bluuebunny/crossref_metadata_2025 huggingface dataset:
A‐80426, a potent α2‐adrenoceptor antagonist with serotonin uptake blocking activity and putative antidepressant‐like effects: I. Biochemical profile
Authors: Hancock Arthur A. , Buckner Steven A. , Oheim Karen W. , Morse Patricia A. , Brune Michael E. , Meyer Michael D. , Williams Michael , Kerwin James F.
Published: January 2005

A‐80426 (N‐[2‐(benzofuran‐6‐yl)ethyl]‐N‐[(R)−( + )‐5‐methoxy‐1,2,3,4‐tetrahydronaphthalen‐1‐yl methyl]‐N‐methylamine) is a novel compound with potential antidepressant activity. A‐80426 inhibits synaptosomal serotonin (5HT) uptake (IC50 = 13 nM) more potently than fluoxetine (IC50 = 308 nM), and blocks [3H]‐paroxetine binding (K1 = 3.8 nM) to 5HT uptake sites. A‐80426 inhibits [3H]‐rauwolscine binding to α2‐adrenoceptors (K1 = 2.0 nM), blocks α2‐adrenoceptors (pEC30 = 7.4–7.5) in electrically stimulated rat atria and vas deferens, and increases electrically stimulated [3H]‐NE overflow from brain slices. A‐80426 lacks significant activity at isolated tissue models of α1‐ or β‐adrenergic sites or at M3 muscarinic or H1 histaminergic receptors. A‐80426 has negligible radioligand binding activity at 5HT1 and β‐adrenergic receptors, but exhibits a K1 value of 144 nM at 5HT2 receptors. A‐80426 interacts with both dopamine D1 (K1 = 744 nM) and D2 (K1 = 51.5 nM) receptors. Functionally, the compound antagonizes dopamine‐induced changes in cyclic AMP formation with K1 values of 133 nM and 185 nM at D1 and D2 receptors, respectively. The potent α2‐adrenoceptor blocking activity of A‐80426 in radioligand binding assays is not reflected in isolated tissue bioassays, and may thus have less functional consequence in determining the in vivo profile of the compound. Accompanying behavioral data [Giardina et al., 1995], while indicating activity in the olfactory bulbectomized rat model of antidepressant action, shows a marked reduction in the α2‐antagonistic properties of A‐80426 in other in vivo models, suggesting that the antidepressant‐like activity may be caused primarily by inhibition of 5HT uptake. © 1995 Wiley‐Liss, Inc.
Nitric oxide‐associated vasorelaxing effect of an anti‐ulcer agent, benexate hydrochloride betadex
Authors: Iwasaki Takanori , Matsunaga Kazuki
Published: January 2005

The vasorelaxing effect of benexate hydrochloride betadex (BHB) was examined in rat thoracic aortic ring with and without endothelium. BHB at 1∼100 μM caused concentrationdependent vasorelaxation in both endothelium‐intact and ‐denuded aortas precontracted with phenylephrine (1 μM), with its relaxing effect being significantly more potent in the endotheliumintact aorta. This partial endothelium‐dependent vasorelaxation by BHB was significantly inhibited by Nω‐nitro‐L‐arginine methylester (100 μM), an inhibitor of nitric oxide (NO) synthase, and hemoglobin (10 μM), an NO scavenger, but not by indomethacin (5 μM), an inhibitor of cyclooxygenase. The content of c‐GMP, a second messenger of NO, in endothelium‐intact aorta treated with BHB (30 μM) significantly increased by about twofold of the control level. NO synthase (NOS) activity by the treatment of BHB at 100 μM increased to about the same level by the treatment of L‐arginine at 10 μM. Taken together, these results suggest that the vasorelaxing effect of BHB is, in part, associated with NO synthesis and release from the endothelium but not with the prostaglandin system. The mechanism of NO synthesis and release from the endothelium by BHB might be NOS activation by the effect as a substrate of NOS. © 1995 Wiley‐Liss, Inc.
Antiarthritic mechanisms of lupeol triterpenes
Authors: Kweifio‐Okai George , De Munk Fred , Macrides Theodore A. , Smith Phil , Rumble Baden A.
Published: January 2005

The triterpenes lupeol (L), lupeol‐3‐palmitate (LP), and lupeol‐3‐linoleate (LL) have previously been shown to reduce joint destruction in adjuvant arthritic rats. In order to explain the relative antiarthritic effectiveness (LL>LP>L), the triterpenes were tested on the release of collagenase by rat osteosarcoma (bone tumor) cells, on the release of 5 lipoxygenase inflammatory products by human neutrophils, and on CCl4‐induced hepatotoxicity in rats. The rat osteosarcoma cells released collagenase which digested type I (bone) native collagen. The collagenase release, unaffected by 50 μM lupeol, decreased in the presence of lupeol linoleate and lupeol palmitate by 97% and 78%, respectively. The 30% inhibitory concentrations (IC30) of lupeol linoleate, lupeol palmitate, and lupeol on LTB4 release by the neutrophils were 27 μM, 94 μM, and μ100 μM, respectively. All the triterpenes equally reduced hepatic fatty degeneration in CCl4 rats, but only the triterpene esters significantly reduced LDH release (34% LL; 25% LP) and accelerated hepatic cell regeneration (LL>LP). The effectiveness of the triterpenes in the models of inflammatory and arthritic processes employed here corresponded with their relative antiarthritic effectiveness in adjuvant arthritic rats. © 1995 Wiley‐Liss, Inc.
Effects of typical, atypical, and novel antipsychotic drugs on amphetamine‐induced place conditioning in rats
Authors: Hoffman Diane C. , Donovan Hilary
Published: January 2005

Because amphetamine‐induced place conditioning is believed to be mediated by dopamine (DA) receptors within the nucleus accumbens, this behavioral model may be useful for detecting drugs with antipsychotic efficacy. To test the selectivity and specificity of the model, the present study examined whether amphetamine‐induced place conditioning is reversible in rats pretreated with the classical antipsychotic haloperidol, the atypical antipsychotic clozapine, and the novel antipsychotics raclopride and risperidone. The non‐antipsychotic drugs baclofen and prazosin were also tested. Male Sprague‐Dawley rats received d‐amphetamine (5.4 μmol/kg ip) paired with one side of a two‐compartment box and saline paired with the other side. During these pairings, locomotor activity was measured. On the test day, the amount of time drug‐free rats spent in each compartment was determined. Rats trained with amphetamine alone showed a significant increase in time spent on the drug‐paired side from pre‐ to postconditioning, indicating a place preference. Pretreatment with the highest dose of either haloperidol (0.026, 0.13, 0.26 μmol/kg sc), clozapine (3, 15, 30, 60 μmol/kg sc), raclopride (0.1, 0.2, 1.0 μmol/kg), or risperidone (0.12, 0.24, 1.2 μmol/kg sc) prior to amphetamine significantly blocked the establishment of place conditioning. Treatment with the antipsychotic alone did not support place conditioning (preference or aversion). On conditioning days, haloperidol, clozapine, raclopride, and risperidone significantly decreased amphetamine‐induced locomotor activity. Pretreatment with either baclofen or prazosin failed to disrupt amphetamine‐induced place conditioning despite significant decreases in locomotor activity on the conditioning days. These data provide preliminary support for amphetamine place conditioning as a rodent model for detecting drugs with antipsychotic efficacy. © 1995 Wiley‐Liss, Inc.
Development of gross electrical activity in the hippocampus of the guinea pig
Authors: Stenberg Dag , Vehaskari Matti
Published: January 2005

Hippocampal and neocortical EEG activity was recorded from 48 unanesthetized, intra‐uterine, guinea‐pig fetuses of 35 to 65 days gestational age. The earliest hippocampal electrical activity appeared at around 35 days (i.e., at approximately the same time as such activity appears in the lower brain stem, and earlier than it appears in the neocortex). This indicates that functional maturation of the brain begins almost simultaneously in large parts of the so‐called old brain, not only in its bulbar parts, and spreads to more superficial structures with age. The first activity had a random frequency distribution, whereas more regular periodicity developed later. From 44 days hippocampal bursts and spindles were recorded, especially during hypoxia or fetal distress. The bursts seemed to bear a relation to the reanimation process after hypoxia.
Some amino acids in the developing visual system
Authors: Davis J. M. , Himwich W. A. , Agrawal H. C.
Published: January 2005

Glutamic acid, glutamine, GABA, aspartic acid, and alanine have been determined throughout the ontogenetic development of the rabbit visual system, i.e., occipital cortex, superior colliculi, lateral geniculate bodies, and retina. At 11 days of age, when the rabbits' eyes were opening, many of the amino acids had decreased significantly in the individual parts, and then later increased to more mature levels. The amino acid level appeared to be fully developed by 30 days of life with glutamic acid having the highest concentration in the cortical area and GABA in the subcortical ones.
Norepinephrine and dopamine in the developing chick brain
Authors: Kobayashi Kenichi , Eiduson Samuel
Published: January 2005

Appearance, concentration, and distribution of catecholamines (dopamine and norepinephrine) in embryonic and postnatal chick brain regions were studied. The highest amount of DA was found in cerebral hemispheres and increased gradually to adult levels, whereas in other parts of the brain the concentrations of DA fluctuated during the post‐hatch period. The remainder contained the largest amount of NE, whereas the cerebral hemispheres contained relatively small amounts of NE. Relatively high amounts of NE were found in the cerebellum. A single dose of L‐3, 4‐dihydroxyphenylalanine (DOPA) injected into the 3‐day‐old embryo had no significant effect upon the levels of DA and NE either in the embryonic stages or in the postnatal period. In the 7‐day‐old chick, combined treatment of JB‐516 (catron) and L‐DOPA (IP) induced about a 10‐fold and 2‐fold increase of the brain level of DA and NE respectively about 30 min after injection, and these levels decreased rather rapidly within 2 hr. A group of chicks injected with DOPA at the 3‐day‐old embryonic stage and a group injected with saline were exposed one month post‐hatch to three visual discrimination tasks. There was no significant difference in the performance between these two groups.
The effects of separation and reunion on the behavior of mother and infant squirrel monkeys
Authors: Kaplan Joel
Published: January 2005

Mother and infant squirrel monkeys that lived together in a socially restricted environment were separated for a period of seven days after the infants had become relatively independent, and were then reunited. Behavioral observations before, during, and after separation indicated that (1) female infants became independent of their mothers earlier than males, (2) neither mothers nor infants were severely affected by separation, and (3) an increase in attachment occurred following reunion only when the mother had a limited history of maternal experience. These results suggest that (1) certain characteristics in the maternal behavior of the squirrel monkey facilitate readjustment in mothers and infants following maternal separation, (2) maternal experience can influence the mother‐infant relationship following a period of separation, and (3) the independence of infants from their mothers may be a function of both sex and species.
Elevated catecholamines in thirty‐day‐old chicken brain after depletion during development
Authors: Sparber Sheldon B. , Shideman Frederick E.
Published: January 2005

The effects of prenatal reserpine administration upon uptake of tritiated norepinephrine (H3‐NE) by newly hatched chick brain suggests an interference of catecholamine (CA) uptake and/or binding. The relationship between fluorescence from CA and the radioactivity from H3‐NE approached unity in the control group where no such relation was seen in the reserpine treated group. Moreover, 30 days after hatching, CA levels in whole brain of chicks hatched from drug‐injected eggs were significantly higher than vehicle‐injected controls. However, reserpine did cause a slight but significant elevation of total protein in 14‐day‐old embryo brain. These data support the hypothesis that ontogenetic alteration of systems exhibiting end‐product inhibition can be of a long‐lasting, perhaps permanent nature. The direction of change in CA 30 days after hatching, opposite to the change induced pharmacologically during development, is additional support for the concept of „thermostat”︁ type regulation of enzyme activity being determined by product concentration at critical periods during development.
Interaction of genotype and environment as determinants of corticosteroid response to stress
Authors: Treiman David M. , Fulker D. W. , Levine Seymour
Published: January 2005

The temporal pattern of plasma corticosterone concentrations following electric shock was studied in 10‐week old mice from two inbred strains (C57BL/10J and DBA/2) and their reciprocal crosses, half of which had been subjected to infantile stimulation. The roles of genotype, maternal factors, and handling were assessed as determinants of corticosteroid response to stress. Highly significant and opposing genetic and maternal effects interacted to limit extreme plasma corticosterone concentrations following stress. Infantile stimulation also acted to produce intermediate steroid responses.
Development of cortical spreading depression and of its transition to the caudate nucleus in rats
Authors: De Luca Bruno , Bureš Jan
Published: January 2005

The development of Leão's spreading depression (SD) of electroencephalographic activity was studied in young rats by recording the accompanying slow potential changes (SPC). The propagation rate of cortical SD increased from 1.65 mm/min on Day 15 to 2.6 mm/min on Day 20; the increase of SPC amplitude and the decrease of SPC duration were less evident over the same period. The SD elicited in the caudate nucleus by microinjections of KCl did not spread to neocortex in 20‐ and 30‐day‐old rats and transition occurred in only 5% of KCl applications in 40‐day‐old rats. Application of a pyrrolopyrimidine derivative (BW 57–271; 5 mg/kg) increased the cortico‐caudate SD transition to 100% in rats aged 20 days or older and increased the SPC amplitude in both structures. The development of SD parameters can be ascribed to dendritic growth and to the decrease of extracellular space; the cortico‐caudate propagation block can be ascribed to morphological immaturity of the transitional zone.
Interactive effects of parity and pup stress on the maternal behavior of Rattus norvegicus
Authors: Wright Linda L. , Bell Robert W. , Schreiber Henry L. , Villescas Ramiro , Conely Lynn
Published: January 2005

Litters of primiparous and multiparous rat mothers received 0, 2, or 5 min of cold stress for the 1st 5 days postpartum. Primiparae showed increasing maternal responsiveness over the treatment period. Multiparae were initially maternally responsive to moderate stress cues from pups, but habituated to them over days. From Days 6 to 20, when pups were not stressed, lactation behavior of stressed groups declined in primiparous mothers but not in multiparous mothers.
Ontogenetic changes in pup‐elicited maternal pituitary‐adrenal activity: Pup age and stage of lactation effects
Authors: Smotherman William P. , Mendoza Sally P. , Levine Seymour
Published: January 2005

Ontogenetic changes in pup‐elicited maternal corticosterone responsiveness were investigated. Patterns of maternal corticosterone change were found to depend on pup treatment: shocked pups elicited larger corticosterone elevations than pups that had been handled. In addition, both the age of the stimulus pups and the stage of lactation when the mother was tested affected the pattern and magnitude of maternal pituitary‐adrenal activity.
Olfactory discrimination of squirrel monkey mothers by their infants
Authors: Kaplan Joel N. , Cubicciotti Daniel , Redican William K.
Published: January 2005

Infant squirrel monkeys, 8 to 24 weeks of age, were tested for their ability to discriminate their own mother from another lactating mother by means of olfactory cues, visual cues, or a combination of both. Discrimination by olfactory cues was unequivocal. Addition of static visual cues did not enhance discrimination, and infants showed little evidence of discriminating the mother by means of static visual cues alone. These results suggest that olfaction may be a more significant factor in primate early attachment than has generally been assumed.
Vocal output in preterm infants
Authors: Beckwith Leila , Sigman Marian , Cohen Sarale E. , Parmelee Arthur H.
Published: January 2005

Data on vocal output of 51 preterm infants and 16 term infants were obtained during naturalistic home observations ast 1, 3, and 8 months; during the administration of a preference‐for‐novelty paradigm in the laboratory at 8 months; and by the administration of the Gesell Developmental Schedules at 9 months. Preterm and term infant groups were found to show both similarities and differences: both groups vocalized a similar amount in the preference‐for‐novelty situation; both groups earned similar scores on the language subtest of the Gesell; both groups increased and percentage of awake time they spent in nondistress vocalization from 1 to 8 months. Term infants showed an earlier increase than did preterm infants: term infants significantly increased during the 1–3‐month period, whereas preterm infants only increased significantly during the 3–8‐month period. The developmental differences suggest a link between vocal output and perinatal conditions in that caregiver behavior was not found to be different among groups. Within the preterm groups, some relationships were found between vocal output and later test performance: infants who vocalized more during mutual gazing with the mother earned significantly higher scores on the language subtest of the Gesell.
Acquisition and retention of a passive‐avoidance task as a function of age in mice
Authors: Nagy Z. Michael , Thaller Karen , Mazzaferri Timothy A.
Published: January 2005

In Experiment I groups of mice between 16 to 100 days of age were tested for retention of a passive‐avoidance response between 1 min and 96 hr following a single training trial at 2 shock intensities. In general, although almost all age groups displayed reliable retention at all retest intervals, some retention losses were found among the youngest age groups at the longer retention intervals. Higher shock intensity resulted in longer retest latencies, primarily among the youngest mice. In Experiment II mice 16, 25, and 100 days of age were trained to criterion on the passive‐avoidance task and retested on a single trial following retention intervals of 24, 96, 192, and 384 hr. Young mice exhibited severe retention losses relative to 100‐day‐old mice at the longer intervals, even though they did not show deficiencies in acquisition. Neurological maturity at the time of original training appears to account for the age‐related memory differences.
Ultrasound by mouse pups from deaf and hearing strains
Authors: Verhaeghe Arlette , Noirot Eliane
Published: January 2005

Pups aged 1 to 10 days, of deaf and hearing mouse strains, were monitored with an ultrasound detector while submitted to standard conditions of cold, isolation, and retrieving. The number of detections varied with the age of the pups and with the type of treatment (as established previously) but not with the genotype of the pups. Thus, occurrence and changes with age in ultrasound emission do not seem to be greatly influenced by their effects upon adult behavior.
Relative aversion thresholds for shock in infant mice
Authors: Michael Nagy Z. , Murphy James M. , Ray Donald
Published: January 2005

Using a spatial‐preference technique, we tested separate groups of mice, 5, 7, 9, 11, 13, and 15 days of age, for escape and avoidance of a range of shock intensities administered from AC constant current and fixed impedance shock sources. With intensities ranging from 0 to .2 mA and to 70 V for the respective sources, near asymptotic escape and avoidance were obtained at .1 mA and at 50 V for all ages tested. Although few differences in the relative aversiveness of particular shock intensities were noted across ages with each source, the fixed impedance source produced more consistent avoidance than did the constant current source. The findings suggest that the motivational properties of shock remain relatively constant throughout the early development of the mouse and that the technique employed in this study should prove useful in assessing possible age‐related alterations in sensitivity to shock as a result of physiological or pharmacological manipulations.
S‐100 protein: Regional CNS concentrations in rats raised in different environments
Authors: Perez Vernon J. , Thach Barbara B. , Palet James L.
Published: January 2005

The S‐100 protein was measured in 7 discrete brain areas from rats raised in an enriched, social, or isolated environment for 21, 42, or 84 days after weaning. S‐100 was measured at significantly higher concentrations under enriched than under social environmental conditions in cerebellum and brainstem at 21 days but not thereafter. The protein in corresponding areas of brain in isolates was significantly less concentrated than in social controls. The results suggest changes, in turnover of the protein as a result of stimulation and activation of functionally specific brain regions, of the animals' responses to and interaction with environmental stimuli and adaptation to those stimuli.
A neuropharmacological analysis of central nervous system catecholamine systems in developmental protein malnutrition
Authors: Leahy J. P. , Stern W. C. , Resnick O. , Morgane P. J.
Published: January 2005

Four experiments were performed to evaluate the effects of developmental protein deprivation on the behavioral response of adult rats to treatments known to affect central nervous system catecholamine systems. Results showed no group differences between protein malnourished and control animals in locomotor responsiveness to d‐ or l‐amphetamine, recovery from behavioral asymmetry produced by a unilateral lesion of the substantia nigra, or in the development of response patterns indicative of denervation supersensitivity. However, a dose‐dependent diminution in the ability of apomorphine to produce stereotyped behavior was noted in the malnourished group, suggesting that a class of brain dopamine receptors may be impaired or may have undergone homeostatic modification as a result of the undernutrition procedure.
Behavioral effects of neonatal thyroid hormones and differential postweaning rearing in rats
Authors: Sjödén Per‐Olow , Lindqvist Mats
Published: January 2005

Male and female rats (T rats) given an injection of 75 μg tri‐iodothyronine (T3) and 25 μg thyroxine (T4) on Day 3 after birth were raised under enriched (E) and impoverished (I) postweaning conditions. Observations of their open‐field behavior on Days 63 and 112 revealed a higher rate of activity in T groups as compared to controls (C) as well as faster running times and more entries/min in Hebb‐Williams maze testing on Days 74–86, indicating behavioral hyperactivity in T rats. Active‐avoidance testing at age 91 days revealed a higher number of intertrial crossings and significantly faster unconditioned response and conditioned response latencies in T as compared to C groups. Enriched postweaning rearing altered the behavioral effects in T rats comparatively little, least in the open‐field and more so for escape‐ and avoidance‐latencies and for the number of errors in the Hebb‐Williams maze.
Exploration in immature rats: Effects of drugs
Authors: File Sandra E.
Published: January 2005

The effects of d‐amphetamine (4 mg/kg), scopolamine (1 mg/kg), methylscopolamine (1 mg/kg), and parachlorophenylalanine (400 mg/kg) on exploration were studied in male rats at 16, 21, and 28 days of age. Amphetamine elicited stereotypy at all ages tested, reduced exploration (measured by the time spent head‐dipping during a 10‐min trial in a holeboard) from Day 21, but did not significantly increase rearing at the ages tested. (Reduced head‐dipping, accompanied by stereotypy, is the pattern of results previously seen in adult rats with this dose of amphetamine.) An interesting difference emerged with scopolamine, which reduced head‐dipping at all the ages tested, whereas in adults it produced an increase. The age‐related difference in drug effects suggests that muscarinic pathways are functioning from Day 16, but that the system concerned with exploration functions differently in mature and immature rats. Both scopolamine and methylscopolamine reduced rearing which suggests that the change is due to peripheral actions of the drugs. Parachlorophenylalanine, which decreases serotonin levels, increased head‐dipping, as it has been found to do in adult rats.
Influence of age and short‐term starvation on the ATPase activity in the developing rat brain
Authors: Mourek J. , Šťastný F.
Published: January 2005

Na+‐K+‐stimulated and Mg++‐dependent ATPase activities were investigated in the developing cerebral cortex, subcortical structures, and medulla oblongata of rats as was the effect of 24‐hr lasting starvation and thirst on those enzyme activities. We found (a) a developmental increase of these ATPase activities in the developing rat brain with the maximum in the cerebral cortex and with the minimum in the medulla oblongata; (b) a decrease of the ratio of these enzyme activities, which was near unity in adult animals; (c) an increase of ATPase activities in the cerebral cortex and subcortical formations of young rats under starvation conditions followed by a decrease of the Mg++/Na+‐K+‐ATPase activity ratios in these structures; and (d) a decrease of these activities, especially in the cerebral cortex, and an increase of the activity ratios in adult animals under starvation conditions.
Early selective visual experience and pattern discrimination in hooded rats
Authors: Corrigan James G. , Carpenter David L.
Published: January 2005

The early visual experience of hooded rats was restricted to either vertical or horizontal stripes. In a discrimination task pairing a gray surface and stripes of either the same orientation or an orientation orthogonal to that experienced during rearing, the rats made significantly fewer correct choices with the orthogonal orientation. However, the relatively lower overall performance of the vertically reared‐horizontally tested animals was a major factor in the main effect of testing condition. We conclude that functional modification of the rat visual system through early selective visual experience is possible.
Failure of severe maternal stress or ACTH during pregnancy to affect emotionality of male rat offspring: Implications of litter effects for prenatal studies
Authors: Chapman Robert H. , Stern Judith M.
Published: January 2005

Daily maternal neck restraint, whole body restraint, hyperthermia, and ACTH treatment during the last 3rd of gestation had no reliable effect on open‐field and cage‐emergence behavior in male Sprague‐Dawley offspring. Many of these treatments, however, produced considerable maternal pathology and evidence for maternal adrenocorticoid release. Significant litter effects were found for almost every morphological and behavioral measure. Failure to control for the litter variable may account for many previously reported effects of prenatal stress on emotionality in rats. Female rats showed greater activity and less defecation than males on postpubertal open‐field and cage‐emergence tests.
Parental environment: Effects on survival, growth and aggressive behaviors of 2 rodent species
Authors: McCarty Richard , Southwick Charles H.
Published: January 2005

The influence of the parental environment on the development of aggressive behaviors was studied in 2 muroid rodent species. Litters of southern grasshopper mice and northern white‐footed mice were reared by the natural parents or were reciprocally cross‐fostered soon after birth to parents of the opposite species. After weaning at 24–26 days, mice of both species were isolated and observed at 10‐day intervals from 30 to 100 days of age in one of the following tests: (1) predation on house crickets; (2) interspecific aggression toward Swiss‐Webster laboratory mice; and (3) intraspecific aggression toward opponents of the same gender and approximate age. Naturally reared grasshopper mice males and females displayed extremely high levels of aggressive and predatory behaviors whereas white‐footed mice controls were passive and defensive in all tests. Rearing by white‐footed mice foster parents resulted in a significant decrease in the aggression of grasshopper mice males and females toward laboratory mice. During intraspecific encounters, fostered grasshopper mice initiated fewer social interactions than naturally reared controls. The predatory behavior of grasshopper mice was not altered by the fostering procedure. The behavioral measures of fostered white‐footed mice showed no systematic changes when compared to controls. These results indicate that the postnatal parental environment contributes to the naturally high levels of aggressive behaviors of grasshopper mice. In contrast, the limited aggressive behaviors of a naturally passive species, white‐footed mice, were not increased by fostering at birth to parents of a highly aggressive species, grasshopper mice.
Ontogenesis of human brainstem evoked potential amplitude
Authors: Salamy A. , Fenn C. Birtley , Bronshvag M.
Published: January 2005

Brainstem evoked potentials (BEP's) were studied in human subjects ranging in age from birth to adulthood.

The BEP's were recorded from the surface of the scalp referenced to either ear while brief clicks were delivered binaurally through earphones. Separate analyses of variance were computed for the peak‐to‐peak amplitude of each component of the BEP. Significant age effects were observed documenting the strong relationship between human brainstem development and amplitude changes in the BEP. The independent maturation of these structures was reflected by the significant interaction between age and peaks. Despite small fluctuations in the maturational curve of each peak, strong linear and quadratic trends were apparent.

The research presented here provides evidence of significant amplitude changes in the BEP accompanying human development. These findings indicate that brainstem maturation is not yet complete at birth and that the components believed to represent spatially separate generators in the auditory system show distinct maturational stages.
Early experience facilitates the development of temperature regulation in the cat
Authors: Jensen Robert A. , Davis Joel L. , Shnerson Allan
Published: January 2005

Thirty kittens were given a 30‐min exposure to a moderately cool environment and drop in body temperature was measured. One group was tested every day from age 2 days to 21 days of age. A 2nd group was tested on Days 6–21 and a 3rd group tested only at 19 days of age. The 1st group (tested on Days 2–21) became homeothermic at an earlier age than did the other groups. The data are interpreted to indicate that early exposure to cool temperatures facilitates acquisition of temperature regulation in the cat, and that observed deficits in passive avoidance learning in young cats are not due to increased motor activity produced by a fall in body temperature.
Effects of number of pre‐exposures on sucrose taste aversion in weanling rats
Authors: Franchina Joseph J. , Domato Gary C. , Patsiokas Ann T. , Alan Griesemer H. Alan
Published: January 2005

Weanling rats, 20 days old, received 0, 1, 2, 4, or 8 pre‐exposures to 12% sucrose prior to a single pairing of sucrose with an intraperitoneal injection of lithium chloride (LiCl; 3.0 mEq of a .15Msolution) or distilled water (20 mg/kg). Testing for sucrose taste aversion with a 2‐bottle‐choice procedure on 9 test trials reliably showed that increasing numbers of pre‐exposures to sucrose directly attenuated taste aversion effects in the LiCl‐injected groups but did not appreciably affect intake performance in the distilled water‐injected groups. Comparisons between the injection conditions yielded reliable evidence for sucrose taste aversion at each pre‐exposure level. These results show that flavor stimulus pre‐exposures reliably attenuate subsequent taste aversion in weanling rats as had previously been reported for adult rats.
Alterations in the maternal behavior of rats rearing hypothyroid and hyperthyroid offspring
Authors: Johanson Ingrid B.
Published: January 2005

To determine whether maternal behavior could serve as a mediator for thyroid hormone effects on behavior, I assessed nesting, nursing, grooming, contact, and retrieval in mothers of hypothyroid, hyperthyroid, and control litters, as well as in mothers of litters receiving thyroxine replacement therapy. Females assigned to the hypothyroid and replacement therapy treatments were placed on a goitrogenic diet of 2% propylthiouracil from Day 15 of gestation to Day 22 postpartum. Hyperthyroid and replacement therapy pups were injected daily with thyroxine starting on the day of birth. The decline in nesting and nursing was delayed in hypothyroid litters whereas the decline in nesting was accelerated in hyperthyroid litters. Retrieval was not affected, but grooming of pups occurred less frequently in hypothyroid and replacement therapy litters. Maternal care received by hypothyroid pups was considered adequate. Maternal behavior may alleviate some of the effects of perinatal hypothyroidism, but does not seem to be responsible for the more severe effects of hypothyroidism.
Pathways between constitution and competence during the 1st 5 years of life
Authors: Inoff Gale E. , Halverson Charles F. , Allen Martin G. , Cohen Donald J.
Published: January 2005

A global measure of newborn constitutional adequacy was found to be positively related to competent functioning at the age of 5–6 years. In a sample of 15 boys and 5 girls, newborn constitutional adequacy was related to aspects of focused (versus unfocused) activity, outgoingness, cognitive and verbal ability, and motor skill at the early childhood follow‐up. Additionally, some preschool data were available on most of the sample and continuity of competent functioning was traced across the 3 age periods. Also, hyperactive behaviors at the preschool period had negative implications for functioning in early childhood.
Development of home orientation in hypothyroid and hyperthyroid rat pups
Authors: Johanson Ingrid B. , Turkewitz Gerald , Hamburgh Max
Published: January 2005

In order to assess the effects of perinatal hypothyroidism or hyperthyroidism on the development of an integrated behavioral response, we tested hypothyroid, hyperthyroid, and control pups, as well as pups receiving thyroxine replacement therapy, for the development of the home orientation response. Hypothyroidism was induced in the pups by feeding the pregnant or lactating female a diet of .2% propylthiouracil from Day 15 of gestation to Day 22 postpartum. Pups receiving replacement therapy and pups made hyperthyroid were injected daily with thyroxine, starting at birth. The ability of the pups to initiate and maintain locomotion toward the nest was assessed between Days 4 and 22. Hyperthyroid, control, and replacement therapy pups behaved very similarly on the task, showing a peak in the percentage of pups homing between Days 12 and 16. Hypothyroid pups showed a delay in the peak percentage until Day 20, although the percentage of pups was similar to that found in other treatments. An integrated behavioral response can be delayed by hypothyroidism and still emerge apparently intact at a later age.
Development of olfactory and thermal responsiveness in hypothyroid and hyperthyroid rat pups
Authors: Johanson Ingrid B.
Published: January 2005

Hypo‐ and hyperthyroid rat pups were tested for their responsiveness on an olfactory and a thermal gradient in an attempt to evaluate the effects of perinatal thyroid manipulation on the ability of the pups to use these cues in orientation. Hypothyroid pups showed a delay and hyperthyroid pups an acceleration in the development of orientation along the olfactory gradient, relative to controls. None of the pups was able to utilize a thermal gradient in directed orientation but pups moved less at the warm end of the gradient than at the cool end. This differential responsiveness was strongest in the hypothyroid pups, suggesting that these pups could utilize thermal cues in an orthokinetic orientation.
Ontogeny of short‐ and long‐term memory capacities for passive avoidance training in undernourished mice
Authors: Nagy Z. Michael , Porada Kenneth J. , Monsour Ann P.
Published: January 2005

To assess the effects of early postnatal undernutrition upon the developing abilities of infant and juvenile mice to acquire and retain a passive‐avoidance response, we reared mice following birth in either “normally nourished” or “undernourished” conditions by maintaining litter sizes of 6 or 16, respectively. At ages ranging from 7 to 21 days of age, mice from each nutritional condition were trained to withhold stepping off from a small vibrating platform in order to avoid shock. Following training to a common criterion, separate groups of mice were retrained to the same criterion either 1 or 24 hr later. From the comparisons with yoked control groups at each age and retention interval, we conclude that although undernutrition results in some age‐related differences in the ability to withhold responding, these are quite small during acquisition within each age group. In contrast, the retention data suggest that undernutrition delayed the development of both short‐ and long‐term memory abilities on this task. In general, these results are similar to earlier data involving discriminated shock‐escape wherein undernutrition had little apparent effect upon acquisition at the early ages but rather marked effects upon developing memory systems.
Relative effects of maternal and pup heredity on postnatal mouse development
Authors: Wainwright Patricia
Published: January 2005

This study was designed to assess the separate effects of inbreeding the mother and the pups on behavioral development in the mouse. The pups were tested on a standardized developmental rating scale at 32 days gestational age. The results indicated that maternal inbreeding retarded development by 1.5 days and that inbreeding the pups retarded development by .7 days.
Interactive effects of nutrition and cannabis upon rat perinatal development
Authors: Charlebois A. T. , Fried P. A.
Published: January 2005

In order to examine the effects of cannabinoids, malnutrition, and their possible interaction upon the developing rat fetus, female Wistar rats were exposed to cannabis smoke, placebo smoke, or no smoke while concurrently consuming 1 of 3 diets differing in protein concentration (8%, 24%, 64%). Both the diet and drug treatments were administered 20 days prior to and throughout gestation. Of the 12 variables affected by the low‐protein diet, 8 were significantly potentiated when undernutrition was combined with cannabis treatment. Some dependent variables that were not altered either by the low‐protein diet or by cannabis inhalation were affected by the combination of treatments. These included a lengthened gestation period, an increase in occurrence of stillbirths and litter destruction, and decreased activity in the rat pups. Cannabis coupled with a standard protein diet resulted in a number of developmental indices being delayed but combining the drug with an enriched protein diet ameliorated these effects. The evidence also suggests that the administration of cannabis both before and during gestation resulted in a degree of tolerance to some aspects of the drug effects.
Circumcision, gender differences, and neonatal behavior: An update
Authors: Brackbill Yvonne , Schroder Kerri
Published: January 2005

As a test of the hypothesis that gender differences in neonatal behavior may be linked to circumcision, we reviewed 38 recent studies which provide relevant information. No strong data exist to support the hypothesis or to document the existence of gender differences in neonatal behavior.
Learning deficits in the neonatal peking duckling produced by decreased oxygen consumption during late prenatal periods: A cautionary note
Authors: Heaton Marieta B. , Klein Steven L.
Published: January 2005

Neonatal Peking ducklings were tested in a detour problem‐solving task following replacement of the shell overlying the air space of the egg on Prenatal Day 24 (total incubation period: 27 days) with a plastic wrap. This procedure, a common practice in behavioral embryology, resulted in a significant decrease in oxygen consumption, and a protracted retardation in the mastery of the learning task, with experimental ducklings solving the problem at a mean age of 5.27 days, compared with 2.32 days for controls. These results serve to underscore the problems that may be encountered as a result of any intereference with the integrity of the egg during the prenatal period.
Recovery from experimentally induced problem‐solving deficits in neonatal peking ducklings as a function of environmental stimulation
Authors: Heaton Marieta B. , Klein Steven L.
Published: January 2005

Neonatal Peking ducklings were reared in 3 different environments containing varied light and sound stimulation. One group was exposed to the stimulative environment only during the last 3 prenatal days, 1 group was placed in the stimulative environment at the time of hatching, and the 3rd group was exposed to the stimulative environment both pre‐ and postnatally. No differences in performance in a detour learning task were noted between controls and experimentals from the 1st 2 groups (prenatal stimulation only and postnatal stimulation only); however, the group receiving both pre‐ and postnatal stimulation solved the detour task significantly faster than their controls. This learning improvement as a function of the stimulative environment represents a partial recovery from the deficit produced as a result of the experimental paradigm in which the shell covering the air space was replaced with clear plastic wrap, a procedure which has been shown to reduce oxygen consumption and lead to learning retardation.
Suckling: Developmental indicator of genetic obesity in mice
Authors: Wilson Linda M. , Chang Shih‐Shung P. , Henning Susan J. , Margules David L.
Published: January 2005

The Bar Harbor obese‐hyperglycemic mouse (ob/ob) characteristically develops its obese phenotype during the postweaning period, when access to food is unrestricted and its behavioral phenotype of hyperphagia appears. In the present study suckling behavior (viz., nipple attachment latencies and total suckling time) of lean and preobese mouse pups, derived from matings of heterozygous lean parents, was measured in either fed or fasted conditions from 6 to 21 days postpartum on anesthetized dams. Twenty‐hour milk deprivation selectively channeled pup activity into suckling for both preobese and lean mice, although, in general, preobese mice nipple‐attached sooner and suckled longer than leans. In particular, fed preobese pups suckled longer than fed lean pups from 18 days on, providing a preweaning behavioral indicant of a genetic tendency to obesity when environmental constraints on overeating are minimized.
Heightened arousal in the 2‐week‐old rat: The importance of starvation
Authors: Moorcroft William H.
Published: January 2005

The 2‐week‐old rat has frequently been reported to be hyperactive; however, the causes of this are disputed. In 3 experiments, with split‐litter designs, the following possibilities were eliminated as causative factors: (a) body temperature; (b) nest seeking; and (c) maturation of peripheral sensory, motor, and endocrine systems. In contrast, the isolated 2‐week‐old rat, in a novel environment, was shown to be very reactive to hunger, however mild. Further, this was true whether the hunger was self‐generated during a forced switch in diet or of external origin due to food deprivation. These data are consistent with and supportive of the hypothesis that the 2‐week‐old rat does not have functionally‐mature forebrain inhibitory structures with which to modulate arousal. Thus, even a mild arousal stimulus results in extreme hyperactivity. Further, these results, together with previously published results, suggest that the concurrence of isolation, starvation, and novelty of environment are necessary, but none of these alone is sufficient, for the 2‐week‐old rat to become hyperactive.
Deficits in spatial memory performance induced by early undernutrition
Authors: Jordan T. C. , Cane S. E. , Howells K. F.
Published: January 2005

Recent studies have shown that rats have a remarkable ability to keep track of their spatial location. Explanations stress the involvement of a form of short‐term (working) memory in which the hippocampus appears to play a major role. The hippocampus appears to be vulnerable to early undernutrition and preliminary investigations indicate that Areas CA3 and CA4 suffer the most. Ninety‐day‐old rats, previously undernourished prenatally and throughout lactation, were tested in an 8‐ and, then, a 16‐arm radial maze. Significant differences were observed between the experimental and control groups on both tests, especially in the 16‐arm maze. Error distributions were also significantly different with experimental animals tending to perseverate in 1 area of the maze. Differences were also observed in the time taken to make the choices and in exploratory behavior. We conclude that early undernutrition affected the spatial learning ability of the animals and that this may be due to the distortions observed in the normal growth pattern of the hippocampus.
Isolation has permanent effects upon the behavior of the rat, but not the mouse, gerbil, or guinea pig
Authors: Einon Dorothy F. , Humphreys Anne P. , Chivers Susan M. , Field Sarah , Naylor Vivian
Published: January 2005

In the rat isolation has both short‐and long‐term influences upon behavior. Rats isolated at any age will show increases in timidity and aggression, but both effects can be reversed by periods of social housing. However, isolation before 50 days of age has permanent effects upon behavior. We have previously found that rats between 25 and 45 days of age may be protected from the deleterious effects of isolation by short daily periods of social contact if, during these daily contact periods, the rats engage in intense bouts of rough‐and‐tumble play. In this study we examined the permanence of the effects of isolation on the rat, mouse, guinea pig and gerbil. As predicted by the play hypothesis, species which do not engage in extensive social play do not show permanent deficits if isolated prior to 50 days. Only rats which engage in long bouts of rough‐and‐tumble play between 20 and 50 days show any permanent behavioral effects of isolation during this period.
Hypothermia‐induced retrograde amnesia in mature and aged rats
Authors: Hamm Robert J.
Published: January 2005

Mature (10‐month‐old) and aged (25‐month‐old) rats were trained on a passive avoidance task. Following training, rats in each age group were exposed to a hypothermia treatment, restraint alone, or no treatment. The hypothermia treatment involved immersing the mature rats in 4°C water for 12 min and immersing the aged rats in 1°C water for 12 min. This treatment reduced the body temperature of both age groups to an equivalent temperature (22°C). Following immersion, the body temperature of the aged rats continued to decline to a lower level and recovered at a slower rate than the mature rat's temperatures. When all rats were tested 24 hr after training for retention of the avoidance task, mature rats performed better than aged rats when trained with the same shock intensity. Increasing the shock duration for the aged rats eliminated the performance differences on the passive avoidance task between ages. Rats exposed to hypothermia showed poorer retention of the task (i.e., retrograde amnesia) than all control conditions. However, no age differences in the degree of amnesia induced by the hypothermia treatment were apparent once age groups were equated on the intensity of the amnesic agent (hypothermia) and degree of initial learning.