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Biomedical subjects

H Würbel

Publications and source records attributed to H Würbel.

10 recordsLinked to original sources
PubMed2001

Ideal homes? Housing effects on rodent brain and behaviour.

Rodents used in biomedical research are typically reared in small cages that lack key features of their natural habitats. These conditions impose constraints on behaviour and brain development, resulting in altered brain functions. In this article, evidence for three different ways in which barren housing conditions interfere with brain development and behaviour is reviewed. Early environmental deprivation, thwarting of behavioral response rules, and disruption of habitat-dependent adaptation processes are shown to result in aberrant or maladaptive brain functions. Current standard housing conditions could therefore compromise the utility of rodents for research, especially in behavioural neuroscience. However, a better understanding of the animals' needs and of the environmental factors involved in the control of behaviour could offer a biological basis for refinement.

Adaptation, Psychological↗
PubMed2001

Enrichment-dependent differences in novelty exploration in rats can be explained by habituation.

In rats, exploratory activity and emotional reactivity towards novel stimuli reflect independent biological functions that are modulated differently by rearing experiences. Environmental enrichment is known to improve performance in exploratory tasks, while having inconsistent effects on emotionality. This study examined the effect of environmental enrichment on the behaviour of rats in two exploratory tasks. Male rats were reared under one of four conditions, differing in social and non-social complexity. At 9 weeks of age, exploration of a novel open field, and exploration of novel objects in the same open field following 24 h habituation, was assessed. Differences in social and non-social complexity of the rearing environment had inconsistent effects on exploration in the novel open field. In contrast, when rats were faced with novel objects in an otherwise familiar environment, exploration habituated faster with increasing stimulus complexity of the non-social environment. The social environment had no effect on this latter test. These findings indicate that environmental enrichment affects exploratory activity primarily through its effect on habituation to novelty. This effect depends on relative stimulus complexity of the rearing environment, but is independent of social factors. The present results further suggest that aversive tasks can obscure the expression of enrichment-dependent differences in habituation to novelty.

Animals↗
PubMed2001

Early social deprivation disrupts attentional, but not affective, shifts in rats.

This study examined the effects of early social deprivation in rats on 2 dissociable forms of inhibitory control of behavior that operate at 2 different levels of response selection: reversing the assignment of stimulus-reward associations within perceptual dimensions (affective shifts) and switching selective attention from 1 perceptual dimension to another (attentional shifts). Isolated subjects (isolates) and social controls (socials) were individually trained to spatial and nonspatial visual discrimination criteria on a radial arm maze. Whereas isolates and socials differed in neither acquisition nor reversal of both versions of the task, isolates were selectively impaired in shifting from spatial to nonspatial discrimination and vice versa. These findings demonstrate that isolation rearing selectively disrupts inhibitory control in attentional selection but leaves inhibitory control in affective processing intact.

Affect↗
PubMed2000

Behavioral profiles of genetically selected aggressive and nonaggressive male wild house mice in two anxiety tests.

Artificially selected aggressive (SAL) and non-aggressive (LAL) male house mice were tested in a hexagonal tunnel maze and light-dark preference (LD) box to determine if the bidirectional selection for aggressive behavior leads to a coselection for different levels of trait anxiety. The tunnel maze consists of an open, brightly lit central arena surrounded by a complex system of interconnecting tunnels. As in the LD box, animals which spend less time and are less active in the brightly illuminated section of the maze are considered to have higher anxiety levels. In the tunnel maze, the LAL mice showed more exploration and spent more time in the central arena than the SAL animals, but only during the final 2 min of the 6-min test. This reduced preference for the central arena was not due to general inactivity or a failure of the SAL to find the central arena and indicates a higher level of state anxiety in the aggressive animals. In contrast, no "anxiety-like" differences were found in the LD box, either for the percentage of time spent in the light compartment or for the number of crossings. SAL males actually showed higher levels of moving and rearing, and lower levels of freezing, than did LAL males.

Aggression↗
PubMed1996

Prevention of stereotypy in laboratory mice: effects on stress physiology and behaviour.

According to the coping hypothesis, the adaptive significance of stereotypies in barren housing conditions may lie in their potency to attenuate the deleterious consequences of chronic stress. Present evidence from experimental studies is ambiguous. When Zur:ICR mice were selectively prevented from stereotypic wire gnawing at the cage lid, the previous amount of stereotyped behaviour after a short-term decrease in activity was compensated by variable active behaviour on the cage floor. This change in behaviour was associated with a short-term elevation of serum corticosterone concentrations 24 h after stereotypy prevention. However, 3 days later corticosterone levels were back at pretreatment base levels. Both behavioural and physiological short-term effects were caused by the impact of prevention on behavioural organization. They disappeared as soon as new habits were established, even though they were not stereotyped. In contrast to the predictions of the coping hypothesis, prevention of stereotypy had no significant effects on chronic measures of both the sympathetic-adrenal-medullary system and the hypothalamus-pituitary-adrenal system. Thus, there is no evidence that stereotypic wire gnawing reduces chronic stress in Zur:ICR mice. This implies that coping with stress is not a general aspect of cage-induced stereotypic behaviour.

Adrenal Medulla↗
PubMed1996

Repeated blood collection in the laboratory mouse by tail incision--modification of an old technique.

Twenty years ago, tail incision for collecting serial blood samples from mice was introduced as a new technique. Despite a number of advantages over established methods, it has not become a frequently used technique. This report describes modifications of blood collection from mice by tail incision that allow obtaining rapid (1-1.5 min) serial blood samples (40-150 microliters) from unanaesthetized laboratory mice. Evaluation of corticosterone concentrations in the blood plasma from repeated samples indicated that subsequent samples were unaffected by the procedure. Furthermore, histopathological examination demonstrated that repeated bleeding did not cause any lasting harm to the animals. Blood collection by tail incision may, therefore, be of particular interest for studies that attempt to relate physiological measures to behavioral responses in laboratory mice, and may contribute to the refinement of animal experimentation according to the principles of the Three Rs.

Animals↗
PubMed1989

Increased peripheral vasoconstrictor reaction upon local cold in patients with coronary heart disease.

A local cold exposure test of the nailfold capillaries produces a typical flow stop reaction in 88% of patients with Raynaud's phenomenon. We applied this test to 12 patients with variant angina and compared the results with the findings in 2 control groups of 12 patients each, matched for age and sex: One group with chronic stable angina and one without heart disease. We found a flow stop with cold exposure in 9/12 patients with variant angina (mean duration 24 s), in 6/12 patients with chronic angina (mean 11 s), and in 1/12 normal controls without heart disease (mean 1 s). The frequency and duration of the flow stop was significantly higher in patients with variant angina (p = 0.002) and in patients with chronic stable angina (p = 0.02) than in normal controls. Patients with variant angina also tended to have an increased frequency and longer duration of the flow stop than those with chronic stable angina (p = 0.09). Administration of sorbidilate preparations and nifedipine resulted in a decrease of the mean flow stop duration from 23.5 to 10.8 s in patients with variant angina (p = 0.03). The strong association of a vasoconstrictive reaction in finger microcirculation and coronaries in patients with variant angina suggests a vasospastic tendency with manifestation in different vascular regions.

Adult↗
PubMed1989

Local cooling test for clinical capillaroscopy in Raynaud's phenomenon, unstable angina, and vasospastic visual disorders.

A local cooling test produces a typical flow stop reaction in nailfold capillaries in 88% of patients with Raynaud's phenomenon, but only in 15% of healthy controls. A stop reaction occurred in 9 of 12 patients with Prinzmetal variant angina, exceeding significantly that in 2 of 12 matched control subjects. Also in patients with reversible visual disorders presumably due to vasospasm, the test resulted in a stop reaction in 16 of 25 cases exceeding that in control. In both of these patient groups the cooling test as well as the symptoms reacted favorably to nifedipine. Thus, the local cold exposure test appears to be useful for objective clinical examination not only of patients with Raynaud's phenomenon but also of patients with vasospastic syndromes such as variant angina and visual disorders.

Adult↗