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Biomedical subjects

S Barron

Publications and source records attributed to S Barron.

At least 37 records · Page 2Linked to original sources
PubMed1996

Neonatal cocaine exposure and activity rhythms in rats.

This study looked at the effects of neonatal cocaine exposure on activity rhythms over a 48-h period in rats. Subjects were artificially-reared from postnatal days (PN) 4-10 via intragastric cannulas. The four treatment groups included two cocaine doses (20 and 40 mg/kg per day), an artificially-reared control and a normally reared suckled control. Subjects were tested at PN 38-40 in an automated running wheel. Neonatal cocaine exposure did not alter activity rhythms over the 48-h test period. However, there was a gender-specific effect of neonatal cocaine exposure on response to the novel test chamber and to the experimenter. The 20 mg/kg cocaine-exposed females showed increased running wheel activity relative to all other groups after placement in the running wheel. During the second 24-h period, cocaine-exposed females from both cocaine groups showed increased activity relative to controls following the entry of an experimenter to the test room. These findings suggest that female rats exposed to cocaine neonatally show an increased response to novel environments and stimuli.

Animals↗
PubMed1995

Behavioral effects of neonatal cocaine exposure using a rodent model.

This study examined the effects of neonatal cocaine exposure on behavior using a rodent model. Rat pups were implanted with intragastric cannulas on postnatal day (PND) 4 and artificially reared (AR) from PND 4-10. The AR groups included two cocaine doses (20 mg/kg per day and 60 mg/kg per day) and an AR control. A sham surgery control group was also included that was reared naturally by its dam. Offspring from these neonatal treatment groups were examined for suckling performance (PND 13), passive avoidance learning (PND 23-24), activity (PND 18-21), or spontaneous alternation (PND 21). Neonatal cocaine exposure had no effect on suckling measures or passive avoidance learning. Activity was increased in the 60 mg/kg per day cocaine group relative to controls. In addition, spontaneous alternation was delayed in the 20 mg/kg per day cocaine-exposed females relative to all other groups. These data suggest that neonatal cocaine exposure may alter performance on some relatively simple tasks. More work is clearly warranted to look at the effects of neonatal cocaine exposure on more complex behaviors.

Animals↗
PubMed1995

Effects of neonatal ethanol exposure on saccharin consumption.

Prenatal ethanol exposure has been associated with alterations in a variety of sexually dimorphic behaviors in rats. This study examined the effects of neonatal ethanol exposure on saccharin consumption, a sexually dimorphic behavior in rats. Subjects were Sprague-Dawley rats that were artificially reared (AR) from postnatal day (PN) 4-PN12 through gastrostomy tubes with ethanol exposure limited to PN4-PN10. The AR groups included two ethanol doses (6 g/kg/day and 4 g/kg/day) and an isocaloric maltose-dextrin control. A sham surgery control group was also included. The AR subjects were returned to their dams on PN13. At 21 days of age, subjects were housed with one same-sex sibling and free access to rat chow and water until testing. Subjects were tested for saccharin preference and consumption at 110 days of age. Typically, male rats consume less saccharin than females, and this was evident in the 4 g/kg ethanol group and both control groups. However, this was not apparent among the 6 g/kg ethanol-exposed males. Furthermore, saccharin preference seemed to be reduced in the females exposed to 6 g/kg ethanol. These data suggest that the "sensitive period" for ethanol's effects on sex differences in saccharin consumption extends into postnatal life.

Animals↗
PubMed1994

Anticonvulsant activity of calmodulin antagonist W-7 in convulsions induced by lindane and BayK-8644: effects in c-fos expression.

The anticonvulsant activity of calmodulin antagonist W-7, was investigated on convulsions induced in mice by the insecticide lindane and by the calcium channel agonist BayK-8644. We also studied the inhibitory effect of W-7 on on c-fos mRNA expression induced by both convulsants. We observed a good correlation between doses and the acute convulsive effects of lindane and BayK-8644. The incidence rate and time to onset were clearly dose-dependent. W-7 antagonized the convulsive effects of lindane and BayK-8644 in all the parameters studied. A significant decrease in the incidence rate and time to onset were observed when they are compared with the values obtained with the ED100 of lindane- and BayK-8644 induced seizures. Both were able to activate the mRNA expression of the proto-oncogene. The pattern of this expression displayed by in situ hybridization was very similar. A dramatic increase was found in dentate gyrus and high levels of mRNA expression also occurring in hippocampal fields and cortical regions. In accordance with the behavioural results, W-7 antagonized also the c-fos expression induced by lindane and BayK-8644. Our results suggest that lindane as BayK-8644 may activate voltage-dependent calcium channels leading to calmodulin activation.

3-Pyridinecarboxylic acid, 1,4-dihydro-2,6-dimethy↗
PubMed1993

Alterations in activity following alcohol administration during the third trimester equivalent in P and NP rats.

There is considerable variation in the consequences of alcohol abuse during pregnancy on infant outcome. Although it is clear that a number of factors contribute to this variability, one hypothesis that has received recent attention is the role of genetic differences in response to alcohol. This study examined activity levels in the alcohol-preferring (P) and alcohol-nonpreferring (NP) rats following neonatal alcohol exposure. Although these lines were selectively bred for differences in voluntary alcohol consumption, they also differ in their sensitivity and tolerance to alcohol. The P and NP offspring were artificially reared and administered ethanol (either 6 or 4 g/kg/day) from postnatal day 4 (PN 4) until PN 10 via intragastric cannula. An artificially reared isocaloric maltose group and a normally reared control group were also included. From PN 18 to PN 21, subjects were tested daily for 30 min in an automated activity monitor. Exposure to either the 4 or 6 g/kg dose of ethanol resulted in overactivity in P rats. However, only the 6 g/kg dose group displayed overactivity among the NP offspring. Furthermore, the level of overactivity displayed by the alcohol-exposed P rats was significantly greater than that displayed by the alcohol-exposed NP rats. These data suggest that genetic differences in response to alcohol may be a predictor for the behavioral teratogenic effects of alcohol.

Alcohol Drinking↗
PubMed1991

Neonatal alcohol exposure alters suckling behavior in neonatal rat pups.

Prenatal alcohol exposure has been associated with a variety of suckling deficits in both humans and animals. In this study, the effect of neonatal alcohol exposure on suckling performance was examined in 15-day-old rat pups. Neonatal alcohol exposure has been used as a model to study the effects of alcohol exposure during a period equivalent to the human third trimester with respect to brain growth. Subjects were Long-Evans rats which had been artificially reared (AR) and fed through gastrostomy tubes from postnatal day (PN) 4-PN 12. The AR groups included two groups given ethanol doses of 6 g/kg/day or 4 g/kg/day and an isocaloric maltose-dextrin control group. A suckled control group raised by their natural mothers was also included to control for artificial rearing. Fifteen-day-old pups were individually placed with an anesthetized dam for a 1-h videotaped test session. Pups in the 6 g/kg alcohol group took longer to attach to the nipple and spent less time suckling than pups from all other treatment groups. Nipple-shifting behavior was disrupted in all artificially reared groups, but it was most severely affected in the 6 g/kg group. These findings suggest that neonatal alcohol exposure interferes with suckling performance and these altered behaviors may contribute to the postnatal growth deficits that have been reported following alcohol exposure in utero.

Animals↗
PubMed1991

Effects of peanut butter on ruminating.

Barton and Barton (1985) reported that supplementary peanut butter reduced rates of ruminating of 4 children with mental retardation and hypothesized that the effect was due to its thick, sticky consistency. We further examined the effects of peanut butter with 5 subjects with mental retardation by independently manipulating the caloric density versus the consistency associated with peanut butter. Results showed an inverse relation between rates of ruminating and amount of peanut butter consumed. However, this effect appeared to be primarily due to an increase in calories. A weaker and less consistent effect was ascribed to the consistency of peanut butter.

Adult↗
PubMed1990

Effects of cimetidine and ranitidine on basal gastric pH, free and total acid content in pigs.

The effects of intramuscular administration of multiple doses of cimetidine and ranitidine on basal gastric pH, free and total acid content from young adult pigs were studied. Cimetidine (4.5 mg kg-1, four times a day, intramuscularly, for three days) significantly (P less than 0.05) raised the basal gastric pH above 3.5 with a simultaneous reduction in free acid content at two, three and 26 hours after the administration of the eighth dose. Ranitidine (0.75 mg kg-1, four times a day, intramuscularly, for three days) significantly (P less than 0.05) raised the basal gastric pH above 3.5 with a concomitant reduction in free acid content at three and 38 hours after the administration of the eight dose. Neither cimetidine nor ranitidine had any significant effects on total acid content. These results confirm that the pig is a basal acid secretor and that the pharmacodynamics and pharmacokinetics of cimetidine and ranitidine in pigs might be different from those in humans.

Animals↗
PubMed1989

The effects of long-term lead intoxication on the nervous system of the chicken.

In order to study the possible etiologic role of lead in human motor neuron disease we produced chronic lead intoxication in the chicken by daily administration of lead acetate. Control animals received sodium acetate. During life, periodic measurements were made of motor function, motor nerve conduction velocity and response amplitude. After sacrifice, histologic analysis was performed on spinal cord, peripheral nerve and muscle. A syndrome was produced characterized by a fall in motor response amplitude, spinal motor neuron degeneration, motor axonal loss and atrophy of muscle, similar to that seen in human motor neuron diseases.

Animals↗
PubMed1988

Effects of prenatal alcohol exposure on the sexually dimorphic nucleus of the preoptic area of the hypothalamus in male and female rats.

Prenatal alcohol exposure can produce a variety of behavioral and physiological alterations, including changes in sexually dimorphic behaviors. It has been proposed that alcohol alters these behaviors by altering prenatal androgen and/or other steroid levels. This study was designed to examine the effects of prenatal alcohol exposure on a sexually dimorphic neuroanatomical structure, namely, the sexually dimorphic nucleus of the preoptic area of the hypothalamus (SDN-POA). This nucleus is larger in males than females and is sensitive to perinatal sex steroid exposure. The SDN-POA was examined in 70-80-day-old male and female rats whose mothers received on days 6-20 of pregnancy either a liquid diet containing 35% ethanol-derived calories (EDC) or a 0% EDC isocaloric pair-fed liquid diet. An ad libitum lab chow control group was also included (LC). Both volume and average cell size of the SDN-POA were markedly smaller in alcohol-exposed males relative to 0% EDC and LC controls. In contrast, prenatal alcohol exposure did not appear to affect SDN-POA volume or cell size in females. Prenatal alcohol exposure did not significantly alter the volume of a nearby nucleus, the nucleus of the anterior commissure, in either sex. These findings support the hypothesis that prenatal alcohol exposure alters sexual differentiation in males, perhaps by altering some aspect of the prenatal androgen environment. The absence of any effect in 35% EDC females suggests that males and females may be differentially sensitive to alcohol's effects on this nucleus.

Animals↗
PubMed1987

Prenatal alcohol exposure: recent work on behavioral dysfunctions in pre-weanling rats.

This article reviews recent data collected in our laboratory examining the behavioral effects of prenatal alcohol exposure in pre-weanling rats. The behavioral alterations which are discussed include suckling dysfunctions, overactivity, and early learning deficits. Similar behavioral dysfunctions have also been reported in children exposed to alcohol during prenatal development. These similarities are discussed as well as possible insights that might be gained from animal models of fetal alcohol effects.

Animals↗