Predator odor exposure in early adolescence influences the effects of the bacterial product, propionic acid, on anxiety, sensorimotor gating, and acoustic startle response in male rats in later adolescence and adulthood

Deanne Tak On Wah; Klaus-Peter Ossenkopp; Indra Bishnoi; Martin Kavaliers

doi:10.1016/j.physbeh.2018.11.003

Predator odor exposure in early adolescence influences the effects of the bacterial product, propionic acid, on anxiety, sensorimotor gating, and acoustic startle response in male rats in later adolescence and adulthood

Physiol Behav. 2019 Feb 1:199:35-46. doi: 10.1016/j.physbeh.2018.11.003. Epub 2018 Nov 5.

Authors

Deanne Tak On Wah¹, Klaus-Peter Ossenkopp², Indra Bishnoi³, Martin Kavaliers⁴

Affiliations

¹ Department of Psychology, University of Western Ontario, London, Ontario, Canada.
² Department of Psychology, University of Western Ontario, London, Ontario, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada.
³ Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada.
⁴ Department of Psychology, University of Western Ontario, London, Ontario, Canada; Graduate Program in Neuroscience, University of Western Ontario, London, Ontario, Canada; Department of Psychology and Neuroscience Program, University of Guelph, Guelph, Ontario, Canada. Electronic address: kavalier@uwo.ca.

PMID: 30408471
DOI: 10.1016/j.physbeh.2018.11.003

Abstract

It is becoming evident than the adolescent period is a sensitive period in stress response programming. Stressors during this time may alter signaling from the gut microbiome, which has been shown to increase the risk for psychiatric disorders. It was hypothesized that adolescent stressors may potentiate the symptoms of anxiety and sensory abnormalities induced by a gut bacterial product, the short-chain fatty acid, propionic acid (PPA). The present study investigated the effects of repeated predator odor exposure during early adolescence on male rats administered PPA in late adolescence and adulthood on a behavioral test battery. Male adolescent Long-Evans rats were repeatedly exposed to a worn or unworn cat collar stimulus in early adolescence on postnatal days (P) 28, P30, P32, and P34. They were administered either PPA (500 mg/kg i.p.), or its vehicle in late adolescence on P40 and P43, and were subsequently tested on the light-dark anxiety task and acoustic startle task, respectively. In adulthood, the rats were again injected with PPA or its vehicle on P74 and P77, and subsequently tested on the light-dark apparatus and acoustic startle task, respectively. The repeated predator odor exposure was aversive and produced long-term anxiogenic effects as measured by the light-dark apparatus. PPA decreased activity and percent prepulse inhibition of the acoustic startle response, with its effects on vertical activity, a putative measure of escape behavior, being potentiated by prior predator stress. PPA's effects in adulthood were diminished in comparison to adolescence. These results suggest the importance of evaluating the effects of early adolescent stress on subsequent environmental insults on the development of behavioral abnormalities.

Keywords: Development; Locomotor activity; Prepulse inhibition; Sensory sensitivity; Short chain fatty acid; Stress.

Publication types

Research Support, Non-U.S. Gov't

MeSH terms

Acoustic Stimulation
Animals
Behavior, Animal / drug effects*
Male
Motor Activity / drug effects
Odorants
Predatory Behavior
Propionates / pharmacology*
Rats
Rats, Long-Evans
Reflex, Startle / drug effects*
Sensory Gating / drug effects*
Stress, Psychological*

Substances

Propionates
propionic acid