Biomedical subjects
Publications and source records attributed to M M Bernardi.
The effects of essential oil of Croton zehntneri (Euphorbiaceae), orally administered were studied on behavioral parameters using rats and mice. The oil suspension did not modify pentobarbital induced-hypnosis, stereotypic behavior, catalepsy and amphetamine-induced hypermotility. The open-field behaviors were decreased and the minimal convulsant dose of pentylenetetrazole was increased.
Female Wistar rats were exposed to a subconvulsant dose of picrotoxin (0.75 mg/kg, sc) on day 18 of pregnancy, immediately after parturition and daily during the first 5 days of lactation. In adulthood, the offspring were tested in an open-field, in an elevated plus maze and for social interaction. Results showed increased locomotor activity (75 days of age) and decreased social interaction (90 days of age) in experimental male rats compared to control male rats. No effects on behaviors related to anxiety were observed in males or females tested in the plus maze apparatus. An additional comparison of the activity of male and female animals perinatally treated with picrotoxin showed a lack of the classical sexual dimorphic responses in the open-field (control male = 68.7 +/- 6.31; control female = 98.4 +/- 6.31; experimental male = 89.6 +/- 6.32; experimental female = 113.2 +/- 4.74). We suggest that perinatal picrotoxin exposure may interfere with normal male masculinization rather than increasing anxiety in male rats.
Catnip or catmint (Nepeta cataria) is a plant used extensively to treat human diseases and in toys for pets. We investigated the effects of acute and long-term administration of the plant on some behaviors of mice. The plant was fed as 10% of the normal diet for 2 h/d for 1 or 7 d. Acute and long-term dosing increased both rearing and locomotion frequencies observed in an open field. Acute exposure to catnip increased stereotyped behavior and susceptibility to seizures, did not interfere with haloperidol-induced catalepsy, and decreased sleeping time after sodium pentobarbital administration. Long-term exposure induced tolerance to stereotypic behavior, catalepsy and sleeping time, and increased the susceptibility to seizures induced by picrotoxin and strychnine. An amphetamine-like effect of catnip was suggested to explain the acute effects, while dispositional and functional adaptative changes were considered involved with the long-term effects.
Pretreatment of mice with 30 mg xylazine/kg ip protected against convulsions induced by amphetamine, but it intensified pentylenetetrazole- and strychnine-induced seizures. Xylazine pretreatment also protected rats against electroshock-induced convulsions. These findings support a noradrenergic mechanism being involved in the proconvulsant and/or anticonvulsant effects of xylazine.
Our present work investigated the effect of fenvalerate, a pyrethroid type II pesticide, on conditioned behaviors of rats. Pre-training administration of the pesticide did not modify passive avoidance but decreased active avoidance responses and operant conditioned responses; pre-training or pre-test administration of fenvalerate induced a facilitatory effect on passive avoidance task; pre-training and/or pre-test treatments reduced active avoidance responses of rats which received the pesticide before test; and post-training treatments were not capable of modifying both active and passive avoidance responses. Increased emotionality produced by the action of fenvalerate on the sympatho-adrenal system could be responsible for the differences observed between active and passive avoidance responses.
Hemorrhagic events remain the most worrisome complication in patients receiving drugs that alter hemostasis for treatment of acute coronary syndromes. The 7E3 Fab monoclonal antibody provides a dose-dependent inhibition of platelet aggregation via the glycoprotein IIb/IIIa receptor. This study examines the correlation of hemostatic parameters with bleeding events in patients receiving intravenous 7E3 while enrolled in acute myocardial infarction and high-risk percutaneous transluminal coronary angioplasty pilot studies. Patients with acute myocardial infarction received 100 mg of tissue-type plasminogen activator over 3 hours followed by an escalating intravenous bolus dose of murine 7E3 (0.1 mg/kg [n = 5], 0.2 mg/kg [n = 22], 0.15 mg/kg [n = 13], 0.25 mg/kg [n = 20]). Patients in the high-risk angioplasty trial received a chimeric 7E3 bolus (up to 0.25 mg/kg) with (n = 32) or without (n = 15) intravenous continuous infusion of 7E3 (10 micrograms/min for 6 to 24 hours) after elective angioplasty. Patients in both studies received aspirin therapy (325 mg/day) and partial thromboplastin time-guided (1.5 to 2 times normal) heparin infusion. Bleeding events occurred in 34 of 124 patients (27%). The median template bleeding times (minutes) for patients in the groups with bleeding versus no bleeding events in the trials was 13.5 versus 14 and 30 versus 30, respectively (p = NS). In patients with myocardial infarction, a substantial decline in platelet count at 24 hours was associated with bleeding (p = 0.02).(ABSTRACT TRUNCATED AT 250 WORDS)
Crude venom obtained from Crotalus durissus terrificus (Cdt) was tested for its possible analgesic effect in mice. Subcutaneous (s.c.), intraperitoneal (i.p.) or oral (p.o.) administration of the venom caused an antinociceptive effect in mice as measured by the acetic acid-induced writhing method and the hot plate test. The antinociceptive activity was dose and time dependent and persisted after neutralization of the venom with a specific antivenin. It was demonstrated that the factor(s) has an apparent mol. wt of less than 3000 and that its antinociceptive effect is abolished by trypsin treatment. The demonstration that morphine enhances the analgesic effect of Cdt venom and naloxone antagonizes this effect suggests an endorphin-like activity for the factor(s) herein described.
The effect of ovarian steroids on sedative effects of diphenhydramine (D), a histamine H1 receptor blocker, was determined. Seventy-five female Wistar rats were randomly divided into three groups: Group 1 (N = 54) was ovariectomized, group 2 (N = 7) was sham-operated, and group 3 (N = 14) was intact. The ovariectomized rats were then subdivided into 4 groups. Two groups received peanut oil 54 and 6 h before treatment with saline solution (group OS) or 20 mg/kg D (group OD). The other two groups received 50 micrograms/kg 17-beta-estradiol and 2 mg/kg progesterone, respectively, 54 and 6h before treatment with saline solution (group OHS) or 20 mg/kg D (group OHD). The sham-operated animals were treated as the OS group. Intact animals were injected with saline (group IS) or 20 mg/kg D (group ID) on the day of estrus, as determined by vaginal smears taken in the morning before the behavioral observations. Rats were observed for 6 min in the open field during the dark period of the cycle, 15 min after the administration of saline or D. There was a similar decrease in locomotion and rearing frequencies in OHS vs OHD and IS vs ID groups. Nevertheless, a lack of D sedative effect was observed in OD rats (locomotion and rearing frequencies, 56.0 +/- 3.3 vs 46.1 +/- 3.8 and 15.5 +/- 1.6 vs 15.2 +/- 1.6., for OS and OD groups, respectively). The results suggest that the sedative effect of diphenhydramine depends on the presence of ovarian steroids.
The aim of the present study was to evaluate the impact of prenatal exposure to low doses of aldrin on physical and behavioral developments of rats (1-21 days old). To detect the possible persistent adversities produced by this exposure, the animals were also tested when adults (90 days old). Plasma determinations of both aldrin and its metabolite dieldrin and histopathological evaluations of brain slices were also performed in adult animals. Pregnant female rats were subcutaneously (s.c.) treated with aldrin (1.0 mg/kg) or with its vehicle (0.9% NaCl solution plus Tween-80) from day 1 of pregnancy until delivery. Results show that prenatal aldrin administration was able to decrease the median effective time (TE50) for incisor teeth eruption and to increase the TE50 for testes descent; other parameters indicative of physical development were not modified. Aldrin and dieldrin were not found in plasma of the adult rats; no differences were observed between control and experimental rats in the cellular and structural organization of the cerebral cortex neurones. Prenatal aldrin administration produced no impairment of adult animal's behavior in an avoidance learning test; nevertheless, the locomotor frequency of the experimental rats was higher than that of controls at 21 and 90 days old. When adults, these experimental rats had their performance in a hole-board apparatus (total number and duration of head-dips) also higher than that of the control ones. It was concluded that prenatal aldrin exposure induced not only developmental changes in the rat pups but also persistent behavioral alterations in adulthood, when the pesticide was not present in these animals.
Bracken fern (Pteridium aquilinum L Kuhn), is widely food in many parts of the world; the toxic effects have been demonstrated on many species of animals, and both carcinogenicity and enzootic hematuria has been studied. We investigated the effects of feeding bracken fern on the development of female rats and their offspring. The plant was fed as 30% of the normal diet on an ad libitum basis. Bracken fern did not modify the weight gain of the female rats during development, nor affect estrus cycle duration or milk production, the plant did reduce female fertility and weight gain during pregnancy. It also adversely affected physical and neurobehavioral development in the offspring.
Female pregnant rats were treated with 20.0 mg/kg diphenhydramine (DPH) or the same volume of saline solution (NaCl 0.9%), SC, daily during pregnancy. As adults, male pups were tested for stereotyped behavior in response to apomorphine (1 mg/kg, SC) administration. No differences between DPH-exposed and control rats were evident. In another group of rats, dopamine (DA) and homovanillic acid (HVA) levels were quantified in striatal samples. DA levels were equivalent, but increased levels of HVA were observed. Based upon these data we suggest that prenatal exposure to DPH, a histamine (H1) receptor antagonist, reduces presynaptic dopaminergic mechanisms without altering postsynaptic dopaminergic function in adulthood.
1. In order to evaluate the relative contribution of fostering procedures in the analysis of the development of rats prenatally exposed to diphenhydramine (20 mg/kg/day, sc) the weight gain of litters fostered or not by their biological mothers were examined from 2-21 days of age. 2. Maternal behavior and milk production were also assessed. 3. The results showed a decreased weight gain only in offspring fostered by mothers from different prenatal treatments and a lack of effects on maternal behavior and milk production. 4. It was concluded that the reduced weight of cross-fostered litters was mediated through an interference with postnatal mother-offspring interaction, which was not herein identified.
The effects of aqueous Croton zehntneri leaf and branch extracts, orally administered, on some dopaminergic- and cholinergic-related behaviours were studied in rats and mice. The leaf extract did not modify apomorphine-induced stereotypic behavior, haloperidol-induced catalepsy and active avoidance/escape responses. The branch extract reduced stereotypy but did not interfere with catalepsy and active avoidance behavior. Both extracts were capable of increasing the tremor induced by oxotremorine.
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The prenatal effects of exposure to the insecticide cyhalothrin on the sexual maturation and sexual behavior of rats were investigated. Female rats were dermally treated with 1 ml/day of 0.02% (w/v) aqueous cyhalothrin solution or its vehicle throughout pregnancy. This insecticide administration delayed the age of testicle descent but did not modify the age of vaginal opening. In adulthood, both male and female rat sexual behaviors were not different from vehicle-treated animals. It was concluded that prenatal exposure to cyhalothrin can induce alterations in the development of certain physical characteristics of rats which are not correlated with functional deficiencies in the animals' later life.
We investigated the prenatal effects of cyhalothrin exposure on the physical and behavioral development of infant and adult rats. Female rats were treated by dermal exposure with a 0.018% cyhalothrin aqueous solution (1 ml/d) or the cyhalothrin vehicle during their entire pregnancy. The pesticide delayed development of fur, the ear and eye openings and descent of the testes in the offspring. The exploratory behavior of the rats prenatally exposed to cyhalothrin decreased. No differences were observed between control and experimental animals in inhibitory avoidance tasks at 90 d of age in open field activity. Alterations in physical parameters and possible effects of the pesticide on epidermal growth factor and hormonal levels were considered. Since no overt of signs of maternal or neonatal toxicity were observed, the decrease in adult motivational behavior was attributed to a specific effect of the pesticide administered during the prenatal period. We concluded that prenatal cyhalothrin exposure induced subtle and persistent changes in the physical development and behavior of rats.
Cyhalothrin, a pyrethroid insecticide, was administered to female Wistar rats as a 0.02% solution plus 0.04% sucrose (w/v) in drinking water from whelping to pup weaning after 21 days of lactation. The pesticide did not change the maternal behavior of the dams as measured by the scoring system of Soderstein and Eneroth. The body weight of pups exposed to the pesticide and at age 90 days was not different from that of controls, and the motor activity of the pups measured in a simple photocell activity cage was not affected by pesticide treatment. Furthermore, no overt signs of neural toxicity were observed in the offspring. However, the treatment disrupted rat behavior in adulthood when assessed by using an inhibitory avoidance learning task. Thus, inhibitory avoidance tests carried out on rats at 90 days of age were capable of demonstrating neural toxicity of Cyhalothrin (0.02%) present only in the drinking water of dams during 21 days of lactation.
In order to study the involvement of the brain histamine system on the sexual behavior of rats prenatally exposed to the histamine H1 receptor blockader, diphenhydramine (DPD), the female lordotic response and male sexual behavior were analyzed. The results show that the lordotic response in the prenatal DPD-treated rats was increased in relation to control animals. Impairment of male sexual behavior was indicated by an increase in ejaculation latency, in the number of mounts and a decrease in the number of ejaculations up to 30 min after the first intromission. Prenatal exposure to DPD thus appears to alter female and male sexual behavior on reaching adulthood.