Cat Odor Research Articles

Chlordiazepoxide reduces the generalised anxiety, but not the direct responses, of rats exposed to cat odor

Rats were treated for 5 days with vehicle or chlordiazepoxide (CDP, 5, 10, or 20 mg/kg/day) and then exposed to a cloth impregnated with a neutral or cat odor. Those exposed to cat odor made significantly fewer contacts with the cloth and spent less time in contact with it and more time sheltering than those exposed to the neutral odor. CDP (5 mg/kg) significantly increased the time in contact with both odor cloths, but there were no other significant effects in the cat odor group. Rats previously exposed to cat odor showed significant anxiogenic responses in the social interaction and elevated plus-maze tests that were significantly reversed by CDP. There was no reduction in the responses to the cat odor on a second occasion as a result of the first exposure occurring after treatment with CDP (5 or 20 mg/kg). The anxiogenic effects of pentylenetetrazole (20 mg/kg) as detected in the social interaction and plus-maze tests were unaffected by prior odor experience. It is suggested that during exposure to the cat odor the responses of rats reflect avoidance components of a phobic anxiety state. Benzodiazepines are relatively ineffective against these responses in contrast to their efficacy against the generalised anxiety responses detected in the social interaction and plus-maze tests.

Behavioral consequences in animal tests of anxiety and exploration of exposure to cat odor

Rats exposed to a cloth impregnated with cat odor showed a decreased number of contacts with the cloth and time in contact with it and increased time sheltering from it. Exposure to the odor of rat blood produced similar, though less marked, changes and also increased the number of occasions the rat sought shelter. Exposure to the odor of disinfectant changed only the time in contact with the cloth. Exposure to cat odor also resulted in anxiogenic responses in the social interaction and elevated plus-maze tests that could be detected up to 1 h, but not 24 h, after odor exposure. Decreased exploration in the holeboard could also be detected up to 1 h, but not 24 h, after exposure to cat odor. The time in contact with the cloth, the incidence of, and time spent sheltering did not decrease over five successive exposures to the odor of a cat. The number of contacts with the control odor cloth increased over successive exposures, but contacts with the cat odor cloth did not change over successive exposures. The decreased exploration in the holeboard, as a result of prior exposure to cat odor, showed rapid habituation, as did the anxiogenic response detected in the social interaction test, whereas that detected in the plus-maze persisted for up to five odor exposures.

MK-801 produces a reduction in anxiety-related antipredator defensiveness in male and female rats and a gender-dependent increase in locomotor behavior.

The present study investigated the effects of the non-competitive NMDA antagonist MK-801 (0.04-0.16 mg/kg), on antipredator defensive reactions of male and female rats in three paradigms comprising the Anxiety/Defense Test Battery (A/DTB). In order to facilitate interpretation of data from the above study, the behavioral effects of the compound were also assessed in the non-threatening environment of the home cage. The data indicate a marked gender difference in the locomotor effects of the compound with females, but not males, showing a dose-dependent increase in general locomotor activity, a decrease in freezing, and a loss of balance at the highest dose, in both non-threatening and threatening contexts. The behavioral profile for males in the A/DTB included decreased orientation to and proxemic avoidance of the cat stimulus or stimulus site, and increased transits and eating in the cat situation. Contacts with the cat odor stimulus were increased, as was normal, curved back, locomotion in this test. In the absence of non-specific locomotor effects for males, this profile for the A/DTB provides convincing evidence for anxiety/fear reduction with MK-801. While locomotor effects tended to mask the putative anxiolytic properties of the compound in females, evidence remains from behavioral changes not attributable to a locomotor influence to indicate anxiety/fear reduction in this sex.

The anxiety/defense test battery: Influence of gender and ritanserin treatment on antipredator defensive behavior

The anxiety/defense test battery has been developed to measure defensive reactions in laboratory rats to both direct exposure to, and stimuli associated with, a natural predator, the domestic cat. The present investigation confirmed earlier findings with each test providing a distinct behavioral profile following exposure to predator stimuli. In addition, the data showed a consistent gender difference in a number of these behavioral measures, indicating that females are more defensive than males. These effects included reliably higher levels of cat avoidance and crouching, with lower levels of transits, lying and drinking for cat-exposed females. Similarly, females exposed to a cat odor stimulus showed a reliably higher level of stretch attend and flat back approach behaviors (risk assessment) towards the stimulus block. The 5-HT 2 antagonist, ritanserin, failed to provide significant indication of anxiolytic activity, and had minimal influence on antipredator defensive behavior. An important exception to this profile was a reliable decrease in stretch attend behavior to a cat odor stimulus in females but not males. Overall, these findings suggest a complex relationship between gender, antipredator defensive behavior, and anxiolytic drug treatment.

Pregrouping aggression and defense scores influences alcohol consumption for dominant and subordinate rats in visible burrow systems

Five male/two female rat colonies were established in visible burrow systems, with males selected for pregrouping attack scores and also evaluated in open field and cat odor tests. Dominant-subordinate pregrouping attack differences suggested that the males becoming dominant are those showing more persistent and higher level attack. For six colonies showing dominant-subordinate behavioral differences, pregrouping defense tests failed to predict subordinate status. However, pregrouping defense scores were reliably correlated with subordinate pre-postgrouping change scores for voluntary ethanol consumption. Subordinates showed higher ranked ethanol consumption than dominants, but these groups were not different on pregrouping ethanol consumption. Subordinate postgrouping ethanol consumption was positively correlated with pregrouping attack toward an adult intruder, consonant with previous findings that highly aggressive subordinates are the targets of more intense attack by dominants. These results provide further support for a view that subordination stress increases voluntary ethanol consumption in male rats and suggest some additional individual differences factors that may be involved in increased ethanol consumption for male subordinates. © 1992 Wiley-Liss, Inc.

“Paradoxical” effects of morphine on antipredator defense reactions in wild and laboratory rats

In a Fear/Defense Test Battery, measuring defensive reactions to a present, approaching and contacting predator, the highest dose of morphine tested (7.5 mg/kg) reliably reduced vocalization to dorsal contact, to vibrissae stimulation, and to an anesthetized conspecific in laboratory-bred wild R. norvegicus. Except for a dose-dependent reduction in flinch/jump reactions to dorsal contact (taps), other defensive behaviors (flight, freezing, etc.) were not reliably altered by morphine treatment (0, 1.0, 2.5, 7.5 mg/kg). Vocalization responses to vibrissae stimulation in wild-trapped R. rattus were reliably increased following naloxone (1.0 and 10.0 mg/kg) administration, lending support for opiate receptor involvement in the mediation of defensive vocalization. In the Anxiety/Defense Test Battery, measuring defensive reactions to situations associated with a predator (cat) or with cat odor, laboratory rats showed no decrease in defensive behavior with morphine (0, 1.0, 5.0 mg/kg). In direct contrast to the above findings, the effects of morphine treatment in this test battery suggested a generalized increase in defensiveness to noncontacting and nonpainful threat stimuli. These effects included a decrease in time spent near the cat compartment, with a complementary increase in time spent at maximum distance, a decrease in transits between these sections, an increase in crouching, and a decrease in grooming and rearing. This pattern of results suggests that morphine may have two opposing effects on defensive behavior, a generalized enhancement, together with a more specific reduction of responses to tactile or painful stimulation. A very widespread pattern of reliable sex or sex x drug effects in the Anxiety/Defense Test Battery was in good agreement with previous reports of sex differences in these tests, with females generally more defensive than males. Consonant with previous findings, no reliable sex differences were found with the Fear/Defense Test Battery, although several values approached an acceptable level of statistical significance.

Sex effects in defensive behavior: Baseline differences and drug interactions

Female rats consistently show a pattern of differences in defensive behaviors compared to males which parallel the effects of exposure to a nonpainful threat stimulus (cat or cat odor) in the same tests and measures. These indications of greater defensiveness for females are particularly common in situations involving potential, as opposed to actual and present, threat, a factor which probably also reflects ceiling or floor effects in situations involving very intense defensiveness. In addition, pharmacological studies indicate sex differences in the effects of selective serotonin (5-HT) receptor agonists and antagonists on defensive responding. These findings indicate that sex effects must be considered in studies of the pharmacological control of defensive behaviors, and suggest that responsivity to sex effects may be an additional criterion for the suitability of animal models of anxiety.

Prolonged exposure to conspecific and predator odors reduces fear reactions to these odors during subsequent prod-shock tests

In Experiment 1, four groups of male rats were given a session as an intruder in either aggressive (i.e., alpha) or nonaggressive colonies of conspecifics and later received either a 2-h exposure to the odors of the alpha colonies or an exposure-control session with the odors of a nonalpha colony. Two additional groups of rats that had been attacked and defeated by alpha residents were later given a 12-h exposure session with alpha-colony odors or nonaipha-control odors. Twenty-four h after the colony-intruder session, all subjects were given a single 6.5-mA shock from a prod with alpha-colony odors present in the bedding of the test chamber. Attacked rats that had been given exposure-control sessions showed significantly less prod burying and greater freezing than nondefeated subjects. This implies that the alpha-colony odors elicited conditioned fear. In contrast, the attacked subjects that had been given a pretest exposure session with alpha-colony odors showed significantly more prod burying and significantly less freezing. This suggests that the alpha-odor exposure resulted in the extinction of fear to these odors. Furthermore, the 12-h exposure to alpha-colony odors was found to be more effective in reducing fear-mediated responses than was the 2-h exposure. In Experiment 2, three groups of rats were exposed to a cat while they were in a protective cage; later they were given a 12-h exposure session with cat odors, a 12-h exposure-control session with no cat odors, or no exposure treatment. Compared with the two control groups, the subjects that were exposed to cat odors showed less freezing during subsequent prod-shock tests in the presence of cat odors, but they did not show prod burying. The reported changes in fear-mediated reactions to the odors of conspecifics and a predator are discussed in terms of both associative and nonassociative processes.

Effects of cat exposure and cat odors on subsequent amphetamine-induced stereotypy

The effect of exposure to a cat, as a predatory stressor, was examined in male and female rats during subsequent tests of amphetamine-induced stereotypy in which cat odors were present or absent. Rats in Group C/O were given a 15-min exposure session to a male cat while they were protected in a wire cage. They were then given an IP injection of d-amphetamine (1 mg/kg) and tested 30 min later for stereotypy in the presence of cat odors (soiled cat litter). Rats in Group NC/O were given a no-cat-exposure control session, and amphetamine tested with cat odors. Groups C/NO and NC/NO were both tested without cat odors (fresh litter), with the former group having been previously exposed to a cat. During the 90-min test sessions, female rats showed significantly more stereotypy than males. More importantly, the male subjects in group C/O exhibited significantly more stereotypy than the males in the other groups, and group NC/NO males showed the least amount of stereotypy. These findings clearly indicate that amphetamine reactivity is influenced by prior exposure to a predator, the presence of predatory odors during testing, and the subject's sex.

The effects of ethanol and diazepam on reactions to predatory odors

In a straight alley containing a cat odor stimulus rats show high rates of risk assessment, including flat back approach and stretch attend behaviors oriented toward the threat stimulus and contact with the stimulus. In this situation, diazepam (2.0 and 4.0 mg/kg) significantly reduced risk assessment measures (flat back approach + stretch attend), while not reliably altering control locomotion (curved back). In combination with earlier findings that the same doses of diazepam reliably increased risk assessment from a movement arrest baseline, these results strongly support a behavioral model of anxiety involving predictable nonmonotonic changes in risk assessment as a function of anxiety reduction. In comparison to diazepam, ethanol had less pronounced effects on the Cat Odor Test, as in earlier tasks of reactivity to potential threat. However, reliable dose × time interactions for risk assessment measures suggest ethanol effects similar to those of diazepam but most pronounced in initial stages in the test session.

Influence of conspecific and predatory Stressors and their associated odors on defensive burying and freezing responses

In Experiment 1, male rats were exposed to either aggressive (i.e., alpha) or nonaggressive conspecific colonies and tested 24 h later, with or without alpha odors, for freezing behavior and burying of a wall prod that had been the source of a brief electric shock. The results indicated that prior defeat experience and the presence of alpha odors alone during testing had no significant effects, but the combination of prior defeat and alpha-odor testing significantly decreased burying and increased freezing behavior. In Experiment 2, we examined the effects of noncontact exposure to a cat, as a predatory Stressor, during subsequent prod-shock tests involving the presence or absence of cat odors. Exposure to a cat failed to disrupt later prod burying and did not produce freezing. However, the presence of cat odors during testing significantly reduced the amount of defensive burying,without resulting in an increment in freezing. In Experiment 3, rats were given 1, 5, or 30 inescapable preshocks in the presence of either cat odors or a hedonically neutral citronella odor and were tested 24 h later for prod burying and freezing with or without these odors. Both the cat and the citronella odors resulted in a significant reduction in burying and an increase in freezing for rats given 5 and 30 preshocks and tested in the presence of these respective conditioned odors. For the groups that were given 5 preshocks, preshock and later testing in the presence of cat odors resulted in significantly less prod burying and more freezing than for rats that were preshocked and tested in the presence of citronella. The findings of these three ethoexperimental studies are discussed in terms of the learned-helplessness theory, the stress-coping-fear-defense (SCFD) theory, and the concept of selective CS-US associability.

Changes in spontaneous, odor modulated and shock induced behavior patterns following discrete olfactory system lesions

Three groups of male hooded rats were preoperatively matched and then sham operated (SHAM), bilaterally lateral olfactory tract lesioned or anterior olfactory nucleus/anterior commissure lesioned. In one experiment, spontaneous behavior patterns emitted in an exploration field containing different odors were quantified during satiated and food deprived conditions. In other experiments, flinch and jump thresholds to electric shock and running patterns in an appetitively motivated straight alley experiment were measured. All lesioned animals were hyperactive and typically froze and groomed less than SHAMs while sniffing and rearing patterns differentiated the lesioned and SHAM groups in several ways. All animals had similar flinch and jump thresholds and also emitted similar types of responses to electric shock. In the straight alley, odors from normal and stressed rats had little effect on the running time of the experimental animals while a faint cat odor strongly inhibited SHAM running behavior. Responses to a novel chemical odor (trimethylpentane) and to changes in the alley floor or electric shock applied to the floor were minimal in all animals. The results were discussed against a background of other olfactory system lesions and some evidence separating the effects of olfactory cues from nonolfactory lesion effects was presented. Finally, problems associated with tests for olfactory discrimination were discussed. A need for more rigorous and specific discrimination tests in behavioral studies involving anosmia was emphasized.

The Effect of Psychological Environment on Childbirth: Combined Cross -Cultural and Experimental Approach

A cross-cultural survey of birth patterning revealed marked differences in the speed of labor and indicated extreme variations in the psychological environment during labor and delivery. Speedier, easier labors appear to be related to acceptance of birth as a normal physiologic phenomena uncomplicated by sexual shame or fear-inducing rituals. The hypotheses developed from cross-cultural surveys were then tested experimentally in mice. Disturbance applied during labor resulted in reduction of labor speed immediately after the disturbance. Mice continuously disturbed at term delivered first pups significantly later, and had a 54% higher pup mortality rate. When expectant mice were rotated between familiar environment with shelter and glass fish bowl imbued with cat odor, spending equal amounts of time at each, significantly fewer births took place in the latter.