Differential behavioral outcomes of 3,4-methylenedioxymethamphetamine (MDMA-ecstasy) in anxiety-like responses in mice

Anxiolytic and anxiogenic-like behavioral outcomes have been reported for methylenedioxymethamphetamine (MDMA or ecstasy) in rodents. In the present experiment, we attempted to identify behavioral, hormonal and neurochemical outcomes of MDMA treatment to clarify its effects on anxiety-related responses in 2-month-old Balb/c male mice (25-35 g; N = 7-10 mice/group). The behavioral tests used were open field, elevated plus maze, hole board, and defensive behavior against predator odor. Moreover, we also determined striatal dopamine and dopamine turnover, and serum corticosterone levels. MDMA was injected ip at 0.2, 1.0, 5.0, 8.0, 10, or 20 mg/kg. MDMA at 10 mg/kg induced the following significant (P < 0.05) effects: a) a dose-dependent increase in the distance traveled and in the time spent moving in the open field; b) decreased exploratory activity in the hole board as measured by number of head dips and time spent in head dipping; c) increased number of open arm entries and increased time spent in open arm exploration in the elevated plus maze; d) increased time spent away from an aversive stimulus and decreased number of risk assessments in an aversive odor chamber; e) increased serum corticosterone levels, and f) increased striatal dopamine level and turnover. Taken together, these data suggest an anxiogenic-like effect of acute MDMA treatment, despite the fact that behavioral anxiety expression was impaired in some of the behavioral tests used as a consequence of the motor stimulating effects of MDMA.

Neurotransmitter evaluation in the hippocampus of rats after intracerebral injection of TsTX scorpion toxin

TsTX is an á-type sodium channel toxin that stimulates the discharge of neurotransmitters from neurons. In the present study we investigated which neurotransmitters are released in the hippocampus after TsTX injection and if they are responsible for electrographic or histopathological effects. Microdialysis revealed that the toxin increased glutamate extracellular levels in the hippocampus; however, levels of gamma-aminobutyric acid (GABA), glycine, 5-hydroxyindoleacetic acid (5-HIAA), homovanillic acid (HVA) and 3,4-dihydroxyphenylacetic acid (DOPAC) were not significantly altered. Neurodegeneration in pyramidal cells of hippocampus and electroencephalographic alterations caused by the toxin were blocked by pretreatment with riluzole, a glutamate release inhibitor. The present results suggest a specific activity of TsTX in the hippocampus which affects only glutamate release.

Cromatografia em camada delgada para o diagnóstico da intoxicação por aldicarb ("chumbinho") em cães e gatos / Thin-layer chromatography for aldicarb poisoning diagnosis in dogs and cats

Avaliou-se a cromatografia em camada delgada (CCD) como método de diagnóstico toxicológico para os casos de intoxicação por aldicarb em cães e gatos, utilizando-se 50 amostras de conteúdo gástrico obtidas durante a necropsia e 50 amostras de alimentos utilizados como iscas para intoxicar criminalmente os animais. Todas as amostras resultaram positivas para o aldicarb, mostrando ser a CCD uma técnica qualitativa eficiente, rápida e de baixo custo, com uso potencial na toxicologia veterinária forense

The present study concerns about the identification of aldicarb residues using thin-layer chromatography (TLC) in 50 samples of gastric content obtained from the necropsy of dogs and cats and 50 samples of foods suspected of being used as baits. All samples resulted positive for aldicarb showing that the TLC is an efficient, fast and not expensive qualitative method for the detection of aldicarb, being useful for this purpose in the forensic veterinary toxicology

Developmental and behavioral effects of postnatal amitraz exposure in rats

The effects of postnatal amitraz exposure on physical and behavioral parameters were studied in Wistar rats, whose lactating dams received the pesticide (10 mg/kg) orally on days 1,4,7,10,13,16 and 19 of lactation; control dams received distilled water (1 ml/kg) on the same days. A total of 18 different litters (9 of them control and 9 experimental) born after a 21-day gestation were used. The results showed that the median effective time (ET50) for fur development, eye opening, testis descent an onset of the startle response were increased in rats postnatally exposed to amitraz (2.7, 15.1, 21.6 and 15.3 days, respectively) compared to those of the control pups (1.8, 14.0, 19.9 and 12.9 days, respectively). The ages of incisor eruption, total unfolding of the external ears, vaginal and ear opening and the time taken to perform the grasping hindlimb reflex were not affected by amitraz exposure. Pups from damps treated with amitraz during lactation took more time (in seconds) to perform the surface righting reflex on postnatal days (PND) 3 (25.0 + 2.0), 4 (12.3 + 1.2) and 5 (8.7 + 0.9) in relation to controls (10.6 + 1.2;4.5 + 0.6 and 3.4 + 0.4, respectively); the climbing response was not changed by amitraz. Postnatal amitraz exposure increased spontaneous motor activity of male and female pups in the open-field on PND 16 (140 + 11) and 17 (124 + 12), and 16 (104 + 9), 17 (137 + 9) and 18 (106 + 8), respectively. Data on spontaneous motor activity of the control male and female pups were 59 + 11 and 69 + 10 for days 16 and 17 and 49 + 9, 48 + 7 and 56 + 7 for days 16,17 and 18, respectively. Some qualitative difference were also observed in spontaneous motor behavior; thus, raising the head, shoulder and pelvis matured one or two days later in the amitraz-treated offspring. Postnatal amitraz exposure did not change locomotion and rearing frequencies or immobility time in the open-field on PND 30,60 and 90. The present findings indicate that postnatal exposure to amitraz caused transient development and behavioral changes in the exposed offspring and suggest that further investigation of the potential health risk of amitraz exposure to developing human and animal offsprings may be warranted.

Effects of amitraz on the arterial blood pressure and body rectal temperature of conscious rats

O presente trabalho estuda os efeitos da administraçäo única de amitraz (100 mg/kg) sobre a pressäo sanguínea arterial e a temperatura corporal de ratos Wistar. A administraçäo de amitraz diminuiu a pressäo sanguínea arterial e também produziu hipotermia. A administraçäo de tiramina (100,0 mg/kg) induziu um aumento significativo (p<0,05) na pressäo sanguínea arterial de ratos que receberam previamente amitraz, näo alterando a dos ratos controle. Metade dos ratos que receberam amitraz e tiramina morreram entre 3 e 10 horas após a administraçäo, fato este näo ocorrido com os animais que receberam soluçäo fisiológica e posteriormente tiramina. Os sinais de intoxicaçäo dos animais experimentais incluíram sedaçäo, falta de coordenaçäo motora e coma. A posterior administraçäo de ioimbina (10,0 mg/kg) näo alterou a hipotermia produzida pela administraçäo de amitraz (p<0,05). Apesar de näo poder ser excluída uma possível açäo do amitraz sobre alfa2-noradrenoceptores cerebrais, os resultados indicam uma provável açäo deste praguicida inibindo a enzima monoaminoxidase

Effects of amitraz on isolation-induced aggression in mice

Estudaram-se os efeitos do amitraz, um derivado farmacomidínico, no comportamento agressivo induzido pelo isolamento social em camundongos. Os resultados mostraram que o Amitraz aumentou a latência para o primeiro ataque e diminuiu näo somente a duraçäo de briga como as frequências de ataques entre esses animais. Estes resultados sugeriram que os efeitos do praguicida sobre o comportamento agressivo dos camundongos foram consequência de um efeito inibitório do mesmo sobre a atividade da enzima monoamina oxidase no Sistema Nervoso Central, e, consequentemente, de um aumento dos níveis cerebrais de serotonina

Some behavioral effects of the pesticide amitraz

Acute oral administration of the pesticide amitraz at the doses of 60 and 100 mg/kg (N = 10 per group) significantly decreased the rearing frequency of rats observed in a open field to 8 + or - 8 and 5 + or- 5, respectively, when compared to 28 + or - 5 for control rats treated with vehicle only. The same doses of amitraz (N = 10 per group) increased duration of immobility to 80 + or - 50 and 113 + or - 64 s, respectively, when compared to 113 + or - 64 s for the controls. Acute oral administration of amitraz (20, 60 or 100 mg/kg, N = 10 per group) significantly increased the convulsive threshold dose of rats for strychnine, picrotoxin and pentylenetetrazole. A mitraz administered ip to mice at the doses of 20, 60 and 100 mg/kg (N = 10 per group) significantly increased sleeping time in a dose-dependent manner to 96 + or - 26, 120 + or - 29 and 198 + or - 58 min, respectively, when compared to 45 + or - 15 min for control mice treated with vehicle only. These results indicate that amitraz produces a depressant effect on the central nervous system