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An attempt was made using a combination of simple experimental manipulations and videotape recorder (VTR) analysis of bite targets employed to determine whether electroshock-induced attack on anosmic opponents in laboratory mice was an offensive or a defensive behaviour. VTR analysis suggested that ventral surface biting was more evident in this form of attack than in social conflict. Individually- and group-housed males showed similar levels of fighting on exposure to electroshock, but dominant males from pairs showed greater attack than their subordinate partners. Zinc sulphate-induced anosmia, 36 h of food deprivation, castration and lithium chloride treatment reduced electroshock-induced attack. Although significant changes were not obtained, there was some evidence that acute treatment with dexamethasone or ACTH augmented this behaviour. The direction of these changes is similar to that seen with social conflict, and it is suggested that electroshock-induced attack in the mouse (unlike the rat) is largely an aggressive offensive behaviour. The high incidence of ventral surface biting may be a consequence of the upright postures assumed on subjecting the animals to electroshock., (Copyright © 1981. Published by Elsevier B.V.)

The behavioural influence of the anti-aggressive drug Fluprazine (DU 27716) was examined using an ethological technique. The drug inhibited aggressive behaviour but not in an entirely specific way. Fluprazine also stimulated non-social and defensive/flight behaviours; there was a greater tendency for drug-treated animals to avoid their opponents. Using an automatic recording technique the drug's anti-aggressive action was monitored for 23 h. There was a potent anti-aggressive influence that lasted for up to 4 h. However, when the drug-effect wore off there were bouts of fighting. Over 23 h Fluprazine did not significantly decrease the total aggression recorded.

The influence of a range of commonly used psychotherapeutic drugs on the ultrasonic calling of mouse pups was assessed. The major tranquilizers chlorpromazine and haloperidol were without effect. Whereas tranylcypromine and imipramine were also inactive, amitriptyline suppressed the rate of calling. Some anxiolytic compounds such as meprobamate and amobarbital were without influence, although others such as diazepam, chlordiazepoxide and ipsapirone decreased the number of calls. The influence of these drugs on body temperature was measured, as it is known to markedly influence the rate of ultrasonic calling. Although six out of ten drugs decreased body temperature, there was no evidence that this was related to the rate of ultrasonic calling. The possibility that the recording of ultrasonic calls could be used to screen for psychotropic activity is discussed.

The influences of the mu blocker naloxone and the novel opioid delta receptor antagonist ICI, 154, 129 on videotaped encounters between individually-housed, male Swiss mice and anosmic male 'standard opponents' were assessed using a variety of ethological analyses. The effects of drugs were studied on individual elements and on the times allocated by subjects to broad categories of behaviour. Neither of the drugs significantly altered times allocated to broad categories of behaviour. Both doses of both compounds significantly increased the incidences of some 'fearful'/defensive postures. A more detailed analysis considered the effects of the drugs on the sequences of postures used in the resident's behaviour. This involved the generation of 'dendrograms' which provided support for the view that both naloxone and ICI 154, 129 altered the associations between behavioural elements seen in saline controls (especially at higher doses) and that the effects of these antagonists were qualitatively different., (Copyright © 1985. Published by Elsevier B.V.)

The hypothesis that 5-alpha-androst-16-en-3 alpha-ol increases the sexual arousal of the human female was examined. This substance is produced by the male and has been suggested to be a possible human pheromone. Groups of female subjects were asked to read either a neutral or a sexually-arousing passage in the presence of either androstenol or a placebo. Although sexual arousal was clearly manipulated by the experimental conditions, there was no evidence that androstenol influenced sexual feelings.

The interactions between isolated resident mice and anosmic, juvenile, submissive and dominant intruders were studied; the responses of intruder mice to being attacked and the distribution of bites on these subjects were investigated. Anosmic, juvenile and (trained) submissive intruders did not attack residents; they did, however, show differences both in thir responses to being attacked and their ability to avoid bites to particular regions of their body surface. These differences are likely to make it difficult to extrapolate between tests that employ different types of intruder. Trained dominant intruders showed substantial attack on resident mice and a very different pattern of attack was generated by this type of encounter. The study confirms that, while "standard opponents" are useful means of assessing aggressive motivation, the pattern of fighting they produce differs depending on their background., (Copyright © 1981. Published by Elsevier B.V.)

The influence of a novel opiate delta receptor antagonist, ICI 154,129, and naloxone on social interaction and on behaviour in an open field were compared. At a dose thought to optimally block the delta receptor, ICI 154,129 produced open field behaviour typical of a non-emotional animal: this drug decreased social investigation and the latency to attack. In contrast, naloxone was largely without effect in these tests.

Rats housed in impoverished environments often show greater behavioral deficits after receiving brain lesions than to rats housed in standard or enriched environments. However, the resemblance between the effects of social isolation and those of hippocampal lesions in rats prompted the suggestion that rats socially isolated at weaning rather than grouped counterparts may show less behavioral change after sustaining dorsal hippocampal lesions when adult. In socially reared rats, hippocampal lesions produced increased ambulation and object contact in an open field, reduced passive avoidance in a runway task, and produced faster acquisition of active avoidance in a shuttle box, but there were no such differences in isolation-reared rats. Ambulation and object contact in isolates were intermediate to those of rats with lesions and intact group-housed rats, and the behavior of isolates during passive and active avoidance training was generally similar to that of grouped rats with lesions. The introduction of a distractor during approach training in an alley reduced running speeds more in rats with lesions than in controls. The several significant interactions between housing state and lesion state suggest that neural pathways associated with the hippocampal formation may mediate some behavioral effects of differential housing.

The popular notion that a tendency to develop low levels of blood glucose is the cause of a range of behavioral problems is reviewed. It is concluded that it is inappropriate to use the glucose tolerance test as a test of the tendency to develop reactive hypoglycemia. Instead, a meal tolerance test, in which glucose is administered in the presence of fat and protein, should be the method of choice. The use of a meal tolerance test strongly suggests that reactive hypoglycemia rarely results, except in a few exceptional individuals. Three situations are described in which a correlation between a tendency to develop moderately low levels of blood glucose during a glucose tolerance test (not hypoglycemic values) and the tendency to act aggressively have been reported. The significance of these data is unclear but several possible mechanisms by which glucose may influence behavior are discussed.

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.

The influence of opioid drugs on agonistic behaviour is reviewed and an experiment is reported that examines the impact of U-50488 (a kappa agonist) and DAGO (a mu agonist) on the social encounters of male and female mice interacting with anosmic male partners. Although DAGO did not significantly influence inter-male social encounters, U-50488 decreased social investigation, increased timid/defensive behaviour and potently suppressed aggression. In contrast, U-50488 did not significantly influence the behaviour of timid female mice, whereas DAGO decreased social and timid/defensive behaviour. It was concluded that a kappa mechanism increases whereas a mu mechanism decreases submissive behaviour.

Alterations in immune function have been commonly reported in elderly persons. We have examined the effect of age on the responsiveness of natural killer (NK) cells to in vitro stimulation with recombinant interleukin-2 (rIL-2) and in vivo stimulation with exercise in 17 healthy subjects (8 young and 9 old). The old subjects were found to have NK cell numbers and function that were not significantly different from the young subjects at baseline. They also responded as well as the young subjects to rIL-2 stimulation of NK cells in vitro. In response to maximal bicycle ergometry exercise, there was a marked rise in NK activity in the old (7.52 +/- 1.71 LU/10(6) pre-exercise vs 15.20 +/- 3.27 LU/10(6) post-exercise, p less than .03) and the young (6.29 +/- .48 LU 10(6) vs 14.56 +/- 1.86 LU 10(6), p less than .005) subjects. Lymphocytes bearing the NK marker Leu 11a also rose significantly post-exercise in both old and young subjects. We conclude that healthy elderly subjects increase their NK activity in response to the acute stressor, exercise, at least as effectively as do young subjects.