Morphological and biochemical investigation into the possible neuroprotective effects of kolaviron (Garcinia kola bioflavonoid) on the brains of rats exposed to vanadium

In this study, the morphological and biochemical susceptibility of the rat brain to vanadium, in the form of sodium metavanadate, and the comparative ameliorative effect of Garcinia kola and kolaviron (G. kola extract), was examined. Brain regions examined were the cerebrum, cerebellum, hippocampus and the olfactory bulb. We showed that vanadium administration caused cellular vacuolation, congestion, and Purkinje cell degeneration and a marked reduction in myelin tracts. Biochemical tests revealed increased lipid peroxidation induced by vanadium, which was ameliorated with the administration of G. kola and kolaviron. Vanadium administration caused an increase in thiobarbituric acid–reactive substances (TBARS) in the cerebrum and hippocampus, whereas the administration of kolaviron resulted in a reduction of the TBARS level by 65.7 and 80%, respectively, in the regions aforementioned. Also, the administration of kolaviron resulted in an increased activity of superoxide dismutase (61.24%) in all brain regions assessed, when compared with the group administered vanadium alone. Results obtained from this study led to the conclusion that kolaviron reduces vanadium-induced oxidative stress in the brain.     

Hepatoprotection of D-galactosamine-induced toxicity in mice by purified fractions from Garcinia kola seeds

The hepatoprotective effect of a biflavonoid complex, kolaviron, and its fractions from Garcinia kola seeds, together with the possible mechanisms involved was investigated in mice intoxicated with a single dose of D-galactosamine (GalNH(2)). Likewise, the ability of vitamin E to attenuate the toxicity was examined. Kolaviron, was separated by thin-layer chromatographic technique into three fractions; Fraction I, Fraction II and Fraction III with RF values of 0.48, 0.71 and 0.76, respectively. Pretreatment with kolaviron, fraction I and fraction II at a dose of 100 mg/kg for seven consecutive days before challenge with a single dose of GalNH(2) (800 mg/ kg) significantly (P<0.05) decreased serum alanine (ALT) and aspartate (AST) aminotransferases by 67%, 70%, 71% and 39%, 35%, 46%, respectively over GalNH(2)-only intoxicated mice. Vitamin E elicited respectively 65% and 39% reduction in the GalNH(2)-induced increase in the activities of these enzymes. In addition, pretreatment with kolaviron and fraction II significantly (P<0.05) decreased the activity of microsomal gamma-glutamyl transferase (gamma-GT) by 42% and 46%, respectively. Administration of kolaviron to GalNH(2)-intoxicated mice also restored glucose-6-phosphatase to level that was comparable to the control (P<0.05). These extracts except fraction III prevented the accumulation of serum and microsomal lipid peroxidation products, and also prevented the depletion of reduced glutathione (GSH) levels in the liver of GalNH(2)-intoxicated mice. Kolaviron, fraction I and fraction II at a dose of 100 mg/kg caused an induction of glutathione-S-transferase (GSH transferase) and uridyl glucuronosyl transferase (UDPGT) activities by 31%, 34%, 35% and 29%, 65%, 56%, respectively. GalNH(2)-induced toxicity was essentially prevented as indicated by a liver histopathologic study of liver slices from mice pretreated with kolaviron, fraction I and fraction II. This study shows that treatment with kolaviron, fraction I and fraction II (purified fractions from Garcinia kola) appeared to enhance the recovery from GalNH(2)-induced hepatotoxicity, and that the fractions I and II may therefore be responsible for the observed antihepatotoxic effect of kolaviron. This protection may be due to the ability of these extracts to induce the expression of phase II drug metabolizing enzymes.     

Chemoprotection of ethylene glycol monoethyl ether-induced reproductive toxicity in male rats by kolaviron, isolated biflavonoid from Garcinia kola seed

The present study investigated the protective effect of kolaviron, a biflavonoid from the seed of Garcinia kola, on ethylene glycol monoethyl ether (EGEE)-induced reproductive toxicity in male rats. The protective effect of kolaviron was validated using vitamin E, a standard antioxidant. EGEE was administered at a dose of 200 mg/kg. Other groups of rats were simultaneously treated with kolaviron (100 and 200 mg/kg) and vitamin E (50 mg/kg) for 14 days. EGEE treatment resulted in significant decrease in glutathione (GSH) level, superoxide dismutase (SOD), catalase (CAT) and glutathione peroxidase (GPx) activities but markedly increased the glutathione-S-transferase (GST) and lactate dehydrogenase (LDH) activities in the testes. In the spermatozoa, administration of EGEE caused significant decrease in the activities of CAT, GPx, GST and LDH as well as in the level of GSH but significantly increased SOD activity with concomitant increase in hydrogen peroxide and malondialdehyde levels in both testes and spermatozoa. EGEE-exposed rats showed marked testicular degeneration with concomitant decrease in spermatozoa quantity and quality. Overall, EGEE causes reproductive dysfunction in rats by altering antioxidant systems in the testes and spermatozoa. Kolaviron or vitamin E exhibited protective effects against EGEE-induced male reproductive toxicity by enhancement of antioxidant status and improvement in spermatozoa quantity and quality.     

Chemoprevention of 2-acetylaminofluorene-induced hepatotoxicity and lipid peroxidation in rats by kolaviron--a Garcinia kola seed extract.

The effect of kolaviron, a mixture of Garcinia biflavonoid 1 (GB1), Garcinia biflavonoid 2 (GB2) and kolaflavanone, used in the treatment of various ailments in southern Nigeria on hepatotoxicity and lipid peroxidation induced by 2-acetylaminofluorene (2-AAF) in rats was investigated. The ability of butylated hydroxyanisole (BHA) to attenuate the toxic effect of 2-AAF was also examined. Kolaviron administered orally to rats at a dose of 100mg/kg body weight twice a day for 1 week before challenge with 2-AAF (200mg/kg feed) and continuously for 3 weeks at a single dose of 200mg/kg body weight reversed the 2-AAF-mediated decrease in final body weight and relative organ weights, especially the liver. BHA was administered at a dose of 7.5g/kg feed to the animals for 4 weeks. The extract decreased significantly the 2-AAF-mediated increase in the activity of aspartate aminotransferase, alanine aminotransferase, gamma-glutamyl transferase and ornithine carbamyl transferase by 58%, 62%, 60% and 67%, respectively. BHA elicited respectively 55%, 63%, 57% and 65% reduction in the 2-AAF induced-increase in the activities of these enzymes. Histological examination of the liver slices correlated with the changes in serum enzyme alterations. Similarly, kolaviron decreased the 2-AAF reduction of 5'-nucleotidase and glucose-6-phosphatase activities by 63% and 60%, respectively while BHA elicited 59% and 61% decrease in the activities of these enzymes. Simultaneous administration of kolaviron with 2-AAF inhibited microsomal lipid peroxidation as assessed by the thiobarbituric acid reacting substances (TBARS) formation by 66%. BHA produced a 64% reduction in TBARS formation. In the present study, kolaviron appears to act as an in vivo natural antioxidant and an effective hepatoprotective agent and is as effective as BHA.     

Kolaviron,a Natural Antioxidant and Anti‐Inflammatory Phytochemical Prevents Dextran Sulphate Sodium‐Induced Colitis in Rats

The beneficial effects of kolaviron, a natural biflavonoid from the seeds of Garcinia kola, have been attributed mainly to its antioxidant and anti‐inflammatory effects. This study investigated these effects on dextran sulphate sodium (DSS)‐induced ulcerative colitis in rats. Sulfasalazine served as standard reference in this study. Kolaviron and sulfasalazine were separately co‐administered orally at 200 mg/kg and 500 mg/kg, respectively, to dextran sulphate sodium‐exposed rats for 5 days. The result indicated that kolaviron or sulfasalazine significantly prevented DSS‐induced body weight loss as well as the incidence of diarrhoea and bleeding in DSS‐exposed rats. Kolaviron suppressed the DSS‐mediated increase in colonic nitric oxide concentration and myeloperoxidase activity and significantly prevented the increase in inflammatory mediators, interleukin‐1β and tumour necrosis factor alpha, in the colon of DSS‐treated rats. The significant depletion in colonic antioxidant status in rats exposed to DSS alone was evident by marked reduction in colonic catalase and glutathione S‐transferase activities as well as glutathione content, leading to elevated hydrogen peroxide and lipid peroxidation levels. Histopathologically, DSS alone resulted in severe epithelial erosion, total absence of goblet cells, destruction of the crypts, necrotic and distorted glands, accompanied by marked cellular mononuclear cells infiltration. However, administration of kolaviron and sulfasalazine ameliorated DSS‐induced colitis by increasing the antioxidant status decreased hydrogen peroxide and lipid peroxidation levels and attenuated the adverse effect of DSS on colon architecture. In conclusion, the anti‐colitis effect of kolaviron is related to its intrinsic anti‐inflammatory and anti‐oxidative properties.     

Anti-oxidant mechanisms of kolaviron: studies on serum lipoprotein oxidation, metal chelation and oxidative membrane damage in rats

1. In the present study, we have examined the ability of kolaviron, a natural biflavonoid from Garcinia kola seeds, to prevent the susceptibility of rat serum lipoprotein to undergo oxidative modification in vitro and ex vivo. In addition, its ability to chelate metal ions and mitigate iron/ascorbate-induced damage to microsomal lipids was investigated. 2. Lipoprotein resistance to copper-induced oxidation was highly improved in rats treated with kolaviron (100 mg/kg) for 7 days, as demonstrated by a significant increase in lag time compared with control. A significant (P < 0.05) decrease in area under the curve (AUC) and slope of propagation was observed in kolaviron-treated rats compared with control. Conjugated dienes formed after 240 min of lipoprotein oxidation were markedly decreased in kolaviron-treated rats compared with controls. Malondialdehyde concentrations were significantly reduced in the serum lipoproteins of kolaviron-treated rats with an attendant significant increase in the total anti-oxidant activity compared with control. 3. In vitro, kolaviron (10-60 micromol/L) inhibited the Cu2+-induced oxidation of rat serum lipoprotein in a concentration-dependent manner. Kolaviron, at 20 and 60 micromol/L, produced 48 and 87% inhibition of oxidation of lipoprotein, respectively. Compared with control, kolaviron, at 10 and 20 micromol/L, resulted in 29 and 47% decreases in AUC, respectively. In addition, kolaviron (10 micromol/L) elicited a 53% increase in lag time, whereas 40 and 60 micromol/L kolaviron produced 38 and 88% decreases in slope, respectively. 4. Kolaviron effectively prevented microsomal lipid peroxidation induced by iron/ascorbate in a concentration-dependent manner. Kolaviron at the highest dose tested (90 micromol/L) had a significant chelating effect on Fe2+ (78%). 5. In conclusion, our data demonstrate that kolaviron protects against the oxidation of lipoprotein, presumably by mechanisms involving metal chelation and anti-oxidant activity, and, as such, may be of importance in relation to the development of atherosclerosis.     

Mercury distribution in neonatal rat brain after intrauterine methylmercury exposure

Methylmercuric chloride (MMC) was orally administered to pregnant Wistar rats from gestational day 6 (G6) for 5 consecutive days. After delivery, the neonatal rats were decapitated and the cerebrum, cerebellum and hippocampus were excised on postnatal day (PND) 1, 7, 14, 21, 30 to determine total Hg contents and concentrations (six per stage). Both total Hg contents and concentrations in all the three regions increased as exposure dose increased and declined as postnatal time prolonged. Interestingly, differences of total Hg content between cerebrum and hippocampus at each time-point were significant (P<0.05). In the meantime, considering the Hg concentration, while no differences were observed before PND14 (P<0.05) among the three regions, Hg concentration in hippocampus was significantly higher than in cerebrum after that time period (P<0.05). We demonstrated that MeHg could pass through the placental and blood-brain barriers in a dose-dependent manner. Moreover, we found mercury redistribution occurred in offspring brain following the prolongation of postnatal time. The hippocampus was the major target of MeHg accumulation.     

Acute and chronic morphine treatments and morphine withdrawal differentially regulate GRK2 and GRK5 gene expression in rat brain

Opioid agonist stimulates activation of G protein-coupled receptor kinase (GRK) and causes desensitization of opioid signaling, which plays an important role in opioid tolerance. The current study investigated the potential regulatory effects of acute and chronic morphine administration and withdrawal on GRK2 and GRK5 gene expression in rat brain. Our results showed that the initial morphine treatment (10 mg/kg) significantly increased GRK mRNA levels in cerebral cortex, hippocampus, and lateral thalamic nuclei. A significant decrease in GRK5 mRNA levels was observed in periaqueductal gray. In strong contrast, repeated administration of morphine for 9 days failed to cause any significant increase in GRK5 mRNA in any of these brain regions. Chronic morphine treatment resulted in 30-70% down-regulation of GRK2 expression in cerebral cortex, hippocampus, thalamus, and locus coeruleus, opposite to what observed with the single morphine administration. Moreover, spontaneous and naloxone-precipitated morphine withdrawal resulted in aberrant increases in GRK2 and GRK5 mRNA levels in these brain regions. Taken together, our study suggests that opioid not only induces rapid negative feedback regulation on opioid signals through activation of GRK but also exerts its impact, via controlling levels of GRK gene expression, on the regulatory machinery itself over a longer period of time in brain.     

Kolaviron modulates cellular redox status and impairment of membrane protein activities induced by potassium bromate (KBrO(3)) in rats.

In this study, we examined the modulatory effects of kolaviron, a biflavonoid from Garcinia kola seeds on the antioxidant defense mechanisms, cellular redox status and oxidative stress in the kidney and liver of rats pretreated with potassium bromate (KBrO(3)) intragastrically as a single dose of 300 mg kg(-1)weight for 4 weeks. Treatment of rats with KBrO(3)resulted in an insignificant difference (P> 0.05) in body weight compared to controls. However, a significant increase in kidney/body weight ratio (P< 0.001) was observed in rats treated with KBrO(3)while liver/body weight ratio was not affected. KBrO(3)depressed the activities of superoxide dismutase, glutathione peroxidase and catalase (P< 0.001) in the kidney but not in the liver. Kolaviron (200 mg kg(-1)body weight) administered three times a week for 4 weeks inhibited the decrease mediated by KBrO(3)of these enzymes in the kidney by 29, 88 and 45%, respectively. Similarly, kolaviron reduced the KBrO(3)-induced decrease in the activities of gamma -glutamyltransferase and microsomal Ca(2+)ATPase by 73 and 63% in the kidney. In addition, the extract elicited a 27 and 25% decrease in the KBrO(3)-induced increase in malondialdehyde and lipid hydroperoxide formation in the kidney. Kolaviron also attenuated the KBrO(3)-decreased activities of glucose 6-phosphatase, 5 prime prime or minute nucleotidase and alkaline phosphatase (membrane enzymes) by 72, 57 and 25% respectively. The results of the present investigation indicate the antioxidative effect of kolaviron, a natural antioxidant, on drug-induced kidney toxicity. Kolaviron may therefore intervene in the cellular redox status and depression of membrane protein activities caused by KBrO(3)and other environmental carcinogens in the kidney.     

Morphometric and enzymatic effects of neonatal lead exposure in the rat brain

Lead acetate (7.5 mg/kg ip) was administered to rat pups from birth to 10 days of age. This dose did not impair weight gain or produce overt signs of lead toxicity. The animals were sacrificed at 10, 15, 20, or 30 days of age for enzymatic analysis or morphometric assessment. Thickness of the pyramidal cell layer of the hippocampal formation and of the granular cell layer of the dentate gyrus was measured. The activity of acetylcholinesterase (AChE) and butyrylcholinesterase (BuChE) was determined in homogenates from separate brain regions. Significant (p < 0.05) reductions of AChE activity were produced at 10 days in the hippocampus (40%) and medulla oblongata (17%). Although cerebral AChE was reduced by 17%, the reduction of hippocampal AChE (32%) was not significant nor were decreases in AChE observed in either the cerebellum, midbrain, corpus striatum, or medulla oblongata of 20-day-old lead-treated rats. No inhibition of BuChE activity was observed at 10 days. However, BuChE of the midbrain, hippocampus, and cerebrum of 15-day-old animals was decreased by 32, 37, and 12%, respectively. Similrly, BuChE activity of homogenates from the cerebrum, hippocampus, and midbrain of 20-day-old lead-treated rats was reduced by 35, 35, and 37%, respectively. No significant decreases in AChE or BuChE activity were produced in brain homogenates from 30-day-old animals. Measurements of hippocampal cell layer thickness and distance from the hippocampus to the cerebral cortex indicated that lead administration produced 10–15% reductions in both parameters. The results suggest that lead exposure may produce a reversible impairment of AChE and BuChE in specific brain regions of the developing rat brain. However, morphological effects of lead exposure may persist after the effects on BuChE and AChE activities are no longer discernible.     

Mechanisms for the hepatoprotective action of kolaviron: studies on hepatic enzymes, microsomal lipids and lipid peroxidation in carbontetrachloride-treated rats.

The present work examines the protective mechanisms of a biflavonoid fraction of an extract from Garcinia kola seeds, kolaviron, in rats treated with carbontetrachloride (CCl(4)). CCl(4)administered at a dose of 1.2 g kg(-1), three times a week for 2 weeks, significantly depressed the activities of microsomal aniline hydroxylase, aminopyrine N -demethylase, ethoxyresorufin O -demethylase and p -nitroanisole O -demethylase. Kolaviron (200 mg kg(-1)), administered for 14 days consecutively, inhibited (P<0.001) the CCl(4)mediated decrease in the activities of these enzymes by 60, 65, 55, and 63%, respectively. Kolaviron reduced the CCl(4)increase in the cholesterol/phospholipid ratio. Similarly, kolaviron attenuated the toxic onslaught imposed by CCl(4)on 5'nucleotidase, glucose 6-phosphatase (microsomal marker enzymes) and malondialdehyde formation by 41, 54 and 77%, respectively. Kolaviron elicited 168% and 234% increases in the activity of UDP-glucuronosyl transferase and glutathione S -transferase. Simultaneous administration of kolaviron with CCl(4)modulated the effect of CCl(4)on the activities of these enzymes. On the basis of the above data, it can be postulated that kolaviron exerts its protective action against carcinogen-induced liver damage, first, by acting as an in vivo natural antioxidant and, second, by enhancement of drug-detoxifying enzymes.     

Estrogen protects against brain lipid peroxidation in ethanol-withdrawn rats

This study examined whether 17beta-estradiol (E2) administration protects against ethanol withdrawal (EW)-associated oxidative insults by assessing oxidative markers thiobarbituric-acid-reacting-substances (TBARS). Ovariectomized rats implanted with E2 (EW/E2) or oil pellets (EW/Oil) received chronic ethanol (7.5% wt./vol., 5 weeks) or control dextrin diet (Dextrin/Oil). At 24 or 48 h of EW, rats were tested for overt EW signs and the cerebellum, hippocampus, and cortex were prepared for TBARS assessment in the presence and absence of FeCl3. For control experiments, we assessed E2 effects on blood ethanol concentrations and TBARS levels during ethanol exposure prior to EW. The EW/Oil group showed enhanced endogenous- and FeCl3-stimulated membrane TBARS levels in the cerebellum and hippocampus in a manner inhibited by E2 treatment. There was a relationship between the severity of EW and elevation of TBARS levels, particularly in the cerebellum. The enhanced TBARS levels at 24 h of EW appeared to diminish at 48 h in the hippocampus, but persisted in the cerebellum. E2 treatment did not alter blood ethanol concentrations and ethanol exposure alone did not enhance TBARS levels. These data suggest that EW rather than ethanol enhances brain lipid peroxidation that is transient and brain-region specific. Estrogens protect against the brain lipid peroxidation in a manner independent of blood ethanol concentrations.     

Hypoglycaemic and hypolipidaemic effects of fractions from kolaviron, a biflavonoid complex from Garcinia Kola in streptozotocin-induced diabetes mellitus rats

In the search for natural hypoglycaemic agents as alternatives to synthetic ones that are expensive and not easily accessible, and to justify the use of Garcinia kola seeds in traditional African medicine to treat diabetes, the hypoglycaemic and hypolipidaemic effects of fractions from kolaviron (KV) (a Garcinia kola seed extract) were investigated in normal and streptozotocin (STZ)-diabetic rats. KV, a biflavonoid complex from Garcinia kola seed, was separated by thin-layer chromatography into three fractions; Fraction I (FI), Fraction II (FII) and Fraction III (FIII) with RF values of 0.48, 0.71 and 0.76, respectively. In normoglycaemic rats, KV, FI and FII administered at a dose of 100 mg kg(-1) body weight elicited significant (P < 0.05) hypoglycaemic activity within 4 h of oral administration. Precisely, KV, FI and FII decreased blood glucose levels of normoglycaemic rats by 66%, 50% and 61%, respectively, when compared with controls 30 min after oral administration of the extracts. In hyperglycaemic rats, KV, FI and FII significantly (P < 0.05) reduced blood sugar levels in STZ-diabetic rats within 4 h of oral administration. Furthermore, KV alone produced a significant (P < 0.05) anti-diabetic effect from day 3 to day 7 of oral intubation of STZ-diabetic rats. In addition, the extracts showed favourable effect on the plasma lipid profile of STZ-diabetic rats, and also decreased significantly (P < 0.05) the STZ-induced increase in the activity of microsomal glucose-6-phosphatase and lipid peroxidation (LPO) products. This study confirms the anti-diabetic and hypolipidaemic effects of KV in STZ-diabetic rats. These observed effects of KV are attributed to two of its fractions, FI and FII, with RF values of 0.48 and 0.71, respectively.     

Possible anti-atherogenic effect of kolaviron (a Garcinia kola seed extract) in hypercholesterolaemic rats

1. The hypolipidaemic effect of kolaviron, a mixture of Garcinia biflavonoid 1 (GB1), Garcinia biflavonoid 2 (GB2) and kolaflavanone, used in the treatment of various ailments in southern Nigeria, was investigated in rats. The ability of Questran (Bristol-Myers Squibb, Hounslow, UK), a hypolipidaemic therapeutic drug, to attenuate hypercholesterolaemia in rats was also examined. 2. In order to assess the hypolipidaemic effect of this extract in experimental animals, thiobarbituric acid-reactive substances (TBARS), cholesterol, phospholipid, low-density lipoprotein-cholesterol (LDL-C), high-density lipoprotein-cholesterol and triglyceride levels were determined in the plasma and liver. 3. Cholesterol administered orally to rats at a dose of 30 mg/0.3 mL five times a week for 8 consecutive weeks resulted in a significant increase (P<0.001) in the relative weight of the heart of hypercholesterolaemic animals compared with control. However, cotreatment with kolaviron and Questran ameliorated the cholesterol-induced enlargement of the heart. Kolaviron (100 and 200 mg/kg) elicited 88.5 and 87.4% reductions, respectively, in plasma cholesterol levels of pretreated animals compared with the cholesterol-fed group. In addition, kolaviron produced a significant decrease (P<0.05) in post-mitochondrial fraction (PMF) cholesterol levels in treated animals compared with untreated hypercholesterolaemic animals. Similarly, Questran significantly decreased (P<0.05) the cholesterol-induced increase in plasma cholesterol levels compared with untreated hypercholesterolaemic animals. In addition, (100 and 200 mg/kg) significantly (P<0.05) decreased plasma LDL-C levels by over 70% in treated animals compared with untreated hypercholesterolaemic animals. Similarly, kolaviron significantly decreased (P<0.05) PMF LDL-C levels by over 60% in treated animals compared with untreated hypercholesterolaemic animals. 4. The significantly (P<0.05) higher values of plasma and PMF triglycerides obtained in cholesterol-fed animals compared with control animals were unaltered following cotreatment with kolaviron and Questran. In the present study, there was a significant decrease (P<0.05) in plasma formation of malondialdehyde in kolaviron- and Questran-treated animals compared with untreated hypercholesterolaemic animals. 5. The results of the present study demonstrate that kolaviron exerts a hypocholesterolaemic effect and reduces the relative weight of the heart in cholesterol-fed animals. This reduction and the favourable lipid profile indicate a possible anti-atherogenic property of the extract.     

The biochemical and ultrastructural examinations in central cholinergic damage of the rat induced by the intraperitoneal administration of AF64A

Ethylcholine mustard aziridinium ion (AF64A), a synthesized cholinergic neurotoxin, was administered via intraperitoneal injection to the rat to study its effect on the central cholinergic nervous system. A single or consecutive daily injection of AF64A for 10 days resulted in a persistent reduction of acetylcholine (ACh) content in the several tested regions of the brain in the following order: hippocampus greater than cerebral cortex = striatum, the degree was the greatest in the hippocampus. Both resting and K(+)-stimulated release of ACh from the hippocampus were also significantly reduced 24 hr after a single injection of AF64A. Furthermore, daily injection of AF64A for 10 days induced a significant reduction of choline acetyltransferase (ChAT) activity in the homogenate obtained from the hippocampus but not from the cerebral cortex and striatum. ChAT activity in the crude synaptosomal fraction of the cerebral cortex was also significantly decreased. These results suggest that intraperitoneal administration of AF64A could induce cholinergic hypofunction more selectively in the nerve terminals. The high affinity choline uptake, which is located mainly on cholinergic nerve terminals, was not affected by the administration of AF64A. Any notable changes of ultrastructure in the cholinergic nerve terminals after the administration were not observed in all three regions examined. The present findings suggested that intraperitoneal administration of AF64A induces a specific damage of cholinergic nerve terminals by inhibiting ChAT activity. The cholinergic damage was most prominent in the hippocampus.     

Regional difference of ROS generation, lipid peroxidaton, and antioxidant enzyme activity in rat brain and their dietary modulation

One of the potential causes of age-related neuronal damage can be reactive oxygen species (ROS), as the brain is particularly sensitive to oxidative damage. In the present study, we investigated the effects of aging and dietary restriction (DR) on ROS generation, lipid peroxidation, and antioxidant enzymes in cerebrum, hippocampus, and cerebellum of 6-, 12-, 18-, and 24-month-old rats. ROS generation significantly increased with age in cerebrum of ad libitum (AL) rats. However, no significant age-difference was observed in hippocampus and cerebellum. DR significantly decreased ROS generation in cerebrum and cerebellum at 24-months. On the other hand, the increased lipid peroxidation of AL rats during aging was significantly reduced by DR in all regions. Our results further showed that catalase activity decreased with age in cerebellum of AL rats, which was reversed by DR, although SOD activity had little change by aging and DR in all regions. In a similar way, glutathione (GSH) peroxidase activity increased with age in cerebrum of AL rats, while DR suppressed it at 24-months. These data further support the evidence that the vulnerability to oxidative stress in the brain is region-specific.     

Curcumin and kolaviron ameliorate di-n-butylphthalate-induced testicular damage in rats

The present study was carried out to evaluate the ameliorative effects of kolaviron (a biflavonoid from the seeds of Garcinia kola) and curcumin (from the rhizome, Curcuma longa L.) on the di-n-butylphthalate (DBP)-induced testicular damage in rats. Administration of DBP to rats at a dose of 2 g/kg for 9 days significantly decreased the relative testicular weights compared to the controls, while the weights of other organs remained unaffected. Curcumin or kolaviron did not affect all the organ weights of the animals. While only DBP treatment significantly increased the testicular malondialdehyde level and gamma-glutamyl transferase activity (gamma-GT), it markedly decreased glutathione level, the testicular catalase, glucose-6-phosphate dehydrogenase, superoxide dismutase, sperm gamma-GT activities and serum testosterone level compared to the control group. Data on cauda epididymal sperm count and live/dead ratio were not significantly affected in the DBP-treated rats. Alone, DBP treatment resulted in a 66% decrease in spermatozoa motility and a 77% increase in abnormal spermatozoa in comparison to control. DBP-treated rats showed marked degeneration of the seminiferous tubules with necrosis and defoliation of spermatocytes. The DBP-induced injuries in biochemical, spermatological parameters and histological structure of testis were recovered by treatment with kolaviron or curcumin. The pattern in the behaviour of these compounds might be correlated with their structural variations. Our results indicate that kolaviron and curcumin protect against testicular oxidative damage induced by DBP. The chemoprotective effects of these compounds may be due to their intrinsic antioxidant properties and as such may prove useful in combating phthalate-induced reproductive toxicity.     

Impact of 70% nitrous oxide administration on regional distribution of brain blood flow in unmedicated healthy swine

Regional distribution of brain blood flow was examined in 11 healthy, spontaneously breathing swine using 15 micron in diameter radionuclide-labeled microspheres that were injected into the left atrium. Measurements were made during inhalation of 30% O2/70% nitrogen (control) and at 15, 45, 75, and 120 min of 30% O2/70% nitrous oxide breathing. The animals were surgically prepared 10-12 days before the hemodynamic study. Arterial blood-gas tensions, arterial pH, mean aortic pressure, and cardiac output remained near their respective control values during exposure to 70% nitrous oxide. Control values of blood flow in the cerebrum, cerebellum, and the brain stem were 68.5 +/- 4.7, 75.6 +/- 4.2, and 54.2 +/- 4.0 ml . min-1 X 100 g-1, respectively. At 15 min of exposure to nitrous oxide, blood flow in the cerebrum, cerebellum, and the brain stem was 169, 127, and 145% of the control values, respectively. For the caudate nuclei and the corpus callosum, the corresponding figures were 141 and 131% of control, while that for remainder of the cerebrum was 178% of the control value. In the medulla, pons, and thalamus-midbrain, blood flow was 151, 157, and 141% of the respective control values. In all regions of the porcine brain, elevated levels of blood flow persisted throughout the 2 h of exposure to 70% nitrous oxide and no marked fluctuations occurred. It is concluded that administration of 70% nitrous oxide to healthy pigs caused pronounced cerebrovascular vasodilatation in all regions of the brain. This persisted throughout the 2 h of its administration.     

3,4-Methylenedioxymethamphetamine enhances the release of acetylcholine in the prefrontal cortex and dorsal hippocampus of the rat

Rationale The neurochemical effects produced by acute administration of 3,4-methylenedioxymethamphetamine (MDMA) on the monoaminergic systems in the brain are well documented; however, there has been little consideration of the potential effects of MDMA on other neurotransmitter systems. Objective The present study was designed to investigate the acute effect of MDMA on cholinergic neurons by measuring acetylcholine (ACh) release in the medial prefrontal cortex (PFC) and dorsal hippocampus, terminal regions of cholinergic projection neurons originating in the basal forebrain. Methods In vivo microdialysis and high-performance liquid chromatography with electrochemical detection (HPLC-ED) were used to assess the effects of MDMA on the extracellular concentration of ACh in the PFC and dorsal hippocampus of the rat. Results The systemic administration of MDMA (3–20 mg/kg, i.p.) resulted in an increased extracellular concentration of ACh in the PFC and dorsal hippocampus. Reverse dialysis of MDMA (100 μM) into the PFC and hippocampus also increased ACh release in these brain regions. Treatment with parachlorophenylalanine and α-methyl-para-tyrosine, inhibitors of serotonin (5-HT) and dopamine (DA) synthesis, respectively, significantly attenuated the release of ACh stimulated by MDMA in the PFC, but not in the dorsal hippocampus. Conclusions MDMA exerts a stimulatory effect on the release of ACh in the PFC and dorsal hippocampus in vivo, possibly by mechanisms localized within these brain regions. In addition, these results suggest that the MDMA-induced release of ACh in the PFC involves both serotonergic and dopaminergic mechanisms.     

Neurochemical changes on oxidative stress in rat hippocampus during acute phase of pilocarpine-induced seizures

Using the epilepsy model obtained by systemic administration of pilocarpine in rats in the present study we investigated the changes caused by seizures on content and species of gangliosides and phospholipids, as well as on cholesterol concentration, glutathione reduced contents, Na⁺, K⁺-ATPase activity and lipid peroxidation levels in rat hippocampus. Wistar rats received pilocarpine hydrochloride (400 mg/kg, i.p., pilocarpine group), and other group received 0.9% saline (i.p., control group). Results showed that seizures significantly decreased the total content of lipids and glutathione reduced concentration in rat hippocampus. We also observed that seizures significantly reduced the absolute quantity of the major brain gangliosides (GM1, GD1a, GD1b and GT1b) and phospholipids (sphingomyelin, phosphatidylcholine and phosphatidylethanolamine). Our data also showed a decreased Na⁺, K⁺-ATPase activity and an increased TBARS levels in hippocampus of seized rats. If confirmed in human beings, these data could suggest that the alteration in lipid composition, Na⁺, K⁺-ATPase activity, glutathione reduced content and TBARS levels caused by seizures might contribute to the neurophysiopathology of seizures observed in epileptic patients.