Pilocarpine-induced status epilepticus in rats: lipid peroxidation level, nitrite formation, GABAergic and glutamatergic receptor alterations in the hippocampus, striatum and frontal cortex

The aim of the study was to investigate the lipid peroxidation levels, nitrite formation, GABAergic and glutamatergic receptor densities in the hippocampus, frontal cortex and striatum of Wistar rats after seizures and status epilepticus (SE) induced by pilocarpine. The control group was treated with 0.9% saline and sacrificed 1 h after the treatment. One group of rats was administered with pilocarpine (400 mg/kg sc) and sacrificed 1 h after treatment. The result shows that pilocarpine administration and the resulting SE produced a significant increase of lipid peroxidation level in the hippocampus (46%), striatum (25%) and frontal cortex (21%). In nitrite formation, increases of 49%, 49% and 75% in hippocampus, striatum and frontal cortex, respectively, was observed. Pilocarpine treatment induced down-regulation of GABAergic receptors in the hippocampus (38%), striatum (15%) and frontal cortex (11%). However, with regard to glutamatergic receptor densities, increases in the hippocampus (11%), striatum (17%) and frontal cortex (14%) was observed during the observation period. These results show a direct evidence of lipid peroxidation and nitrite formation during seizure activity that could be responsible for the GABAergic and glutamatergic receptor concentration changes during the establishment of SE induced by pilocarpine.

Catalase activity in cerebellum, hippocampus, frontal cortex and striatum after status epilepticus induced by pilocarpine in Wistar rats

The mechanism underlying the vulnerability of the brain to status epilepticus (SE) induced by pilocarpine remains unknown. Oxidative stress has been implicated in a variety of acute and chronic neurologic conditions, including SE. The present study was aimed at was investigating the changes in catalase activity after pilocarpine-induced seizures and SE. The Control group was treated with 0.9% saline (NaCl, subcutaneously (s.c.)) and sacrificed 1h after the treatment. Another group was treated with pilocarpine (400 mg/kg, s.c., Pilocarpine group) and sacrificed 1h after treatment. The catalase activity in the cerebellum, hippocampus, frontal cortex and striatum of Wistar rats was determined. The results have shown that pilocarpine administration and resulting SE produced a significant increase in the catalase activity in the hippocampus (36%), striatum (31%) and frontal cortex (15%) of treated adult rats. Nevertheless, in the adult rat cerebellum after SE induced by pilocarpine no change was observed in the catalase activity. Our results demonstrated a direct evidence of an increase in the activity of the scavenging enzyme (catalase) in different cerebral structures during seizure activity that could be responsible for eliminating oxygen free radicals and might be one of the compensatory mechanisms to avoid the development of oxidative stress during the establishment of SE induced by pilocarpine. Our reports also indicate clear regional differences in the catalase activity caused by pilocarpine-induced seizures and SE and the hippocampus might be the principal area affected and cerebellum does not modify for this parameter studied during epileptic activity.

Antinociceptive activities of the hydroalcoholic extracts from Erythrina velutina and Erythrina mulungu in mice

This work studied the antinociceptive effects of the hydroalcoholic extracts (HAEs) from Erythrina velutina (Ev) and Erythrina mulungu (Em) in three experimental models of nociception in mice. The extract was administered intraperitoneally to female mice at the doses of 200 and 400 mg/kg. Inhibitions of abdominal contractions were observed with the doses of 200 (88.6%; 86.8%) and 400 (95.5%; 83.5%) mg/kg of E. velutina and E. mulungu, respectively, as compared to controls. E. velutina and E. mulungu, at both doses, reduced the nociception produced by formalin in the 1st and 2nd phases and this effect was not reversed by the pretreatment with naloxone. In the hot plate test an increase of the reaction time was observed only at 60 (Ev=18.0+/-2.2; Em=20.8+/-2.52) and 90 min (Ev=20.4+/-1.71; Em=23.7+/-2.32) after the treatment with E. velutina and E. mulungu at the dose of 400 mg/kg as compared to controls (T60=11.1+/-0.74; T90=11.9+/-0.86). This effect was not reversed by naloxone. We conclude that E. velutina and E. mulungu presents antinociceptive effects, which are independent of the opioid system.

Acetylcholinesterase activities in hippocampus, frontal cortex and striatum of Wistar rats after pilocarpine-induced status epilepticus

Experimental manipulations suggest that in vivo administration of cholinergic agonists or inhibitors of acetylcholinesterase (AChE) increases the concentration of acetylcholine. Biochemical studies have proposed a role for AChE in brain mechanisms responsible by development to status epilepticus (SE) induced by pilocarpine. The present study was aimed at investigating the changes in AChE activities in hippocampus, striatum and frontal cortex of adult rats after pilocarpine-induced SE. The control group was treated with 0.9% saline (s.c., control group) and another group received pilocarpine (400 mg/kg, s.c.). Both groups were sacrificed 1 h after treatment. The results have shown that pilocarpine administration and resulting SE produced a significant decrease in the AChE activity in the hippocampus (63%), striatum (35%) and frontal cortex (27%) of adult rats. Our results demonstrated a direct evidence of a decrease in the activity of the AChE in rat brain regions during seizure activity that could be responsible by regulation of acetylcholine levels during the establishment of SE induced by pilocarpine.

Effect of gabaergic, glutamatergic, antipsychotic and antidepressant drugs on pilocarpine-induced seizures and status epilepticus

This work was designed to study the influence of drugs during seizures and status epilepticus (SE) induced by pilocarpine and mortality in adult rats. Fluoxetine (10 and 20 mg/kg), NMDA (N-methyl-D-aspartate, 10 and 20 mg/kg), amitriptyline (25 and 50 mg/kg), ketamine (0.5 and 1.0 mg/kg), gabapentin (100 and 150 mg/kg) and pimozide (10 and 20 mg/kg) were administered intraperitoneally, 30 min prior to pilocarpine (400mg/kg, s.c.). The animals were observed (24h) to determine: number of peripheral cholinergic signs, tremors, stereotyped movements, seizures, SE, latency to first seizure and number of deaths after pilocarpine treatment. Fluoxetine, amitriptyline, NMDA, and pimozide had proconvulsant effects in both doses tested. Smaller and higher doses of these drugs no protected and increased pilocarpine-induced seizures and/or mortality. Gabapentin and ketamine protected against seizures and reduced the latency to first seizure. Thus, these results suggest that caution should be taken in the selection of pharmacotherapy and dosages for patients with epilepsy because of the possibility of potentiating convulsive process toxicity.

Study of Antinociceptive Effect of Isolated Fractions from Petiveria alliacea L. (tipi) in Mice

The acetate (FA), hexanic (FH), hydroalcoholic (FHA) and precipitated hydroalcoholic (FHAppt) fractions from the root of Petiveria alliacea L. were evaluated for antinociceptive effect using the abdominal constriction induced by acetic acid, hot-plate, formalin tests. The open field and rota rod tests were used to evaluate psychomotor function and myorelaxant activity. The fractions were administered intraperitoneally in mice at doses of 100 and 200 mg/kg. Inhibitions of abdominal constrictions were observed with all doses of the fractions, as compared to control. FH and FHAppt, at both doses, reduced the nociception produced by formalin in the 1st (0-5 min) and 2nd (20-25 min) phases, however FHA (100, 200 mg/kg) and FA 200 mg/kg presented significant inhibition on the 1st and 2nd phases, respectively, of this test. A reduction of the locomotor activity was observed in the open field test with all the fractions. These fractions failed to affect the motor coordination in the rota rod test. Results showed that the different fractions of Petiveria alliacea L. have different antinociceptive potentials as demonstrated in the experimental models of nociception in mice, supporting folk medicine use of this plant.

Evaluation of levetiracetam effects on pilocarpine-induced seizures: Cholinergic muscarinic system involvement

Levetiracetam (LEV) is a new antiepileptic drug effective as adjunctive therapy for partial seizures. It displays a unique pharmacological profile against experimental models of seizures, including pilocarpine-induced seizures in rodents. Aiming to clarify if anticonvulsant activity of LEV occurs due to cholinergic alterations, adult male mice received LEV injections before cholinergic agonists' administration. Pretreatment with LEV (30-200 mg/kg, i.p.) increased the latencies of seizures, but decreased status epilepticus and death on the seizure model induced by pilocarpine, 400 mg/kg, s.c. (P400). LEV (LEV200, 200 mg/kg, i.p.) pretreatment also reduced the intensity of tremors induced by oxotremorine (0.5 mg/kg, i.p). [3H]-N-methylscopolamine-binding assays in mice hippocampus showed that LEV200 pretreatment reverts the downregulation on muscarinic acetylcholine receptors (mAChR), induced by P400 administration, bringing back these density values to control ones (0.9% NaCl, i.p.). However, subtype-specific-binding assays revealed that P400- and LEV-alone treatments result in M1 and M2 subtypes decrease, respectively. The agonist-like behavior of LEV on the inhibitory M2 mAChR subtype, observed in this work, could contribute to explain the reduction on oxotremorine-induced tremors and the delay on pilocarpine-induced seizures, by an increase in the attenuation of neuronal activity mediated by the M1 receptors.

Effect of anxiolytic, antidepressant, and antipsychotic drugs on cocaine-induced seizures and mortality

Cocaine abuse may lead to overdose (related to seizures and/or status epilepticus) and to diseases (schizophrenia, depression, and anxiety). This work was designed to study the influence of drugs used to treat psychopathologies associated with cocaine abuse on cocaine-induced seizures and mortality in mice. Fluoxetine (10, 20, 40 mg/kg), imipramine and buspirone (5, 10 mg/kg), pimozide (10, 20 mg/kg), lithium (56.3, 112.5 mg/kg), and naltrexone (25, 50 mg/kg) were administered intraperitoneally, 30 minutes prior to cocaine (90 mg/kg, ip). The animals were observed (30 minutes) to determine: latency to first seizure, number of seizures, and number of deaths after cocaine overdose. Fluoxetine, imipramine, buspirone, and pimozide had pro- or anticonvulsant effects depending on the dose. Smaller doses protected and higher doses increased cocaine-induced seizures and/or mortality. Naltrexone worsened and lithium protected against seizures. Thus, these results suggest that caution should be taken in the selection of pharmacotherapy and dosages for patients with cocaine addiction because of the possibility of potentiating cocaine toxicity.

Monoamine levels after pilocarpine-induced status epilepticus in hippocampus and frontal cortex of Wistar rats

Pilocarpine-induced status epilepticus (SE) is an useful model to study the involvement of neurotransmitter systems as epileptogenesis modulators. Some researches have shown that pharmacological manipulations in dopaminergic, serotonergic, and noradrenergic systems alter the occurrence of pilocarpine-induced SE. The control group was treated with 0.9% saline (control group, s.c.). Another group of rats received pilocarpine (400mg/kg, s.c.) and both groups were sacrificed 24 h after the treatment. This work was performed to determine the alterations in monoamine levels (dopamine (DA), serotonin (5-HT) and norepinephrine (NE)) and their metabolites (3,4-hydroxyphenylacetic acid (DOPAC), homovanilic acid (HVA), and 5-hydroxyindoleacetic acid (5-HIAA)) after pilocarpine-induced SE in hippocampus and frontal cortex of adult rats. The monoamines and their metabolites were determined by reverse-phase high-performance liquid chromatography with electrochemical detection. DA and 5-HIAA concentrations were not altered in the hippocampus of the pilocarpine group, but in the same group the 5-HT (160%), DOPAC (316%) and HVA (21%) levels increased, whereas, the NE (47%) content declined. For the frontal cortex determinations, there was an increase of 20 and 72% in DA and DOPAC levels, respectively, and a decrease in NE (32%), 5-HT (33%) and 5-HIAA (19%) concentrations, but HVA content remained unaltered. These results indicate that pilocarpine-induced SE can alter monoamine levels in different ways depending on the brain area studied, suggesting that different mechanisms are involved.

Effect of one-week ethanol treatment on monoamine levels and dopaminergic receptors in rat striatum

We studied the effects of ethanol on the levels of norepinephrine, dopamine, serotonin (5-HT) and their metabolites as well as on D1- and D2-like receptors in the rat striatum. Ethanol (2 or 4 g/kg, po) was administered daily by gavage to male Wistar rats and on the 7th day, 30 min or 48 h after drug administration, the striatum was dissected for biochemical assays. Monoamine and metabolite concentrations were measured by HPLC and D1- and D2-like receptor densities were determined by binding assays. Scatchard analyses showed decreases of 30 and 43%, respectively, in D1- and D2-like receptor densities and no change in dissociation constants (Kd) 48 h after the withdrawal of the dose of 4 g/kg. Ethanol, 2 g/kg, was effective only on the density of D2-like receptors but not on Kd of either receptor. Thirty minutes after the last ethanol injection (4 g/kg), decreases of D2 receptor density (45%) as well as of Kd values (34%) were detected. However, there was no significant effect on D1-like receptor density and a 46% decrease was observed in Kd. An increase in dopamine and 3,4-dihydroxyphenylacetic acid (DOPAC), a decrease in norepinephrine, and no alteration in 5-HT levels were demonstrated after 48-h withdrawal of 4 g/kg ethanol. Similar effects were observed in dopamine and DOPAC levels 30 min after drug administration. No alteration in norepinephrine concentration and a decrease in 5-HT levels were seen 30 min after ethanol (4 g/kg) administration. Our findings indicate the involvement of the monoaminergic system in the responses to ethanol.

Role of platelet activating factor in the inflammatory and secretory effects of Clostridium difficile toxin A

Clostridium difficile is a major recognized cause of antibiotic-associated diarrhea, an effect mediated through its toxin A. Toxin A has been reported to disrupt epithelial tight junctions, attract neutrophils, and cause striking intestinal inflammation and secretion. Having demonstrated that phospholipase A2 inhibitors block the secretory effects of toxin A, we next wished to examine whether platelet activating factor (PAF) was involved in either the direct epithelial or secretory effects of toxin A. The effects of toxin A on net secretion in ligated rabbit ileal segments were significantly inhibited by the PAF antagonists 10(-4)-10(-5) M BN 52021, 10(-5) M WEB 2170, or 10(-5) M SR 27417 by 59-102%. SR 27417 also inhibited secretion induced by toxin A in loops adjacent to the drug (by 58%). Furthermore, the striking inflammation and epithelial disruption seen at 6 h and ligated ileal segments with toxin A was largely prevented by simultaneous treatment with the PAF antagonist SR 27417. In addition, we noted a significant synergistic effect of 10(-8) M PAF with 10 micrograms/ml toxin A in the ligated rabbit ileal segments. To examine direct effects of PAF antagonists on toxin A in T-84 epithelial cell monolayers, rhodamine-labeled phalloidin stained F-actin demonstrated significant disruption of F-actin by toxin A that was reduced by the PAF antagonist BN 52021 or WEB 2170. However, the PAF antagonists (10(-4) M WEB, 10(-5) M BN or 10(-4) M SR) failed to alter the disruption of T-84 cell tissue resistance by C. difficile toxin A (0.03 micrograms/ml). We conclude that PAF may be involved in the secretory effects of C. difficile toxin A, and that PAF antagonists deserve further study in C. difficile diarrhea.

Pilocarpine-induced status epilepticus: Monoamine level, muscarinic and dopaminergic receptors alterations in striatum of young rats

Behavioural changes, muscarinic and dopaminergic receptors density and levels of monoamines were measured in striatum of rats after pilocarpine-induced status epilepticus (SE). Wistar rats at the age of 21 days were treated with pilocarpine (400mg/kg; subcutaneously) whilst the control group was treated with 0.9% saline (s.c.). Both groups were sacrificed 1h following the treatment. SE induced a muscarinic receptor downregulation of 64% in pilocarpine group. This effect was also observed to be 57% in D(1) and 32% in D(2). In the dissociation constant (K(d)) values in muscarinic and D(1) receptor no alterations were verified. On the other hand, the K(d) value for D(2) was observed to increase 41%. High performance liquid chromatography determinations showed 63, 35, 77 and 64% decreases in dopamine, 3-methoxy-phenylacetic acid, serotonin and 5-hydroxyindoleacetic acid contents, respectively. The homovanilic acid level was verified to increase 119%. The noradrenaline content was unaltered. A direct evidence of monoamine levels alterations can be verified during seizure activity and receptor density changes appear to occur in an accentuated way in immature brain during the estabilishment of SE induced by pilocarpine.

Effects of chronic ethanol treatment on monoamine levels in rat hippocampus and striatum

We studied the effects of ethanol on concentrations of noradrenaline (NE), dopamine (DA) and serotonin (5-HT) and their metabolites in rat hippocampus and striatum. Ethanol (2 or 4 g/kg, po, from a 20% aqueous solution) was administered daily to male Wistar rats (4-13 per group) for 30 days and animals were sacrificed 30 min or 48 h after the last administration. Monoamines were measured by HPLC and considered significant at P < 0.05. A 47% increase in 5-HT levels was observed in the hippocampus with 4 g/kg ethanol in the 30-min protocol. Ethanol (2 and 4 g/kg) decreased DA (2114.5 +/- 126.4 and 1785.1 +/- 234.2 ng/g wet tissue, respectively) and 3,4-dihydroxyphenylacetic acid (DOPAC, 1477.6 +/- 132.1 and 1218.8 +/- 271.7 ng/g wet tissue, respectively) levels, while the higher dose also decreased NE (159.8 +/- 13.5), 5-HT (228.0 +/- 46.8) and 5-hydroxy-3-indoleacetic acid (5-HIAA, 304.4 +/- 37.2 ng/g wet tissue), in the striatum after a 48-h withdrawal as compared to controls (DA: 3063.9 +/- 321.3; DOPAC: 2379.6 +/- 256.0; NE: 292.8 +/- 50.2; 5-HT: 412.4 +/- 36.2; 5-HIAA: 703.9 +/- 61.4 ng/g wet tissue). In the 30-min protocol, ethanol (2 or 4 g/kg) decreased striatal NE (66 and 70%) and DA (50 and 36%) levels. On the other hand, increases were seen in 5-HIAA (146 and 153%) and 5-HT (59 and 86%) levels. Ethanol (2 g/kg, po) increased the homovanillic acid (HVA)/DA ratio (129%) in the striatum in the 30-min protocol, while at the higher dose it increased the HVA/DA ratio in the 48-h protocol (61%). These results indicate alterations in monoamines, mainly in the striatum, after chronic ethanol, which are influenced by dose and by the length of time after the last drug administration.

Study pharmacologic of the GABAergic and glutamatergic drugs on seizures and status epilepticus induced by pilocarpine in adult Wistar rats

This work was designed to study the influence of drugs during seizures and status epilepticus (SE) induced by pilocarpine and mortality in adult rats. Glutamate (10 and 20 mg/kg), N-methyl-d-aspartate (NMDA, 5 and 10 mg/kg), ketamine (1.5 and 2.0 mg/kg), gabapentin (200 and 250 mg/kg), phenobarbital (50 and 100 mg/kg) and vigabatrin (250 and 500 mg/kg) were administered intraperitoneally, 30 min prior to pilocarpine (400 mg/kg, i.p.). The animals were observed (24 h) to determine: number of peripheral cholinergic signs, tremors, stereotyped movements, seizures, SE, latency to first seizure and number of deaths after pilocarpine treatment. NMDA and glutamate had pro-convulsive effects in both doses tested. Smaller and higher doses of these drugs no protected and increased pilocarpine-induced seizures and/or mortality. Gabapentin, vigabatrin, phenobarbital and ketamine protected against seizures and increased the latency to first seizure. Thus, these results suggest that caution should be taken in the selection of pharmacotherapy and dosages for patients with seizures and SE because of the possibility of facility the convulsive process toxicity, SE and the mortality of adult animals in this seizures model that is similar temporal lobo epilepsy in humans.

[The cost of liver transplantation at a university hospital of Brazil]

OBJECTIVE

To investigate if liver transplants were cost effective at a University Hospital of Ceará.

METHODS

We evaluated data from the medical records of 62 liver transplant patients performed in 2007, from the day of admission for the transplant to the date of discharge or death. Indicators such as length of hospital stay and location ,quantity of medical material and medication used, as well as the investigations and procedures performed were determined.

RESULTS

The population was mostly male from the Northeast of Brazil with an mean age of 45 years. The mean total cost of a liver transplant was US$20,605.01. The largest part was payment for the professional team involved in the liver removal and transplant, followed by hospital stay , medication used during surgery and hospitalization, and products (medication and materials) used in the liver removal. According to the current schedule, the SUS made the following payments to HUWC; US$1,322.97 for liver removal, US$3,223.56 for medical fees and US$32,235.68 for the package including the complete surgical procedure, hospital expenses and care up to the seventh day of hospitalization.

CONCLUSION

Results were similar to those found by other Brazilian transplant centers. Liver transplantation in Ceará is an economically viable procedure based upon the financial transfer from SUS.

Anxiolytic-like effects of standardized extract of Justicia pectoralis (SEJP) in mice: Involvement of GABA/benzodiazepine in receptor

Justicia pectoralis (Acanthaceae) is used as an antiinflammatory, antimicrobial and bronchodilator, and its extract exerts an anxiolytic-like effect profile in animal models. This work presents the behavioral effects of an aqueous standardized extract of Justicia pectoralis (SEJP) in animal models, such as the elevated plus maze (EPM), light/dark, open field, rota rod and pentobarbital sleep time. The extract was administered intragastrically to male mice at single doses of 50, 100 and 200 mg/kg, while diazepam 1 or 2 mg/kg was used as a standard drug and flumazenil 2.5 mg/kg was used to evaluate the participation of benzodiazepinic receptors. The results showed that, similar to diazepam (1 mg/kg), SEJP significantly modified all the observed parameters in the EPM test, without altering the general motor activity in the open field, rota rod and pentobarbital sleep time tests. Flumazenil reversed not only the diazepam effect but also the SEJP effect. In the same way, all doses of SEJP increased the time of permanence in the light box in the light/dark test. The results showed that SEJP presented an anxiolytic-like effect, disproving sedative effects.

Prolidase contamination in commercial bovine serum albumin

Bovine serum albumin from a number of commercial sources were screened for the presence or absence of peptidase contamination. Peptidase activity was monitored using various peptides as substrates. Two commercial preparations were found to have peptidase activity, and the enzyme was identified, on the basis of its substrate specificity, as prolidase (EC 3.4.14.9). The contaminating activity was in the order of 3-4 units/g albumin.

Pharmacological studies of the opioids, mood stabilizer and dopaminergic drugs on pilocarpine-induced seizures and status epilepticus

This work was designed to study the influence of drugs during seizures and status epilepticus (SE) induced by pilocarpine and mortality in adult rats. Morphine (0.1 and 0.2 mg/kg), SCH 23390 (0.1 and 0.2 mg/kg), haloperidol (5 and 10mg/kg) and lithium (30 and 60 mg/kg) were administered intraperitoneally (i.p.), 30 min before to pilocarpine (400 mg/kg, s.c.). The animals were observed (24 h) to determine: number of peripheral cholinergic signs, tremors, stereotyped movements, seizures, SE, latency to first seizure and number of deaths after pilocarpine treatment. Morphine and haloperidol had proconvulsant effects in both doses tested. Smaller and higher doses of these drugs no protected and increased pilocarpine-induced seizures, SE and/or mortality. SCH 23390 protected against seizures, increased the latency to first seizure and reduced the mortality of the animals treated with pilocarpine Theses results suggest that dopamine receptor system receptor subtypes exert opposite functions on the regulation of convulsive activity. The morphine is proconvulsant in lower doses. The opioids in high doses tested exert an action proconvulsant during the establishment of epileptic activity induce by pilocarpine. The lithium no protected the animals against seizures induced by pilocarpine and is used which a model of epilepsy associated with lower doses of pilocarpine in several studies, suggesting absence of the effect anticonvulsants in rodents.

Determination of amino acid levels in the rat striatum, after administration of ethanol alone and associated with ketamine, a glutamatergic antagonist

The main goal of this study was to determine the amino acids (glutamate, aspartate, glutamine and tyrosine) levels in the rat striatum, after ethanol administration alone and/or associated with ketamine. In protocol 1 (Et+ketamine-1), ethanol was administered to male Wistar rats until the 7th day, and at the next day the group received only ketamine (25mg/kg, i.p.) up to the 14th day. In protocol 2 (Et+ketamine-2), ethanol was also administered up to the 7th day, and was associated with ketamine from the 8th up to the 14th day. In other groups, animals were treated daily with ethanol (4 g/kg, p.o.), for 7 or 14 days or ketamine daily for 7 days. Controls were administered with distilled water for 7 days. Results showed that, in protocol 1, aspartate (ASP) levels increased after ketamine administration, as compared to the controls. This effect was inhibited in the group Et+ketamine-1. Ethanol (7 days) increased glutamate (GLU) levels, as compared to control, and this effect did not differ significantly from that observed in the ketamine group. When ketamine was administered after the ethanol withdrawal (protocol 1), no alterations in those amino acid concentrations were seen, as compared to the control and ketamine groups. A tendency for increasing GLU levels was observed, after administration of ethanol (14 days) or ketamine alone or associated (protocol 2), when compared to control values. In protocol 2, TYR levels decreased as related to controls and to the 14-day ethanol-treated group. We can assume that ketamine presents only an antagonist effect, in animals pretreated with ethanol, followed by ketamine administered from the 8th day on. This is due to the fact that NMDA receptors are already sensitized, leading to a decrease in these receptors functions and consequently to ASP and GLU releases.

Involvement of monoaminergic targets in the antidepressant- and anxiolytic-like effects of the synthetic alkamide riparin IV: Elucidation of further mechanisms through pharmacological, neurochemistry and computational approaches

Despite recent advances, current antidepressants have considerable limitations: late onset of action and the high profile of refractoriness. Biomedical research with natural products has gained growing interest in the last years, and had provide useful candidates for new antidepressants. Riparins are a group of natural alkamides obtained from Aniba riparia, which had marked neuroactive effects, mainly as antidepressant and antinociceptive agents. We made modifications of the basic structure of riparins, originating a synthetic alkamide, also known as riparin IV (RipIV). RipIV demonstrated a superior analgesic effect than its congeners and a marked antidepressant-like effect. However, the basic mechanism for the central effects of RipIV remains unknown. Here, we aimed to investigate the participation of monoaminergic neurotransmission targets in the antidepressant-like effects of RipIV. To do this, we applied a combined approach of experimental (classical pharmacology and neurochemistry) and computer-aided techniques. Our results demonstrated that RipIV presented antidepressant- and anxiolytic-like effects without modifying locomotion and motor coordination of mice. Also, RipIV increased brain monoamines and their metabolite levels. At the higher dose (100 mg/kg), RipIV increased serotonin concentrations in all studied brain areas, while at the lower one (50 mg/kg), it increased mainly dopamine and noradrenaline levels. When tested with selective receptor antagonists, RipIV antidepressant effect showed dependence of the activation of multiple targets, including D1 and D2 dopamine receptors, 5-HT2A/2, 5-HT3 receptors and α2 adrenergic receptors. Molecular docking demonstrated favorable binding conformation and affinity of RipIV to monoamine oxidase B (MAO-B), serotonin transporter (SERT), α1 receptor, D2 receptor, dopamine transporter (DAT) and at some extent GABA-A receptor. RipIV also presented a computationally predicted favorable pharmacokinetic profile. Therefore, this study demonstrated the involvement of monoaminergic targets in the mechanism of RipIV antidepressant-like action, and provide evidence of it as a promising new antidepressant.

Differential effects of cocaine-induced seizures and lethality on M(1)-like muscarinic and dopaminergic D (1)- and D (2)-like binding receptors in mice brain

This work was designed to study the changes produced by cocaine-induced seizures and lethality on dopaminergic D(1)- and D(2)-like receptors, muscarinic M(1)-like binding sites, as well as acetylcholinesterase activity in mice prefrontal cortex (PFC) and striatum (ST). Binding assays were performed in brain homogenates from the PFC and ST and ligands used were [(3)H]-N-methylscopolamine, [(3)H]-NMS (in the presence of carbachol), [(3)H]-SCH 23390 and [(3)H]-spiroperidol (in presence of mianserin), for muscarinic (M(1)-like), D(1)- and D(2)-like receptors, respectively. Brain acetylcholinesterase (AChE) activity was also determined in these brain areas. Cocaine-induced SE decreased [(3)H]-SCH 23390 binding in both ST and PFC areas. A decrease in [(3)H]-NMS binding and an increase in [(3)H]-spiroperidol binding in PFC was also observed. Cocaine-induced lethality increased [(3)H]-spiroperidol binding in both areas and decreased [(3)H]-NMS binding only in PFC, while no difference was seen in [(3)H]-SCH 23390 binding. Neither SE, nor lethality altered [(3)H]-NMS binding in ST. AChE activity increased after SE in ST while after death the increase occurred in both PFC and ST. In conclusion, cocaine-induced SE and lethality produces differential changes in brain cholinergic and dopaminergic receptors, depending on the brain area studied suggesting an extensive and complex involvement of these with cocaine toxicity in central nervous system.

[Attention deficit hyperactivity disorder (ADHD) in children: neurobiological aspects, diagnosis and therapeutic approach]

INTRODUCTION

The attention deficit hyperactivity disorder (ADHD) is usually associated to child development, presenting a strong neurobiological influence and being, thus, mostly common in childhood. This disorder is characterized by a persistent pattern of lack of attention and/or by hyperactivity and impulsivity.

OBJECTIVE

To conduct a systematic literature review on ADHD in children, focusing neurobiological aspects, diagnosis and therapeutic approaches.

METHODOLOGY

This is a literature review about ADHD in childhood, from 1994 through 2008. The neurobiological mechanisms that participate in ADHD are complex, involving the dopaminergic, noradrenergic and serotonergic systems. The diagnosis of ADHD must be based on the clinical behavior, since there is no biological marker defined. Metilfenidate is the main drug used for children's treatment.

CONCLUSION

The search for relief of ADHD symptoms ought to be based on organic treatments, other specific treatments using medications or neurofeedbacks, as well as behavior therapies.