolius possibly mediated through its antioxidant activity, indicating a potential therapeutic benefit of this species in the treatment of Parkinson's disease.

Mitochondrial involvement in carbachol-induced intracellular Ca2+ mobilization and contraction in rat gastric smooth muscle.

AIMS: Mitochondria are important modulators of Ca2+ homeostasis. However, it is not clear if they modulate and participate in smooth muscle signaling and contraction. The aim of the present work was to investigate the role of mitochondria in Ca2+ transients and contraction induced by metabotropic muscarinic receptor activation in rat gastric smooth muscle. MAIN METHODS: Carbachol (CCh)-induced contraction was investigated in the absence or presence of increasing concentration of mitochondrial protonophore, carbonyl cyanide p-(trifluoro-methoxy)phenyl-hydrazone (FCCP), in gastric fundus strips. Ca2+ and mitochondrial membrane potential (ΔΨm) measurements were performed in primarily cultured gastric smooth muscle cells loaded with FURA-2 or TMRE dyes. KEY FINDINGS: Results show that CCh (1 µM)-induced contraction was inhibited by FCCP in a concentration-dependent manner. In cultured smooth muscle cells CCh (1 µM) caused a cytosolic Ca2+ rise. Preincubation with FCCP strongly inhibited CCh-evoked Ca2+ transients indicating that mitochondria shape intracellular Ca2+ signals. CCh induced elevations of ∆Ψm in 60% of the individual mitochondrion analyzed. SIGNIFICANCE: Taken together our results indicate that CCh induces release of Ca2+ from intracellular stores, which may be modulated by mitochondria. Thus, mitochondria participate of the intracellular Ca2+ homeostasis in muscarinic contraction in gastric fundus smooth muscle.

Acute and subacute toxicity of Cassia occidentalis L. stem and leaf in Wistar rats.

ETHNOPHARMACOLOGICAL RELEVANCE: Cassia occidentalis L. (syn. Senna occidentalis; Leguminosae) has been used as natural medicine in rainforests and tropical regions as laxative, analgesic, febrifuge, diuretic, hepatoprotective, vermifuge and colagogo. Herein, we performed a pre-clinical safety evaluation of hydroalcoholic extract of Cassia occidentalis stem and leaf in male and female Wistar rats. MATERIALS AND METHODS: In acute toxicity tests, four groups of rats (n=5/group/sex) were orally treated with doses of 0.625, 1.25, 2.5 and 5.0 g/kg and general behavior, adverse effects and mortality were recorded for up to 14 days. In subacute toxicity assays, animals received Cassia occidentalis by gavage at the doses of 0.10, 0.50 or 2.5 g/kg/day (n=10/group/sex) for 30 days and biochemical, hematological and morphological parameters were determined. RESULTS: Cassia occidentalis did not produce any hazardous symptoms or death in the acute toxicity test, showing a LD(50) higher than 5 g/kg. Subacute treatment with Cassia occidentalis failed to change body weight gain, food and water consumption and hematological and biochemical profiles. In addition, no changes in macroscopical and microscopical aspect of organs were observed in the animals. CONCLUSIONS: Our results showed that acute or subacute administration of Cassia occidentalis is not toxic in male and female Wistar rats, suggesting a safety use by humans.

Adaptive expression pattern of different proteins involved in cellular calcium homeostasis in denervated rat vas deferens.

The activity and protein expression of plasma membrane and sarco(endo)plasmic reticulum (Ca2+-Mg2+)ATPases and ryanodine receptors were investigated in surgically denervated rat vas deferens. The function of thapsigargin-sensitive but not thapsigargin-resistant (Ca2+-Mg2+)ATPase (from sarco(endo)plasmic reticulum and plasma membrane, respectively), evidenced by enzyme activity and Ca2+ uptake experiments, was significantly depressed by 30-50% when compared to innervated vas. Western blots showed that such reduction in sarco(endo)plasmic reticulum (Ca2+-Mg2+)ATPase performance was accompanied by a decrement of similar magnitude in sarco(endo)plasmic reticulum (Ca2+-Mg2+)ATPase type 2 protein expression, without any significant change in plasma membrane (Ca2+-Mg2+)ATPase expression. Finally, [3H]ryanodine binding revealed that the density of ryanodine binding sites was reduced by 45% after denervation without modification in affinity. The present findings demonstrate that sarco(endo)plasmic reticulum proteins involved in intracellular calcium homeostasis are clearly down-regulated and brings further evidence of a modified calcium translocation in denervated rat vas deferens.

Role of noradrenaline on the expression of the Na+/K+-ATPase alpha2 isoform and the contractility of cultured rat vas deferens.

Rat vasa deferentia were cultured for 3 days in Dulbecco's modified Eagle's medium in the absence or presence of 1 microM noradrenaline (NA) to investigate if the lack of NA release is the key factor to explain the selective reduction of the Na(+)/K(+)-ATPase alpha(2) isoform previously observed after in vivo denervation of this organ (Quintas et al., Biochem Pharmacol 2000;60:741-7). The lack of effects of the indirect sympathomimetic tyramine and the neuronal amine uptake blocker cocaine on NA curves indicated that cultured organs were denervated completely. Organ culture induced supersensitivity, expressed as a 6.3-fold increase of pD(2) and a 42% elevation of maximal contraction for NA but not for Ba(2+). Western blotting indicated that the level of the alpha(1) isoform of Na(+)/K(+)-ATPase was unchanged after organ culture, but the alpha(2) isoform was down-regulated drastically to levels that were barely detectable. The addition of NA to the culture medium did not prevent the reduction of alpha(2) expression although it did impede NA supersensitivity (in fact a 4-fold decrease of pD(2) and a 32% reduction of maximal response were observed after incubation in the presence of NA). A striking reduction of L-type Ca(2+) channel expression also was observed, indicated by an 85% decrease of [3H]isradipine binding sites. These data suggest that NA is a trophic factor relevant to the control of muscle contraction, mediated by alpha(1)-adrenoceptors, but not to the expression of either Na(+)/K(+)-ATPase or the L-type Ca(2+) channel.

Up-regulation of Ca(2+) channels in vas deferens after chronic treatment of newborn rats with nifedipine.

Radioligand binding and contraction techniques were used to verify if L-type Ca(2+) channels are modified in rat vas deferens after treatment with the blocker nifedipine (15 microg), injected at 7, 14, 21 and 28 days after birth. Vas deferens tissue was used 10, 30 and 90 days after the last injection, to verify if modifications are persistent. Binding studies with cell membranes, using [(3)H]isradipine, showed an increase of the density (B(max)) of Ca(2+) channels by more than 60%, after 10 and 30 days, without changes of affinity (K(d)). Maximal contractions (E(max)) of KCl, were increased by 106% and 37%, respectively, after 10 and 30 days, without changes of apparent affinity (pD(2)). After 90 days, the values of B(max), K(d), E(max) and pD(2) were not different from the controls. Differences were also not found for rats injected when adult. It is concluded that treatment of newborn, but not of adult, rats with nifedipine produced a long-lasting, though reversible, up-regulation of L-type Ca(2+) channels.