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J F DeBold

Publications and source records attributed to J F DeBold.

At least 37 records · Page 2Linked to original sources
PubMed1989

Temporal and sequential patterns of agonistic behavior: effects of alcohol, anxiolytics and psychomotor stimulants.

Social and agonistic interactions are composed of a range of species-typical acts, postures, displays and other communicative signals that follow characteristic patterns. Descriptive and analytic methods permit an assessment of the temporal and sequential features of highly probable patterns of agonistic interactions. Analysis of the intervals that separate consecutive attacks by a resident mouse or rat toward an intruder identifies bursts or epochs of attacks. Amphetamine (1.25, 2.5 mg/kg), but not diazepam or alcohol, alters the burst pattern of attack behavior. Higher doses of alcohol, but not diazepam, in either resident male rats or in lactating rats confronting an intruder, reduce the sequences of aggressive acts and postures with high transition probabilities as identified by lag sequential analysis. These results suggest that temporal and sequential patterning mechanisms may be differentially altered by amphetamine- and alcohol-type substances. These neural for many types of behavior.

Aggression↗
PubMed1989

Facilitation of sexual receptivity by hypothalamic and midbrain implants of progesterone in female hamsters.

In the first experiment, ovariectomized female hamsters were stereotaxically implanted with bilateral guide cannulae aimed at the medial preoptic area (POA), ventromedial hypothalamus (VMH), or ventral tegmentum (VTA). The following week these females were injected SC with 10 micrograms estradiol benzoate (EB) and then had 27-gauge cannulae containing crystalline progesterone inserted through the guide tubes. Sexual receptivity was observed in 3 of 11 animals with VMH implants of progesterone, in 2 of 10 with VTA progesterone, but in none with POA implants. In the second experiment, the amount of intracranial progesterone was increased by mechanically expelling a 1.5 micrograms progesterone pellet from the tip of each cannula insert. This treatment facilitated receptivity in 10 of 20 hamsters with VTA implants and in 9 of 32 VMH-implanted animals. This induction of receptivity required approximately 2 hr. Progesterone pellets in the POA, mammillary region, and lateral mesencephalon were generally ineffective. In hamsters, progesterone into either the VMH or the VTA is sufficient to facilitate receptivity, although neither site is highly sensitive to progesterone. These results differ from those in recent studies in rats and this difference may reflect important species differences in the control of lordosis.

Animals↗
PubMed1988

Site-specific inhibition of receptivity by intracranial anisomycin in hamsters.

The ventromedial nucleus of the hypothalamus (VMH) has been implicated in the mediation of the hormonal control of female rodent sexual behavior. However, in hamsters, progesterone (P) has been found to have effects on sexual receptivity in other diencephalic and mesencephalic sites as well. Progesterone is thought to exert its behavioral effects by altering protein synthesis in CNS target neurons. We tested the effects of 30 gauge implants of the protein synthesis inhibitor anisomycin in the preoptic area (POA), VMH, and ventral mesencephalon (VMES) 30 minutes before 500 micrograms P SC, on the facilitation of lordosis in ovariectomized estrogen-primed female hamsters. The same animals were tested one week later with estrogen and progesterone treatment but without anisomycin. Anisomycin reduced sexual receptivity (lordosis) when placed in the VMH or VMES, but not when delivered to the POA. The results confirm the importance of the VMH in the mediation of progesterone facilitation of female sexual behavior, but also provide evidence that ventral midbrain structures may play a role in female sexual receptivity in hamsters. These two structures may be important for different aspects of lordosis. Progesterone effects in both sites appear to be protein synthesis dependent.

Animals↗
PubMed1985

Testosterone modulates the effects of ethanol on male mouse aggression.

In a series of three experiments, we evaluated the degree to which the effects of acutely administered ethanol on aggressive behavior of male CFW mice toward a male intruder interact with, and depend on, androgen levels. In the first experiment, mice were tested at 15 min after 0, 0.1, 0.3, 1.0, 1.7, or 3.0 g/kg of ethanol PO. The highest dose (3.0 g/kg) significantly suppressed aggression by the male residents. In the second experiment, aggressive behavior was suppressed from 5 to 60 min after 3.0 g/kg ethanol administration PO. The third experiment evaluated the role of testosterone in these effects in another set of male mice that were castrated and then implanted with a 7.5-mm or 2.5-mm silastic capsule of testosterone (T) or a silastic capsule containing cholesterol as a control. The castrated mice with 2.5-mm T capsules or cholesterol capsules had lower baseline levels of aggression than intact mice or castrated males with 7.5-mm T capsules, but they demonstrated an alcohol dose-response pattern similar to that of the intact males. The castrated males with 7.5-mm T capsules had a different dose-response curve than the other males. Doses of 1.0 and 1.7 g/kg ethanol PO significantly enhanced aggression; 5.6 g/kg was required to suppress aggression. Ethanol effects on aggressive behavior did not require T or changes in T level, but T levels altered behavioral sensitivity to ethanol.

Aggression↗
PubMed1984

Aggression persists after ovariectomy in female rats.

Aggression occurs not only in males but also in females, however, under different sex-specific stimulus and endocrine conditions. After being housed with males, female rats exhibit frequent and intense aggressive behavior toward unfamiliar rats. However, the female residents primarily attack female intruder rats, while the male residents attack males and not females. Altering the hormonal condition of the intruders can modify the behavior that they provoke from the residents. Castration of the male intruders reduces aggression from male residents, but ovariectomy of the female intruders does not alter the behavior of the female residents. Treatment of the gonadectomized intruders with gonadal steroids significantly alters the response of the male residents. Resident-intruder aggressive behavior depends on the presence of the testes in the male residents but not on the ovaries or on lactation in the female residents. Even 7 weeks after ovariectomy the female residents continue to show aggressive behavior toward female intruders. In the same time period the castrated male residents show a marked decrease in aggressive and sexual behavior.

Aggression↗
PubMed1984

The relative effectiveness of progestins for facilitation and inhibition of sexual receptivity in hamsters.

In a series of experiments, we studied the biphasic actions of 4 progestins on sexual receptivity in female hamsters. Based on previous reports, we selected doses of progesterone (P), desoxycorticosterone acetate (DOCA), 5-alpha-dihydroprogesterone (DHP) and 20-alpha-hydroxyprogesterone (20-OHP) that were expected to have initial facilitative and/or subsequent inhibitory actions on sexual receptivity. Estrogen-primed ovariectomized female hamsters were given one of 4 doses of a progestin at hour 44 post EB, and were tested for facilitation (with tape over their vaginas to prevent intromissions) 4 hours later. At hour 68, all animals received 500 micrograms P and were tested for the inhibitory effects of the test progestin 4 hours later. In additional experiments, similar procedures were followed with an alternate vehicle (1% Tween-80 instead of sesame oil) and a longer initial progestin-to-facilitation test interval (8 rather than 4 hours) in attempts to improve bioavailability of the steroids. P and DOCA were clearly the most behaviorally effective progestins tested, and they were equally potent for facilitation and inhibition in an oil vehicle at the 4 hour interval. DHP given in oil caused some inhibition but no facilitation. 20-OHP had no behavioral effects at the doses tested. The results are discussed in light of previous results with these steroids in hamsters and other rodent species. Also, the differing patterns of effectiveness across conditions provide some, although qualified, support for our view that the biphasic actions of progestins may be controlled by separate mechanisms. However, an alternate explanation is also discussed.

20-alpha-Dihydroprogesterone↗
PubMed1984

Heightened aggressive behavior by animals interacting with alcohol-treated conspecifics: studies with mice, rats and squirrel monkeys.

Drug-free mice, rats and squirrel monkeys showed more aggression toward alcohol-treated conspecifics than under control conditions. Quantitative ethological analysis was used to assess the dose-dependent effects of ethyl alcohol on a range of aggressive, submissive, defensive, escape responses as well as on non-agonistic behavior such as associative responses, grooming, and locomotor activities. Two experimental situations were studied: resident-intruder confrontations in mice and rats, and interactions between members of established groups of squirrel monkeys. After PO administration of ethyl alcohol to intruder mice and rats, the non-drugged resident mice and rats attacked, threatened, and pursued intruders at higher frequencies during 5-min encounters. Similarly, subordinate squirrel monkeys who were members of three established groups, when given alcohol, were grasped, displaced, and displayed to more frequently by non-drugged group members than after water control injections during the first 40 min after injection. This change in aggressive behavior by non-drugged animals was related to the alcohol dose given to the intruder or subordinate animal; near-ataxic alcohol doses (3.0 g/kg in mice, 1.7 g/kg in rats, 1.0 g/kg in squirrel monkeys) altered the behavior of animals whose prevalent pattern is defensive and submissive so that they were the subject of most frequent and intense aggression.

Aggression↗
PubMed1983

Androgen and estrogen receptors in adult hamster brain.

Both androgen and estrogen receptors are present in the hypothalamus-preoptic area and remaining "brain' regions of gonadectomized adult male and female hamsters. No quantitative or qualitative sex differences are detectable in either receptor system. According to all biochemical criteria tested, both receptors are qualitatively similar to those present in mouse and rat brain. However, there are striking species differences in both the relative concentration and distribution of both androgen and estrogen receptors in hamster brain compared to mouse and rat brain.

Animals↗
PubMed1983

Inhibition of sexual receptivity after intracranial cycloheximide infusions in female hamsters.

Female hamsters were ovariectomized and one week later stereotaxically infused with 20 micrograms cycloheximide (20 micrograms/microliter, 0.6 microliter/min) or 1 microliter saline bilaterally into one of several brain sites. Thirty min after the infusion, the animals were injected with 5 micrograms estradiol benzoate (EB) then 44 hr later with 500 micrograms progesterone and tested with a male for receptivity at hour 48. One week later the animals were retested with EB and progesterone but without any intracranial infusion to investigate the possibility of permanent lesion effects. The greatest inhibition of receptivity occurred in females which received cycloheximide in the ventromedial hypothalamus (VMH) or lateral to the VMH. Saline infusions into the VMH had no inhibitory effects. Inhibition was rarely seen after infusion into the preoptic area, anterior hypothalamus, dorsomedial hypothalamus, cortico-medial amygdala, or septal area. Moderate inhibition was found after infusion of cycloheximide into the third ventricle. The inhibition following cycloheximide infusion was not permanent or irreversible. On the retest one week later the animals were sexually receptive. These results suggest that protein synthesis within the VMH is an essential part of the initial action of estrogen for the induction of sexual receptivity in hamsters.

Amygdala↗
PubMed1982

Sexual receptivity: brain sites of estrogen action in female hamsters.

In order to investigate the brain sites of estrogen action, ovariectomized hamsters were stereotaxically implanted with unilateral 27 gauge cannulae containing estradiol. Groups of females received implants into either the lateral septum, bed nucleus of the stria terminalis, preoptic area, anterior hypothalamus, ventromedial hypothalamus, arcuate nucleus, corticomedial amygdala or mesencephalic central gray. Another set of animals received implants containing cholesterol. One week later the animals were injected with progesterone and 4-5 hours later tested for sexual receptivity. The most receptivity and the most consistent response was seen in females with estradiol implants in the ventromedial hypothalamus. Only a few scattered animals in the other anatomical groups showed any receptivity. Only in animals with implants in the anterior hypothalamus was there any evidence of leakage of estrogen into peripheral circulation as measured by uterine weight. There was no response in females with cholesterol implants. Our results suggest that the ventromedial hypothalamus is the most sensitive brain area for the estrogenic induction of female sexual receptivity in hamsters.

Amygdala↗
PubMed1981

Sexual dimorphism in the hormonal control of aggressive behavior of rats.

Male and female rats housed together in small groups both became aggressive toward strange rats placed into their cages. However, male rats mainly attack male intruders and female rats mainly attack female intruders. The hormonal requirements for this aggression are also sexually dimorphic. Castration of the male residents causes a decrease in aggressive behavior, but ovariectomy of the female residents has little effect on their aggression. Replacement therapy to castrated males with 500 microgram/day of testosterone propionate (TP) restores all components of aggressive behavior within 2-3 weeks. Replacement therapy with 5 microgram/day of estradiol benzoate for 3 weeks had no effect on castrated males' aggressive behavior, nor did it cause the males to start attacking female intruders. Replacement therapy to ovariectomized females had a quite different effect. Treatment with EB or EB and progesterone reduced or blocked attack toward intruder females but did not alter the low level of attack toward males. Treatment with TP for 3 weeks also slightly reduced attack toward female intruders but increased the probability of attack toward male intruders. The sex-specificity of aggression and the differential influence of hormones suggests that different mechanisms may be responsible for aggression in males and in females.

Aggression↗