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PubMed1994

Effects of chemical and visual exposure to adults on growth, hormones, and behavior of juvenile green iguanas.

For 1 year, groups of juvenile male green iguanas (Iguana iguana) were housed such that one group was visually exposed to an adult female, a second group was both visually and chemically exposed to an adult female, a third group was visually exposed to an adult male, and a fourth group was both visually and chemically exposed to an adult male. Juvenile males exposed to signals from adult males showed signs of chronic stress, including reduced growth rates, lower testosterone levels, higher corticosterone levels, and decreased frequencies of headbob display. Although visual exposure alone was sufficient to suppress growth, testosterone levels, and rates of display, the addition of chemical exposure strengthened some of these effects. Both chemical and visual exposure to an adult male were necessary to produce elevated corticosterone levels. In contrast, juvenile males exposed to visual and chemical signals from an adult female exhibited growth rates, hormone levels, and behavior patterns typical of juvenile males housed in the absence of adults of either sex. These results suggest that visual and chemical signals from dominants may serve to reinforce social relationships among males through their influence on the physiology and behavior of receivers.

Agonistic Behavior↗
PubMed2006

Does extra corticosterone elicit increased begging and submissiveness in subordinate booby (Sula nebouxii) chicks?

We tested whether in two-chick broods of the blue-footed booby (Sula nebouxii) elevated circulating corticosterone in the socially subordinate broodmate facilitates submissive behavior and/or enhances food solicitation. Implanting corticosterone in 17 subordinate chicks (experimental broods) produced changes in the behavior of chicks and parents over the first two days, relative to 17 matched families (control broods) where subordinate chicks were implanted with empty capsules. Experimental broods showed increased activity/wakefulness of the dominant broodmate and, consequently, increased simultaneous activity of both broodmates, but there was scant evidence that subordinates submitted more readily when attacked. Implanted subordinates increased their rate of spontaneous submission over the total observation time, but this increase was mostly explained by the additional time when both broodmates were simultaneously active. There was little sign that extra corticosterone induced more begging, except possibly by eliciting increased activity. Experimental broods increased their rate of feeding, and most if not all of the increase was due to the increased activity and increased feeding rate of dominant broodmates. On the third and fourth days after implantation all effects of implanted corticosterone disappeared, except for the elevated activity and feeding rates of dominant chicks. At the end of four days, subordinates implanted with corticosterone showed no increase in circulating corticosterone and experimental broods showed no gain in mass or body size, relative to controls. Extra corticosterone, above the high level that normally circulates in subordinate chicks, apparently does not enhance submission to aggression or food solicitation, but provokes a cascade of changes in the behavior of broodmates and parents.

Agonistic Behavior↗
PubMed1989

Role incongruence and gender variation in the provision of prison mental health services.

Correctional administrators are equipped with a variety of responses to manage problematic inmate behavior. The forms of these responses range from subtle coercion in the context of everyday prison life to segregative placements that include protective custody, disciplinary confinement, and mental health residential services. Using logistic regression, the present study examines the disproportionate placement of female inmates in mental health facilities. The results suggest that placement differences for male and for female inmates reflect both psychiatric need and differential responses to role-incongruent behavior.

Adult↗
PubMed1996

Sigma 1 receptor subtype is involved in the relief of behavioral despair in the mouse forced swimming test.

The immobility time in the mouse forced swimming test was dose-dependently reduced by sigma 1 receptor agonists, such as 1-(3,4-dimethoxyphenethyl)-4-(3-phenylpropyl)piperazine dihydrochloride (SA4503) and (+)-pentazocine, and non-specific sigma receptor agonists, such as 1,3-di(2-tolyl)guanidine (DTG) and (+)-N-cyclopropyl-methyl-N-methyl-1,4-diphenyl-1-yl-but-3-en-1-ylamin e hydrochloride (JO-1784). On the other hand, pre-treatment with N,N-dipropyl-2-[4-methoxy-3-(2-phenylethoxy)phenyl]ethylamine monohydrochloride (NE-100), a putative sigma 1 receptor antagonist, completely antagonized the SA4503-, (+)-pentazocine- and DTG-induced reductions in immobility time. Such phenomena indicate that sigma receptor agonists alleviate behavioral despair. In addition, these antidepressive effects involve mainly the sigma 1 receptor subtype.

Animals↗
PubMed1992

Dopaminergic influences on male sexual behavior of rhesus monkeys: effects of dopamine agonists.

Previous research has demonstrated that the mixed D1/D2 dopamine receptor agonist, apomorphine, and the specific D2 dopamine receptor agonist, quinelorane, facilitated penile erections and masturbatory behavior of male rhesus monkeys when they were tested in the presence of a female monkey that they could see, hear, and smell but not physically contact. The present study was designed to further examine dopaminergic influences on male sexual behavior of rhesus monkeys by evaluating male copulatory behavior following administration of these dopaminergic agents, as well as a D1 agonist, CY 208-243. Apomorphine and quinelorane treatment produced dose-dependent effects on male sexual responding. Compared to vehicle-based performance, postejaculatory intervals were shortened following treatment with either 100-200 micrograms/kg apomorphine or 2.5-10 micrograms/kg quinelorane. Higher doses of apomorphine or quinelorane did not reliably influence the postejaculatory interval. Ejaculation latency, intromission frequency, and number of thrusts/intromission increased following administration of 200-400 micrograms/kg apomorphine and 25 micrograms/kg quinelorane, indicating that dopaminergic stimulation in this dose range raised the monkeys' ejaculatory threshold. No behavioral effects of the D1 agonist, CY 208-243, were observed in this testing situation. These experiments provide further evidence that dopaminergic mechanisms may play a role in the regulation of male sexual behavior of rhesus monkeys and, in particular, demonstrate that the direction of the effect depends on the dopamine receptor subtype and dosage of the dopamine agonist being administered.

Animals↗
PubMed1992

Behavioral characterization of the new potent nonselective dopamine agonist pergolide.

Pergolide (LY127809, CAS 66104-23-2), a non-selective dopamine agonist, was evaluated for broad behavioral properties in a wide range of pharmacological tests. The selective dopamine2(D2) agonist, bromocriptine, served as a reference standard for those tests where behavioral activity was noted with pergolide. Pergolide and bromocriptine were administered orally to mice at doses of 0.3-30 and 3-300 mg/kg, respectively. Both compounds produced biphasic effects on spontaneous activity, increased hexobarbital-induced sleep time, and lowered mouse body temperature. Qualitative changes with pergolide were observed with some mice showing hyporeactiveness, ptosis, slowed respiration and placing loss. Reserpine-induced hypothermia was reversed by pergolide with significant increases in the body temperature of reserpine-treated mice. However, a further reduction in the body temperature of reserpinized hypothermic mice was seen following bromocriptine administration. Acetic acid-induced writhing and performance on the rotarod were both impaired by higher doses of pergolide. Bromocriptine administration also reduced writhing at higher doses but did not alter performance on the rotarod. Pergolide had no effect on seizure activity as evaluated by electroshock, pentylenetetrazol (pentetrazol) or strychnine. Oxotremorine-induced tremors and salivation, grip strength, and tail-flick were not affected by pergolide. Neither pergolide nor bromocriptine altered established shuttle-avoidance behavior in rats at oral doses of 0.1 to 30 mg/kg. Behavioral assessment of pergolide in dogs was complicated by severe emetic responses at clinically relevant doses greater than 0.003 mg/kg. In summary, these data suggest that pergolide produces a behavioral profile which is characteristic of dopaminergics.(ABSTRACT TRUNCATED AT 250 WORDS)

Analgesics↗
PubMed2007

Gonadotropin-releasing hormone agonists reduce the migratory and the invasive behavior of androgen-independent prostate cancer cells by interfering with the activity of IGF-I.

Androgen-independent prostate carcinoma is characterized by a high proliferation rate and by a strong metastatic behavior. We have previously shown that GnRH agonists exert a direct and specific inhibitory action on the proliferation of androgen-independent prostate cancer cells (DU 145). These compounds mainly act by interfering with the mitogenic activity of growth factors, such as the insulin-like growth factor-I (IGF-I). The present experiments were performed to clarify whether GnRH agonists might also affect the migratory and the invasive behavior of androgen-independent prostate cancer cells and to define their mechanism of action. First we showed that the GnRH agonist Leuprolide reduces the migration of DU 145 cells towards a chemoattractant and their ability to invade a reconstituted basement membrane. Experiments were then performed to clarify whether the GnRH agonist might act by interfering with the pro-metastatic activity of IGF-I. We found that, in androgen-independent prostate cancer cells, Leuprolide: a) interferes with the IGF-I system (receptor protein expression and tyrosine-phosphorylation); b) abrogates the IGF-I-induced phosphorylation of Akt (a kinase previously shown by us to mediate the pro-metastatic activity of IGF-I in prostate cancer cells); c) counteracts the migration and the invasive activity of the cells stimulated by IGF-I; d) abolishes the effects of IGF-I on cell morphology, on actin cytoskeleton organization and on alphavbeta3 integrin expression/cellular localization. These data indicate that GnRH agonists, in addition to their well known antiproliferative effect, can also exert a significant inhibitory activity on the migratory and invasive behavior of androgen-independent prostate cancer cells, expressing the GnRH receptor. GnRH agonists act by interfering with the pro-metastatic activity of the growth factor IGF-I.

Androgens↗
PubMed1995

Intermale aggression tested in two procedures, using four inbred strains of mice and their reciprocal congenics: Y chromosomal implications.

Indications of a role for the nonpseudoautosomal region of the Y chromosome (YNPAR) in intermale attack behavior have been demonstrated by Maxson's group using C57BL/10 (B10) and DBA/1 (D1) inbred mouse strains and their reciprocal congenics. Carlier and Roubertoux' group, using CBA/H (H) and NZB/B1NJ (N) mice, did not find such a YNPAR effect. For the two research groups, however, not only were the parental strains different, but also the rearing conditions and testing methods. The divergent conclusions drawn may therefore have been due either to genetic variation or to environment-related variables. We carried out two experiments to investigate these alternatives. The N and H strains were raised and tested according to the experimental design used by Maxson's group (homogeneous set test) and the D1 and B10 strains were raised and tested according to the experimental design of Carlier and Roubertoux' group (standard opponent test). Considering all studies together, the YNPAR effect appeared in both sets of mice only when using the homogeneous set test. This raises the question of what environmentally related variables are involved in the YNPAR effect on intermale attack. One strong hypothesis is that the different types of opponents in each experimental design send differing olfactory signals, which, in turn, differentially affect the capacity to elicit intermale attack behavior.

Aggression↗
PubMed1982

Striatal lesions change the behavioral effects of morphine in cats.

Cats injected with a relatively low single dose of morphine sulfate (0.5-3.0 mg/kg i.p.) exhibit a long-lasting group of behaviors which we quantified via a time-sampling video technique. The dominant events are complex head movements accompanied by discrete paw, ear and body movements with the animal in a quiet posture, all of which appeared to be visually mediated. Cats with extensive lesions of the caudate nuclei do not show this profile; instead they show unspecific locomotor activity proportional to the size of the ablation and to the dose of morphine. These effects are blocked by naloxone in both intact and lesioned animals. The robustness of these results indicate that (i) the striatum is involved in the behavioral effects of morphine, and (ii) that the cat is a useful, sensitive model for the study of the behavioral effects of opiates.

Agonistic Behavior↗
PubMed2001

Aggressive behavioral phenotypes in mice.

Aggressive behavior in male and female mice occurs in conflicts with intruding rivals, most often for the purpose of suppressing the reproductive success of the opponent. The behavioral repertoire of fighting is composed of intricately sequenced bursts of species-typical elements, with the resident displaying offensive and the intruder defensive acts and postures. The probability of occurrence as well as the frequency, duration, temporal and sequential patterns of aggressive behavior can be quantified with ethological methods. Classic selection and strain comparisons show the heritability of aggressive behavior, and point to the influence of several genes, including some of them on the Y chromosome. However, genetic effects on aggressive behavior critically depend upon the background strain, maternal environment and the intruder. These factors are equally important in determining changes in aggressive behavior in mice with a specific gene deletion. While changes in aggression characterize mutant mice involving a variety of genes, no pattern has emerged that links particular gene products (i.e. enzyme, peptide, receptor) to either an increase or a decrease in aggressive behavior, but rather emphasizes polygenic influences. A potentially common mechanism may be some components of the serotonin system, since alterations in 5-HT neurotransmission have been found in several of the KO mice that display unusual aggressive behavior.

Aggression↗