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Biomedical subjects

J Palermo-Neto

Publications and source records attributed to J Palermo-Neto.

At least 73 records · Page 4Linked to original sources
PubMed1989

Behavioral aspects of GABAergic-dopaminergic interactions in the central nervous system.

GABAergic-dopaminergic relationships in rats were analysed quantitatively by means of behavioral studies. Acute and long-term haloperidol administration induced significant leftward displacement of the control dose-response curves for picrotoxin but not those for strychnine or 3-mercaptopropionic acid (3-MPA). Apomorphine given acutely increased the sensitivity of the animal to strychnine but not to picrotoxin or 3-MPA. In animals that presented convulsion a stereotyped gnawing and/or licking behavior was observed immediately after the ictus activity as a consequence of the combined acute administration of haloperidol and picrotoxin. Long-term haloperidol treatment increased the gnawing and/or licking behavior immediately before and/or after the ictus activity induced by picrotoxin (1 and 72 h after haloperidol withdrawal) or 3-MPA (72 h after withdrawal). A possible effect of the drugs employed on the DA-nigroamygdaloid and/or the GABA-striatonigral fiber systems is discussed.

3-Mercaptopropionic Acid↗
PubMed1989

Perinatal bromopride treatment: effects on motor activity and stereotyped behavior of offspring.

Effects of different perinatal treatments with bromopride (BRO), a dopaminergic blocking agent, on open-field behavior and apomorphine (APO)-induced stereotypy were examined just after weaning and in adult Wistar rats. Weanling rats of mothers treated with BRO during lactation had greater general activity (24-48 hours after weaning) and higher stereotypy scores (96 hours after weaning) than pups from vehicle-treated control mothers. These results were not observed in rats of mothers treated with BRO only during pregnancy (BV group), nor was it as evident in animals of mothers treated during pregnancy and lactation (BB group). When adults, females had normal estrous cycles and the characteristic higher ambulation than males. However, males from groups BV and BB had lower ambulation frequencies than control males (VV group). The possibility that BRO interacts with the development of dopamine mechanisms in the brain at different sensitive developmental periods, and thereby influences later behavior, is discussed.

Animals↗
PubMed1989

Perinatal bromopride treatment: effects on sexual behavior of male and female rats.

Effects of different perinatal bromopride treatments on sexual behavior were examined in adult male and female rats of Wistar origin. Female rats of mothers treated with bromopride (BRO) during lactation (VB group) and during pregnancy and lactation (BB group) showed lower lordosis quotients than those of controls (VV group). Females of mothers treated with BRO only during pregnancy (BV group) showed no differences in lordosis quotient when compared to the VV group. There were no significant differences in male sexual behavior between experimental and control groups. The effect of bromopride on the control of sexual behavior is discussed.

Animals↗
PubMed1989

Effects of long-term aldrin administration on seizure susceptibility of rats.

The effects of long-term administration of sub-convulsive doses of aldrin, an organochlorinated pesticide, on seizure susceptibility of rats were studied. Results show that treatment with the pesticide made the rats more susceptible to sound-induced seizures; an increment in post-seizure depression time after maximal electroshock administration was also observed in aldrin-treated animals. Aldrin administration displaced the control dose-response curves constructed for amphetamine and pentylenetetrazol to the left and right, respectively; no differences were detected between control and aldrin-treated rats for strychnine, picrotoxin or 3-mercaptopropionic acid. The results, discussed in the light of the effects of aldrin on biogenic amines or on the electrophysiology of neurones suggested an involvement of both noradrenergic and alteration excitability of the CNS with the observed increments on seizure susceptibility.

Acoustic Stimulation↗
PubMed1989

Is monofluoracetic acid the active neurotoxic principle in Palicourea marcgravii (St. Hill) leaves?

Acute intoxication of rats with the crude extract of Palicourea marcgravii (PM) and with monofluoracetic acid (MFA) solutions was compared since it has been reported that PM leaves contain monofluoracetates (455 micrograms/g air-dried material). The neurotoxic signs produced by oral administration of PM and MFA were similar and included tonic-clonic seizures. The dose-response curves constructed for the convulsant effects of PM and MFA were parallel and the CD50s were 630 mg/kg (508-781) and 0.90 mg/kg (0.76-1.06), respectively. These data suggest that the neurotoxic signs produced by PM are the consequence of MFA present in the plant leaves.

Animals↗
PubMed1989

Effect of a specific stress (aldrin) on rat progeny behavior.

The effect of dam exposure to aldrin, an organochlorinated compound (1.0 mg/kg, sc, daily), during pregnancy or lactation was studied in young rat pups (11, 15, 18 and 22 days of age) and in adult animals (90 days of age). Locomotor activity was significantly greater in both young and adult animals when compared to controls. Male rats that received aldrin during lactation also showed reduced plasma corticosterone levels. Maternal behavior was not affected by treatment during either period. The results suggest that aldrin may act as a perinatal stress factor.

Aldrin↗
PubMed1989

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 an open field to 8 +/- 8 and 5 +/- 5, respectively, when compared to 28 +/- 5 for control rats treated with vehicle only. The same doses of amitraz (N = 10 per group) increased duration of immobility to 80 +/- 50 and 113 +/- 64 s, respectively, when compared to 113 +/- 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. Amitraz 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 +/- 26, 120 +/- 29 and 198 +/- 58 min, respectively, when compared to 45 +/- 15 min for control mice treated with vehicle only. These results indicate that amitraz produces a depressant effect on the central nervous system.

Analysis of Variance↗
PubMed1988

Effects of single and long-term metoclopramide administration on open field and stereotyped behavior of rats.

The effects of single and long-term metoclopramide administration on rat open-field and apomorphine-induced stereotyped behavior were studied. A single dose of metoclopramide decreased dose dependently not only locomotion and rearing frequencies in the open field but also the apomorphine effects. Withdrawal from long-term metoclopramide administration induced a significant increase in all parameters of activity recorded in the open field. The responsiveness to apomorphine was also augmented in metoclopramide-withdrawn rats. These results were considered to be a consequence of the supersensitivity of central dopaminergic receptors.

Animals↗
PubMed1988

Effects of ovariectomy and of estrogen administration on some dopamine-related behaviors in the rat.

1. The effects of ovariectomy and of estrogen administration were determined on some dopamine-related behaviors. 2. Haloperidol withdrawal induced a progressive increase in locomotion and rearing frequencies of female rats observed in an open-field. This increase started earlier and was greater in ovariectomized than in sham-operated animals. 3. Repeated administration of increasing doses of 17-beta-estradiol (from 0.05 to 0.3 mg/kg once daily, for 28 days) significantly decreased apomorphine-induced stereotyped behavior in ovariectomized rats, 30 min after the last hormone injection. 4. Withdrawal from long-term 17-beta-estradiol administration increased the sensitivity of the animals to apomorphine. 5. These results suggest not only an antidopaminergic effect for estrogen but also a possible summation of estrogen and haloperidol withdrawal effects.

Analysis of Variance↗
PubMed1988

Alterations in the behavior of young and adult rats exposed to aldrin during lactation.

The effects of the administration of aldrin, an organochlorinated pesticide, during the period of lactation were studied on behavior of the litters. The general activity of the young and adult animals was tested in an open-field. In both situations, activity was higher in experimental than in control rats. Experimental animals also showed a higher performance in a hole-board apparatus and in the shuttle-box of two-way active avoidance learning. The results suggest that the insecticide is involved in alterations occurring in the nervous/endocrine systems of the newborn.

Aldrin↗
PubMed1987

Dopaminergic supersensitivity after long-term bromopride treatment.

The effects of bromopride administration on open-field and apomorphine-induced stereotyped behavior of rats were studied. Bromopride induced a displacement to the right of the control dose-response curve constructed for apomorphine stereotypes. Withdrawal from long-term bromopride treatment induced not only a significant increase in ambulation and rearing frequencies for male rats observed in the open-field but also an increased sensitivity of both male and female animals to apomorphine. The results are interpreted as a consequence of the development of supersensitivity of central dopaminergic receptors, probably of the mesostriatal pathways.

Animals↗
PubMed1987

Effects of d,l-propranolol on apomorphine induced stereotyped behavior in rats.

The effects of d,l propranolol on stereotyped behavior induced by apomorphine administration was studied quantitatively. d,l Propranolol caused a 2.5 leftward displacement of the control dose-response curve constructed to apomorphine-induced stereotypy; the ED50 for apomorphine was reduced from 1.87 +/- 0.38 to 0.74 +/- 0.17. The potentiation was dependent on both d,l-propranolol and apomorphine doses. Results are discussed in the light of a possible interference of the central noradrenergic systems with the expression of dopaminergic-induced stereotyped behavior.

Animals↗
PubMed1986

GABAergic influences on barbital withdrawal induced convulsions.

Animals which had been long-term treated with increasing concentrations of sodium barbital in the drinking water were killed 30 min or 72 hr after the last day of treatment, to determine striatal GABA levels and turnover rate. The effects of pentobarbital administration on GABA metabolism of rats withdrawn or not withdrawn from barbital were also studied. Barbital withdrawal induced a significant decrease in striatal GABA levels and also in the turnover rate after pentobarbital treatment. The latter effect was greater in rats killed 72 hr after drug removal. In control animals, pentobarbital treatment increased striatal GABA levels but did not affect the turnover rate. Barbital removal also made the rats less responsive to the effects of pentobarbital on striatal GABA levels. These results suggest the participation of a central GABAergic system in barbital withdrawal convulsions.

Animals↗
PubMed1986

Effects of d,1-propranolol and haloperidol on aggressive behavior induced in mice by isolation and isolation plus amphetamine treatment.

We measured the aggressive behavior of isolated mice treated or not with d,1-amphetamine (6.0 mg/kg, ip) and injected with different doses of d,1-propranolol (10.0, 20.0 or 30.0 mg/kg, ip) or haloperidol (0.5 or 1.0 mg/kg). d,1-Amphetamine (6.0 mg/kg, ip) decreased the aggressiveness of the isolated mice and induced stereotyped behavior. Haloperidol antagonized amphetamine-induced stereotypy, increased the latency to the 1st attack and decreased duration of fighting and frequency of attacks in mice treated or not with amphetamine. d,1-Propranolol did not change stereotypy but decreased aggressiveness in a dose-dependent way, being more effective against aggression induced by isolation per se. These results are discussed in terms of the interference of the drugs with the activity of either catecholaminergic neurons or midbrain reticular formation. The latter effect seems to be the most likely explanation for the observed anti-aggressive effects of haloperidol and d-1, propranolol.

Aggression↗
PubMed1985

Effects of d,l-propranolol on open field behavior of rats.

Rats were administered with different doses of d,l-propranolol or d,l-propranolol plus amphetamine before open-field observations. Results show that d,l-propranolol decreased locomotion and rearing frequencies and increased immobility duration in rats. An antagonism between the effects of amphetamine and d,l-propranolol on general activity of rats was also observed. Results are discussed in the light of a possible interference of the drugs with the activity of either noradrenergic neurons or mid-brain reticular formation.

Amphetamine↗
PubMed1985

Central nervous system supersensitivity and withdrawal from long-term treatment with barbital.

The effects of withdrawal from long-term treatment with increasing concentrations of sodium barbital in the drinking water were studied in rats. Animals were tested 72 hr after the removal of the drug. Withdrawal of barbital induced a significant leftward displacement of the dose-response curves obtained for the convulsive effects of strychnine, picrotoxin and 3-mercaptopropionic acid. The removal of the drug also made the rats more sensitive to convulsions elicited by sound. Baclofen and THIP were able to decrease the audiogenic response score of rats, withdrawn from barbital, in a dose-dependent way. These effects were interpreted to be a consequence of changes in the sensitivity of central GABAA and/or noradrenergic receptors induced by depression due to long-term administration of barbital.

Acoustic Stimulation↗