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J B Thurmond

Publications and source records attributed to J B Thurmond.

At least 19 recordsLinked to original sources
PubMed1993

Preattentive and cognitive effects on perceptual completion at the blind spot.

Our findings indicate that preattentive processes, such as the filling in of homogeneously colored areas, discrete dots, or bars across the blind spot, take into account both the color and the form that stimulate the retina around the optic disk. Perceptual completion of the "junction" of two opposite colors facing each other on opposite sides of the blind spot was resolved by simultaneous segregation of the two colors at the location of a filled-in perpendicular line that suggested a boundary separating the two colors. Orientation preference and relative salience of one color versus the other determined which color was perceptually completed in a forced-choice situation that involved perceptual completion at the intersection of a cross formed by bars of opposite colors. A 1-min exposure to these stimuli presented an ambiguous situation for perceptual completion of either color within the blind spot, and resulted in a perceptual "flip-flop" from one color to the other, much like the phenomenon that occurs in figure reversal. Instructions to speed up this reversal process led to a fivefold reduction in latency to first reversal.

Adult↗
PubMed1990

Effects of dietary tyrosine on L-dopa- and amphetamine-induced changes in locomotor activity and neurochemistry in mice.

Recent findings suggest that intraperitoneal injections of L-tyrosine at high doses (100 mg/kg) alters amphetamine-induced changes in behavior by restoring amphetamine-induced decreases in whole brain norepinephrine (NE). The present study examined the motor effects of L-dihydroxyphenylalanine (L-dopa) and d-amphetamine sulfate in mice after treatment with a basal casein diet supplemented with L-tyrosine. The basal diet supplemented with 1-4% L-tyrosine, or 1-4% L-phenylalanine, produced no changes in motor activity in otherwise untreated mice. Whereas L-dopa (25-100 mg/kg) following inhibition of extracerebral decarboxylase by Ro 4-4602 (25 mg/kg) slightly decreased activity in diet control (casein) animals, this drug treatment enhanced motor activity in a dose-related fashion when L-tyrosine was added to the diet. Increases in motor activity following low doses of amphetamine (0.75-1.5 mg/kg) in casein control mice were antagonized by dietary L-tyrosine, but a higher dose of d-amphetamine (3 mg/kg) interacted with the addition of L-tyrosine producing an increase in motor activity. Neurochemical changes observed in brain concentrations of tyrosine, dopamine (DA), norepinephrine (NE), dihydroxyphenylacetic acid (DOPAC), homovanillic acid (HVA), tryptophan, serotonin (5-HT) and 5-hydroxy-indoleacetic acid (5-HIAA) following drug and diet treatments suggest that 5-HT systems, in addition to catecholamine systems, may be involved in mediating these effects.

Animals↗
PubMed1986

Biochemical and behavioral correlates of chronic stress: effects of tricyclic antidepressants.

Using a chronic stress model of depression, the biochemical, hormonal, and neurochemical effects of chronic stress were determined in male CD-1 mice. The effects of chronic administration of three tricyclic antidepressants (TCA): chlorimipramine, amitriptyline and desmethylimipramine, as well as fluoxetine, a specific serotonin uptake inhibitor, were also evaluated. Exposure to acute noise/light stress dramatically increased motor activity (behavioral activation) in comparison with basal (unstressed) activity. However, animals with a history of chronic stress exhibited reduced basal activity levels as well as a decreased behavioral activation response to acute stress. There was also exaggerated corticosterone (CS) responding in both of these behavioral test situations attributable to prior chronic stress exposure. Chronic treatment with any of the TCAs significantly restored the behavioral activation response to acute stress and normalized CS responding in chronically stressed animals. Chronic fluoxetine treatment was ineffective. In chronically stressed, but behaviorally untested (quiescent) mice, there were no changes in CS levels, but norepinephrine (NE) and 5-hydroxyindoleacetic acid (5-HIAA) levels were increased. However, chronically stressed mice tested for basal motor activity showed large NE decreases, while those receiving acute stress exposure prior to testing showed large NE decreases and further 5-HIAA increases. There were no alterations on neurochemical parameters due to any drug treatment which could be correlated with a possible mechanism for their efficacy, although evidence suggested NE involvement. It was further proposed that the chronic stress paradigm induced conditioned neuroendocrine and neurochemical responses.

Animals↗
PubMed1986

Monoamines and effects of chlordiazepoxide on the corticosterone response to stress.

Administration of chlordiazepoxide (CDP) (5 mg/kg) decreased plasma corticosterone (CS) levels of mice exposed to noise stress and increased CS levels in nonstressed mice (20 and 40 mg/kg). The increase in CS may be related to an observed decrease in locomotor activity. Quipazine (0.5 mg/kg), a serotonergic agonist, failed to alter CS levels in animals without prior drug treatment and attenuated the rise in CS of nonstressed mice. These results contradicted a possible serotonergic facilitatory effect on CS regulation. Administration of apomorphine (0.5 mg/kg) or clonidine (0.1 mg/kg) prevented the significant reduction of CS levels in stressed mice treated with low doses of CDP. Apomorphine, alone, increased CS of nonstressed mice to levels approximating those of vehicle-treated stressed mice. Thus, a norepinephrine inhibitory effect was not evident and possible dopaminergic involvement in CS response regulation was suggested. It seemed likely that the effect of CDP on the hypothalamic-pituitary-adrenal system was dependent upon the endocrine state of the animal. Mice exposed to stress and exhibiting higher levels of CS were affected differently by CDP treatment than their nonstressed counterparts.

Animals↗
PubMed1985

Maternal aggression in mice: effects of treatments with PCPA, 5-HTP and 5-HT receptor antagonists.

Drug treatments which influence brain serotonergic systems were administered to lactating female mice during the early postpartum period, and their effects on aggressive behavior, locomotor activity and brain monoamines were examined. P-chlorophenylalanine (200 and 400 mg/kg) and 5-hydroxytryptophan (100 mg/kg) inhibited fighting behavior of postpartum mice toward unfamiliar male intruder mice. These drug-treated postpartum females showed increased latencies to attack male intruders and also reduced frequencies of attack. In addition, postpartum mice treated with the serotonin receptor antagonists, mianserin (2 and 4 mg/kg), methysergide (4 mg/kg) and methiothepin (0.25 and 0.5 mg/kg), displayed significantly less aggressive behavior than control mice, as measured by reduced number of attacks. Whole brain monoamine and monoamine metabolite levels were measured after drug treatments. The behavioral results are discussed in terms of drug-induced changes in brain chemistry and indicate a possible role for serotonin in the mediation of maternal aggressive behavior of mice.

5-Hydroxytryptophan↗
PubMed1985

Interaction of dietary tryptophan and social isolation on territorial aggression, motor activity, and neurochemistry in mice.

This study examined the interaction of dietary tryptophan (TRP) and differential housing on territorial-induced aggression, locomotor activity, and monoamine neurochemistry in mice. Groups of male CF-1 mice were singly-housed or group-housed and administered a semisynthetic basal diet supplemented with TRP (0.25-1.0%). Behavioral measures were taken at various intervals up to 2 weeks after dietary administration was instituted. Separate groups of mice were given the same experimental treatment and sacrificed for whole brain determination of the monoamines and their metabolites. Isolated mice were consistently more aggressive than grouped animals, suggesting that territorial-induced aggression is synergistic with intermale aggression based on social isolation. The combination of isolation and 0.50% TRP was particularly effective in producing increases in aggression that reached maximal levels after 10 days of diet administration. However, motor activity of singly-housed mice was unaffected by TRP, while that of grouped mice was decreased after 5 days of 0.50% TRP. By day 14 of administration behavioral changes tended to return to baseline levels. Neurochemical measures indicated increased DA and 5-HT turnover in isolated mice, with the 5-HT system most affected by dietary TRP. Because housing conditions were a prominent factor in the aggression and neurochemistry, the results suggest the involvement of both transmitter systems in this behavior. However, there were no changes in monoamine turnover that could account for the development of behavioral tolerance.

Aggression↗
PubMed1985

Brain amines and effects of chlordiazepoxide on motor activity in response to stress.

The effect of chlordiazepoxide (CDP) on emotional responsiveness to stress was determined in CD-1 male mice. The relationship of the monoamines to the mediation of emotional behavior was examined with drugs having selective actions on serotonin (5-HT), norepinephrine (NE), and dopamine (DA). Emotional behavior as measured by locomotor activity was increased by stress. This activation enhanced the stimulatory effect of low doses of CDP (5 and 10 mg/kg) and attenuated the depressant action of higher doses (20 and 40 mg/kg). Quipazine (0.5 mg/kg) reduced the depressant effect of CDP in stressed animals. Its action failed to support a proposed anti-serotonergic action of CDP and implicated possible dopaminergic involvement. In stressed mice, apomorphine (0.5 mg/kg) and clonidine (0.1 mg/kg) antagonized the stimulatory action of low doses of CDP. Behavioral effects of clonidine provide support for the notion that the stimulatory effects of CDP may be due to enhanced catecholamine (CA) neurotransmission. Whole brain levels of NE and DA were significantly increased when clonidine was combined with CDP. This indicated a possible reduction in CA turnover and activity.

Animals↗
PubMed1984

Effect of brain monoamine precursors on stress-induced behavioral and neurochemical changes in aged mice.

Male CF-1 mice aged 22 months showed approximately the same level of motor activity and aggressive behavior as 3-month-old mice under control (no stress) conditions, or 45 min following cold swim stress. Increasing brain catecholamine activity by dietary L-tyrosine treatment had no effect on these two age groups either under control conditions or after stress. In contrast, 30-month-old mice showed lower motor activity under control conditions which was raised significantly by supplementation of the diet with L-tyrosine. However, marked reductions in activity and aggression following stress were observed in the 30-month-old animals and these deficits were not reversed by L-tyrosine treatment prior to stress. Reduction in motor activity was greatest in stressed, 30-month-old mice on L-tyrosine supplemented diets. Compared to 3-month-old mice, the 30-month-old animals had lower brain tyrosine following dietary L-tyrosine treatment, lower brain tryptophan, norepinephrine (NE), dopamine (DA) and DOPAC, but higher HVA, serotonin (5-HT) and 5-HIAA levels. Under both control (no stress) and stress conditions, L-tyrosine pretreatment decreased brain 5-HT in the young animals, but increased 5-HT in the old mice. After stress the 30-month-old animals evidenced only slight increases in levels of blood corticosterone. Brain tyrosine was reduced by stress in the young animals but increased by stress in the old animals. Stress-induced decreases in brain NE and increases in serotonin and 5-HIAA levels were observed in both age groups. These results are consistent with hypotheses concerning age-related alterations in brain monoamine functions and adrenocortical control mechanisms.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Effects of drug-induced changes in brain monoamines on aggression and motor behavior in mice.

Mice maintained on a basal casein diet supplemented with 4% L-tyrosine potentiated L-DOPA effects on aggression. At low doses (12.5-25 mg/kg) L-DOPA increased aggression whereas at high doses (50-100 mg/kg) it decreased aggression. 5-HTP (50-200 mg/kg) produced a dose-dependent decrease in aggression and motor activity which was antagonized by pretreatment with dietary L-tyrosine (4%) or L-DOPA (50 mg/kg). L-DOPA induced reductions in motor activity were, in turn, antagonized by 5-HTP. Increases in motor activity following d-amphetamine (3 mg/kg) were sharply reduced by 5-HTP (50-100 mg/kg), but 5-HTP potentiated reductions in aggression following d-amphetamine. The concentration in brain of tyrosine, DOPA, dopamine (DA), noradrenaline (NA), DOPAC, HVA, tryptophan, serotonin (5-HT), and 5-HIAA were obtained following drug and diet treatments. The changes observed, particularly in DA and 5-HT metabolites, provide further evidence for an inhibitory role of brain 5-HT systems in the mediation of the behavioral effects of d-amphetamine and the catecholamine precursors, L-tyrosine and L-DOPA.

3,4-Dihydroxyphenylacetic Acid↗
PubMed1984

Effect of catecholamine precursors on stress-induced changes in motor activity, exploration, and brain monoamines in young and aged mice.

Male CF-1 mice aged 24 months showed the same level of motor activity and exploratory behavior as 3-month-old mice under control (no stress) conditions or 45 min following cold-swim stress. Within 90 min after stress exposure, motor activity level in both age-groups returned to control values. In contrast, 30-month-old mice showed lower motor activity under control conditions and marked reductions in activity and exploration following stress which recovered to only half of the control value 90 min after stress. These deficits in the 30-month-old animals were not reversed by L-tyrosine or L-dopa treatment prior to stress. L-Tyrosine supplement did not affect any of the behavioral measures despite having pronounced effects on brain tyrosine levels. Compared with 3-month-old mice, the 30-month-old animals had lower brain tyrosine following dietary L-tyrosine treatment, lower norepinephrine (NE), dopamine, and dihydroxyphenylacetic acid, but higher homovanillic acid levels, and after stress evidenced only slight increases in levels of blood corticosterone. Stress-induced decreases in brain NE and increases in serotonin and 5-hydroxyindoleacetic acid levels were observed in both age-groups. Data are discussed in terms of age-related alterations in brain monoamine functions and adrenocortical control mechanisms.

Aging↗
PubMed1982

Effect of fusaric acid on aggression, motor activity, and brain monoamines in mice.

The effects of fusaric acid (FA), a dopamine-beta-hydroxylase (D beta H) inhibitor, were determined on aggression, motor activity, and brain monoamines at doses of 3.2 to 60 mg/kg following administration of dietary supplements of L-tyrosine or balanced protein to male albino mice. Compared to saline injected control animals, both aggression and motor activity were reduced by the highest doses of FA. Somewhat more reduction in aggression was observed in animals administered dietary supplements of casein compared to those given the tyrosine supplement. Treatment with FA at doses of 30 to 60 mg/kg decreased brain norepinephrine and dopamine, and decreased brain tyrosine in animals fed the tyrosine supplement. In contrast, FA increased 5-hydroxytryptamine, and caused marked increases in 5-hydroxyindoleacetic acid at the highest doses. The data suggest that the neurochemical effects of FA may not be the same in rats and mice.

Aggression↗
PubMed1979

Differential tolerance to dietary amino acid-induced changes in aggressive behavior and locomotor activity in mice.

Male albino mice were maintained on a semisynthetic 12% casein protein diet for 2 weeks, then switched to diets modified by the addition of a 4% L-amino acid supplement (L-tyrosine, L-phenylalanine, and L-tryptophan) or 4% casein (control). Territorial=induced aggressive behavior increased following 1 week on the amino acid supplements, especially after tyrosine, but an apparent tolerance developed to these effects after 5 weeks on the amino acid supplements. Locomotor activity also increased following 1 week on the supplements, most notably after phenylalanine alone or in combination with tyrosine, and these effects tended to persist after 5 weeks on the supplements. Endogenous whole brain levels of dopamine, norepinephrine, serotonin, 5-hydroxyindoleacetic acid, tyrosine, phenylalanine, and tryptophan showed no tolerance to increased concentrations of brain catecholamines and indoleamines over the 5-week period, and no clear relation between the concentrations of these monoamines and the behavioral changes.

Aggression↗
PubMed1977

Effects of dietary tyrosine, phenylalanine, and tryptophan on aggression in mice.

Dietary amino acid regimens designed to enhance catecholaminergic and serotonergic functioning were found to differentially affect territorial-induced attacks in mice. Male albino mice were maintained on a semi-synthetic 12% casein protein diet for 2 weeks, then switched to diets modified by the addition of a 4% L-amino acid supplement, or 4% casein (control). Measures of aggressive behavior and open-field locomotor activity were obtained before and after the dietary supplements were administered. Resident mice fed supplements of L-tyrosine displayed a marked increase in the number of attacks on intruders and shorter attack latencies, but their locomotor activity was unaffected. L-phenylalanine supplements alone or in combination with L-tyrosine reduced the latency to attack and increased motility but did not affect the number of attacks. As a whole, the group of animals fed L-tryptophan showed no changes in aggression or motility.

Aggression↗
PubMed1975

Technique for producing and measuring territorial aggression using laboratory mice.

A method was developed for producing and measuring territorial aggression in male CF-1 laboratory mice using a simple apparatus. The technique is based on data collected from approximately 1000 CF-1 mice in order to establish the parameters and optimize the procedures. In this technique the mouse takes up lone residence for 24 hr in a 60 cm square box attached by a tubular runway to a standard mouse (home) cage with food, water, and bedding. After this interval, a naive intruder male CF-1 mouse of the same age is introduced. Under control (no treatment) conditions, 85-90 percent of the resident mice will attack the intruder with a latency of about 5 min and all residents attacking the intruder are dominant. Dominance or submission is typically decided within the first 20 min of the test. Data on 10 pairs of mice can be collected simultaneously by one observer. Treatments can be assessed in terms of their effects on the production of aggression (percentage of animals attacking) in either the resident or the intruder, and on the level of aggression produced by recording the latency to attack, the frequency of attacks, and the number of animals wounded (showing blood) during the 20 min observation period. The advantages of the technique include the use of a naturally occurring aggressive behavior (as opposed to techniques empolying long periods of isolation, shock, or drugs), the highly reliable occurrence of aggression, the ability to study animals exposed to either aggression or defeat, the clear and valid measures of aggression produced, the simple and sturdy apparatus, and the convenience and economy of data collection.

Aggression↗