Effects of ACTH1-24 on male rat behavior in an exploratory, copulatory and socio-sexual approach test.

The effect of intraventricular application of ACTH1-24 on exploratory behavior, excessive grooming, and socio-sexual behavior in male rats was studied. It appeared that ACTH1-24 (1 microgram/animal) affects both excessive grooming and exploration. Sexual performance was delayed, as expressed in latency time to ejaculation, probably because of prolonged grooming behavior. The behavioral effects of ACTH are explained in terms of enhanced attention to external stimuli.

Influence of ACTH1-24 on grooming and sociosexual behavior in the rat.

The effects of intraventricular administration of ACTH 1-24 on grooming, exploratory and socio-sexual behaviors in male rats were studied. The various behavioral elements were analyzed in terms of latency, frequency, and duration, which provided a multivariate behavioral profile. Behaviors that occur early during the test procedure had decreased, whereas behaviors displayed after the animal had spent some time in the test situation increased. Sociability, sexual approaches, and sexual preference in a sociosexual test situation were not altered by this treatment. The extinction of the response after removal of the incentive animals was delayed, however. It is concluded that ACTH1-24 did not specifically influence goal-directed behaviors. The obtained change in the behavioral profile, including the grooming pattern, rather suggest that ACTH1-24 affects mechanisms associated with attention and habituation.

Aging and sociosexual behavior in the male rat.

Senescent and young rats have been studied in a copulatory test and sociosexual approach test. The copulatory test was applied to investigate age-dependent changes in the copulatory capacity in the rat. The sociosexual approach test was used to describe motivational aspects of this behavior. Latencies, frequencies and durations of copulatory behaviors in the copulatory test and visits to various incentive animals in the approach test have been measured. Senescent rats had longer latencies and less frequencies of copulatory behaviors. In the approach test they showed less visits to the estrous female. Data were also subjected to a correlational analysis in order to relate the findings of the two tests. It is concluded that aged male rats differ from young ones in organizing their behavior in relation to time, are less social and have a less pronounced social preference pattern. In addition, the coherence between various elements of copulatory behavior was less in the senescent rat than in the young male rat, whereas the social approach patterns are more coherent in the aged male.

Neonatal vasopressin antagonist treatment facilitates adult copulatory behavior in female rats and increases hypothalamic vasopressin content.

This study confirms that i.c.v. administration of Arg-vasopressin (AVP, 20 ng) inhibits copulatory behavior in female rats (lordosis response, LR) and demonstrates that this inhibitory effect is blocked by the vasopressin antagonist (3-mercapto-3-methylbutyryl-Tyr-[Me])arginine vasopressin (dPTyr(Me)AVP, 20 ng, i.c.v.). The effects of neonatal AVP antagonist treatment on adult female copulatory behavior, hypothalamic content of AVP and AVP-like immunoreactive (AVP-ir) neurons were examined. dPTyr(Me)AVP was given to female rats 1 microgram/animal/day s.c. from day 1 through to day 7 (day 0 = day of birth). The females were ovariectomized as adults and sexual receptivity activated by submaximal doses of estradiol plus progesterone. The LR was significantly facilitated in the neonatally dPTyr(Me)AVP treated females who also showed a higher content and an increased number of AVP-ir neurons in the suprachiasmatic nucleus compared to saline controls. Functional, biochemical and immunocytochemical evidence is provided that neonatal exposure to an AVP antagonist induces persistent changes in central vasopressinergic neuronal mechanisms.

Biochemical evidence for the GABA regulation of vasopressin levels in microdissected brain structures after servo-controlled hypotension.

Discrete brain structures were analysed for gamma-aminobutyric acid (GABA) and vasopressin content in normo- and hypotensive rats treated with the glutamic acid decarboxylase inhibitor, 3-mercaptopropionic acid (MPA) and the GABAA agonist muscimol. In the normotensive group treated with MPA only, the concentration of vasopressin increased in the supraoptic nucleus, indicating an inhibitory role for GABA. In the hypotensive group a rise in the vasopressin level in the nucleus of the solitary tract was detected and the GABA level decreased in the supraoptic nucleus. Muscimol decreased the concentration of vasopressin in the nucleus of the solitary tract. The changes in the concentration of vasopressin may be a result of increased or decreased activation of the GABAergic system. The results show that the GABA- and vasopressinergic systems somehow interact although the more precise way of action remains to be clarified.

Dopamine mediated behavior and GABA influence.

The possibility of interactions between GABA and dopaminergic central nervous mechanisms in the expression of spontaneous behavior was investigated using the behavior pattern shown by male rats in an exploratory test situation. The present study corroborates the facilitatory action of low doses of the dopamine agonist apomorphine on the investigative activity element of the male rats exploratory behavior pattern, as shown previously. In addition it was found that the GABA agonist baclofen in different doses (1.2-4.8 mg/kg IP) selectively increased this activity. Pretreatment with a submaximal dose of baclofen (1.2 mg/kg) potentiated the effect of apomorphine (25 micrograms/kg), indicating that baclofen has the same effect on behavior as presynaptically active dopamine agonists. Thus GABA mechanisms might influence dopamine mediated behavior. The investigative activity which previously has been considered to reflect the adaptive state of an animal is suggested to be influenced by a changed activity in GABA neurons, DA neurons or an interaction between these two systems in the various brain structures involved in the expression of this behavior.

Ergonomics evaluation of Picture Archiving and Communication System implementations in two X-ray departments.

Two large X-ray departments in the County of Stockholm have changed from traditional analogue technology to digital imaging, including the implementation of Picture Archiving and Communication Systems (PACS). One of the departments was moved to a completely new purpose-built building and equipped with the latest technology, but for the other one the change merely meant rebuilding and adaptation of existing rooms on the premises. The objectives of the present study were to evaluate the ergonomics effects of the new technique in the two X-ray departments and to find out whether the implementation of digital imaging technique came up to expectations of improved ergonomics and work environment. Another purpose was to compare the outcomes for the two departments, in order to learn about the importance of the different implementation approaches. Questionnaires were sent out to the two departments both before the implementation of PACS and after the transition. The questionnaires covered several aspects of work conditions, such as working time, the physical and psychosocial environment, physical work load and musculoskeletal complaints, expectations from the digital technology, etc. The changeover went better than expected and even high expectations were fulfilled and surpassed. However, there were also some unexpected and distressing results; for example, a substantial increase in headaches and musculoskeletal symptoms as well as the use of pain killers among the radiologists of one of the X-ray departments.

Effect of cerebral ischemia on hypotension-induced increase in plasma vasopressin and hepatic glycogen concentration in the rat.

The effect of cerebral ischemia on the vasopressin response to hemorrhagic hypotension and on the hepatic and muscular glycogen mobilization was studied in rats. The addition of cerebral ischemia to the hemorrhage required withdrawal of significantly more blood to lower mean arterial pressure (MAP) to 50 mmHg but not if combined with ganglionic blockade. The increase in plasma vasopressin concentration during hypotension was not significantly different in rats with and without concurrent cerebral ischemia. Ganglionic blockade blunted the vasopressin response. Thus cerebral ischemia in fact attenuated the vasopressin response to hemorrhage. One hour after the insult, the hormone concentration in rats exposed to combined cerebral ischemia and hemorrhagic hypotension without ganglionic blockade was still above control levels and higher than in all other groups. Concomitantly the hepatic but not the muscular glycogen concentration in these rats was significantly lower than in the other groups.