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P F Brain

Publications and source records attributed to P F Brain.

At least 55 records · Page 3Linked to original sources
PubMed1988

Studies on the effects of the antiandrogen cyproterone acetate on social encounters between pairs of male mice.

An attempt was made in two experiments to reinvestigate the effects of the antiandrogen cyproterone acetate (CA) on mouse social behavior in a variety of ethologically-assessed paired encounters. The data confirm that CA reduces offense (threat and attack) in animals when both subjects receive the material but that CA has no such action in other pairings. This suggests that CA's major suppressive effect on "hostility" is expressed in mice via a reduction in "attack-promoting" pheromone production. Indeed, there was evidence in the more chronic study that CA, could augment (via a central mechanism?) offense in subjects paired with docile anosmic opponents. Changes in defense were largely responses to variations in the degree of attack to which animals were subjected. The antihormone also had actions on other aspects of behavior including sexual activity, social investigation and immobility in such tests. CA had a potent suppressive action on the weights of sex accessory glands. The data do not suggest that CA can be used as a specific antihostility agent.

Androgen Antagonists↗
PubMed1987

Glucose improves attention and reaction to frustration in children.

There have been many suggestions that both dietary sugar and the level of blood glucose may be associated with abnormal behaviour. To examine this question 60 six- and seven-year old children were given a drink that contained either 25 grams of glucose or a placebo towards the end of the school day. They were then subjected to one test that required sustained attention and to a second that was intentionally frustrating. Those given the drink containing glucose were more capable of sustaining attention and showed fewer signs of frustration.

Attention↗
PubMed1986

Alcohol and social behaviour in group-housed female mice.

Group-housed female mice were injected IP with 0, 0.5, 1.0 or 2.0 g/kg of ethanol. Twenty min after injection, the animal's responses in a neutral cage to a docile male "standard opponent" were videotaped for 500 sec. The tapes were subsequently analysed in terms of the total times allocated by the females to non-social, social/sexual, aggressive and timid activities. The frequency of occurrence of acts and postures associated with the above categories was also determined. Similar females given the same doses were used to assess the blood alcohol concentrations 20 min after injection. Timid behaviour was greatly increased by high doses of ethanol, especially as a consequence of increases in the element 'cringe'; at the low dose 'cringe' was decreased in frequency. Social/sexual behaviour was also influenced in a biphasic manner, low doses increasing and high doses reducing such activity. The drug modified some elements of non-social behaviour in a manner suggesting motor impairment at high doses. There was no evidence that any dose of ethanol induced aggressiveness in these animals. There did not seem to be a simple dose-response effect.

Aggression↗
PubMed1986

Effects of gender, gonadectomy and social status on attack directed towards female intruders by resident mice.

Small unisexed groups (triads) of either male of female Swiss strain mice attack lactating intruders introduced into their home-cages. Female residents are, however, generally much more aggressive towards such intruders than are males. Ovariectomy of female residents (on day 15 or day 50 of life) has little effect on such responses, but castration of male residents significantly increases their attack on lactating intruders to a level resembling that of females. The introduction of the lactating female into the home-cage of sham-operated or gonadectomized male or female residents also enhances intragroup fighting with males (irrespective of their endocrine status) being the more aggressive. Finally, the social status of the male alters the response towards lactating females. Dominants generally show higher levels of attack, an effect that can be augmented by castration.

Aggression↗
PubMed1986

A brief review comparing the effects of sex steroids on two forms of aggression in laboratory mice.

This brief review examines the roles of sex steroids in two forms of "aggression" in laboratory mice. The social conflict induced in male mice by individual housing or reproductive experience was contrasted with the attack shown by small groups of female mice on lactating intruders. Gonadectomy of males largely abolishes the former response but actually augments the latter activity in male subjects. Testosterone, estradiol and 5 alpha-dihydrotestosterone all restore social conflict in gonadectomized male mice but these sex steroids inhibit attack on lactating female intruders by gonadectomized males. The data clearly confirm that there is no simple relationship between a particular hormone and "aggression." These forms of attack may serve very different functions even though they involve similar action patterns and distributions of bites on the attacked animal. A tentative discussion is included about the roles of these activities.

Aggression↗
PubMed1986

Effects of naloxone upon the behavioural organisation of specific defeat activities in intruder mice: assessment by cluster analysis.

The present experiment examined the effects of naloxone (0.5, 2.5 and 12.5 mg/kg) upon the responses of male Swiss mice to attack by aggressive male conspecifics in the resident-intruder paradigm by measuring the time spent in broad behavioural categories, frequency of individual acts or postures, and performing a cluster analysis of activities according to their frequency and position within the behavioural sequence. The former two measures detected little naloxone-induced change in behaviour. Cluster analysis revealed changes in behavioural organisation which suggested modification in the motivation and/or function underlying specific defeat behaviour.

Aggression↗
PubMed1986

Effects of naloxone administration on attack by castrated male mice on lactating intruders.

The effect of the narcotic antagonist naloxone (a mu blocker at low doses) on the attack displayed by castrated male mice towards lactating intruders was investigated. Naloxone at doses of 1 mg and 2 mg/kg decreased attacks an effect which was also evident to a lesser extent at 0.75 mg/kg. These findings suggest a role for endogenous opiates in the expression of this form of aggression although one must warn that naloxone at some of the higher doses used here can influence kappa and delta receptors as well as gabaergic activity. The interrelationships between endogenous opioids, gabaergic neurotransmission and gonadal hormones in the regulation of this attack response are discussed.

Aggression↗
PubMed1986

Effects of different doses of cyproterone acetate (CA) on preputial gland structure and activity in intact male mice.

The preputial is an androgen-dependent structure which appears to be used in pheromonal signalling in rats and mice. The structure of representative glands from intact oil injected male laboratory TO strain mice was contrasted with tissue from intact counterparts treated with the anti-androgen cyproterone acetate (CA). Sixteen days of an i.m. application of a modest range of CA doses (0.5, 1.0 and 2.0 mg/day given as oily solutions) and a variety of control treatments were used to assess influences on the structure and function of the preputial. The glands of intact male mice treated with oil were well-developed and actively secreting with parenchymatous acini at different stages of maturation. Such glands are generally highly Sudanophilic, with the lipophilic stain concentrated in acini in frozen sections and many acini are compressed by their neighbours to assume irregular shapes. Wax and frozen preputial sections from intact subjects treated with 0.5 or 1.0 mg CA were, in contrast, less well-developed and had fewer and smaller lipid droplets. Treatment of counterparts with 2 mg CA reduced acinar number and diameter in both wax and frozen sections with a concomitant increase in the proportion of connective tissue. The data confirm that this anti-androgen antagonizes the androgen secreted by the testis and adrenal cortex in terms of its expression of function on the preputial gland. These data provide further evidence that cyproterone acetate's suppressive actions on murine aggression are primarily via its ability to depress the secretion of odour cues that facilitate attack.

Animals↗
PubMed1986

The application of ethopharmacological techniques to behavioural teratology: preliminary investigations.

Ethopharmacological techniques were used to study the behaviour of the offspring of mice treated with different drugs before and after parturition. The "standard opponent" test was used and the animal's behaviour was recorded on videocassettes. It was found that ethyl alcohol, glutamate, cyproterone acetate, medroxyprogesterone acetate, corticosterone and thiourea changed, while lithium chloride and diazepam had no effect on social, defensive, threatening and aggressive behaviour.

Aggression↗
PubMed1986

Effects of ethanol on social behaviour directed towards male intruders by lactating Swiss mice.

Ethanol (0.5, 1.0 or 2.0 g/kg) was given intraperitoneally to lactating Swiss strain mice and the animal's response to a docile male intruder was assessed using a videotape analysis that estimated the time that the females allocated to non-social, social/sexual, aggressive and timid categories of response. No evidence was produced in this study that alcohol augmented aggression although conditions were certainly conducive for such an effect. Alcohol does, however, modify aspects of social behaviour in lactating female mice.

Aggression↗
PubMed1985

Substrate soiled by an unfamiliar conspecific modifies opioid activity in mice placed in novel environments.

Naloxone induces behavioural changes in rodents exposed to novel environments, indicating the involvement of endogenous opioid mechanisms in these situations. The present study investigated whether soiled sawdust substrate from the cage of an unfamiliar, isolated, male conspecific modifies the effect of naloxone (0.5 or 12.5 mg/kg) upon behaviour of mice in an open field test situation. There was little difference between the effects of naloxone upon the frequency of acts or postures shown in the soiled and unsoiled environments. Cluster analysis of the activities according to their position and frequency in behavioural sequences, revealed variations in behavioural organisation in these two situations in control animals, and differential responses to naloxone administration. The data are discussed in terms of an involvement in behaviour of opioid mechanisms which can be modified by non-painful, biologically-relevant, aversive stimuli such as unfamiliar, conspecific-soiled substrates.

Animals↗
PubMed1985

Comparisons of the influence of morphine sulphate, morphine-3-glucuronide and tifluadom on social encounters in mice.

The influences of morphine sulphate, morphine-3-glucuronide and tifluadom on social encounters were compared in male and female mice that were allowed to interact with an anosmic male partner. The drugs were compared, as morphine sulphate is thought to act via mu, and tifluadom via kappa opiate receptors; morphine-3-glucuronide is the breakdown product of morphine. Neither morphine sulphate nor morphine-3-glucuronide significantly influenced inter-male social encounters. However, tifluadom increased non-social and decreased social behaviour, while increasing timid/defensive activities. Tifluadom did not significantly influence the behaviour of female mice in this social encounter: in contrast both morphine sulphate and morphine-3-glucuronide decreased timid/defensive behaviour and stimulated non-social behaviour. It was concluded that the results could be explained by suggesting that morphine sulphate decreases whereas tifluadom increases timidity.

Animals↗
PubMed1985

An ethological analysis of the effects of tifluadom on social encounters in male albino mice.

The effects of treatment with saline, 0.5 or 1.0 mg/kg of tifluadom were assessed 30 min after injection on the behaviors shown by isolated Alderly Park strain mice in their home cages in the presence of an anosmic 'standard opponent' mouse. Tests involved videotaping encounters and examining the incidences of 45 behavioral elements and their sequences (by producing 'dendrograms'). The kappa agonist appeared to stimulate olfactory exploration of the substrate at the expense of other forms of non-social exploration; it suppressed olfactory investigation of the 'standard opponent'; reduced some aggressive elements and increased immobility (at reportedly non-sedative doses) and fearful activity. The 'dendrograms' revealed that tifluadom greatly altered the relationships between some elements. The higher dose of the kappa agonist resulted in self-grooming and digging (displacement?) being associated with the agonistic items suggesting that these animals evidenced increased timidity in social encounters.

Aggression↗
PubMed1985

Pre-natal administration of diazepam improves radial maze learning in mice.

A number of studies have found that the peri-natal exposure of rodents to diazepam alters their adult behaviour. Adult male mice, treated with diazepam or appropriate controls during pregnancy, were examined in terms of their ability to learn a radial maze. Those animals receiving diazepam prior, but not after birth, learnt the maze significantly more rapidly. The results are discussed in terms of the possible involvement of the hippocampus in this influence of diazepam.

Age Factors↗
PubMed1984

Comparison in the mouse of the effect of the opiate delta receptor antagonist ICI 154129 and naloxone in tests of extinction, passive avoidance and food intake.

The effects of 30 and 80 mg/kg ICI 154,129, an opiate delta receptor antagonist, were compared with those of 0.1 and 10 mg/kg naloxone using tests of food-intake, passive avoidance and extinction in mice. Whereas naloxone depressed food intake and facilitated extinction, ICI 154,129 failed to affect food intake, passive avoidance or extinction although the mice reared significantly more during the test of food intake.

Animals↗