Cat odor causes long-lasting contextual fear conditioning and increased pituitary-adrenal activation, without modifying anxiety.
A single exposure to a cat or cat odors has been reported by some groups to induce contextual and auditory fear conditioning and long-lasting changes in anxiety-like behaviour, but there is no evidence for parallel changes in biological stress markers. In the present study we demonstrated in male rats that exposure to a novel environment containing a cloth impregnated with cat fur odor resulted in avoidance of the odor, lower levels of activity and higher pituitary-adrenal (PA) response as compared to those exposed to the novel environment containing a clean cloth, suggesting increased levels of stress in the former animals. When re-exposed 9 days later to the same environment with a clean cloth, previously cat fur exposed rats again showed avoidance of the cloth area and lower levels of activity, suggesting development of contextual fear conditioning, which again was associated with a higher PA activation. In contrast, unaltered both anxiety-like behaviour and PA responsiveness to an elevated plus-maze were found 7 days after cat odor exposure. It is concluded that: (i) PA activation is able to reflect both the stressful properties of cat fur odor and odor-induced contextual fear conditioning; (ii) development of cat odor-induced contextual fear conditioning is independent of the induction of long-lasting changes in anxiety-like behaviour; and (iii) greater PA activation during exposure to the odor context is not explained by non-specific sensitization of the PA axis caused by previous exposure to cat fur odor.
Muñoz-Abellán
Cristina
C
Institute of Neurosciences, Autonomous University of Barcelona, Bellaterra, Spain.
Daviu
Nuria
N
Rabasa
Cristina
C
Nadal
Roser
R
Armario
Antonio
A
D000324:Adrenocorticotropic Hormone / Q000097:blood; D000818:Animals; D001007:Anxiety / Q000503:physiopathology*; D001362:Avoidance Learning / Q000502:physiology; D002415:Cats; D003214:Conditioning, Classical / Q000502:physiology*; D003345:Corticosterone / Q000097:blood; D004777:Environment; D005239:Fear / Q000502:physiology*; D008297:Male; D018782:Maze Learning / Q000502:physiology; D009812:Odorants; D055696:Olfactory Perception / Q000502:physiology*; D010812:Physical Stimulation; D010913:Pituitary-Adrenal System / Q000502:physiology* / Q000503:physiopathology; D011897:Random Allocation; D051381:Rats; D017207:Rats, Sprague-Dawley; D013997:Time Factors
D000324:Adrenocorticotropic Hormone; D003345:Corticosterone