Psychobiological effects of perinatal exposure to odorants in mice. Part II: Behavioural alteration

Early exposure to odorants pre-, post- or transnatally is known to. result in a decreased avoidance or increased preference for these. odorants in mammals. There are also indications that olfactory sensitivity. for these odorants can be affected. We exposed C57-Bl/6. mice of Mor23-GFP and M71-GFP lines to lyral (LY) or acetophenone. (AC), respectively, either transnatally through the water of the. mother (1*10-5 M) or postnatally in air for 1 hr per day (20 ll pure). Animals were weaned on postnatal day 20 (P20), and 3 tests were. performed:. 1) A 3-min exploration test on P20 in a rectangular arena presenting. LY and AC under a wire mesh to measure the time spent in each. half of the arena. 2) A 2-bottle choice test on P21, whereby LY and AC-flavoured. water (1*10-5 M) was provided to assess intake. 3) An olfactory sensitivity test based on an habituation procedure. on P21 using two 2-min habituation trials with water and 6 dishabituation. trials whereby either LY (in concentrations ranging from. 9.77*10-9 to 1.0*10-5 M) or AC (9.54*10-7 to 1.0*10-5 M) was presented. to assess time spent exploring and number of visits to the. stimuli, assuming increased exploration when the odorant is perceived. Control animals of both lines displayed a preference for LY compared. to AC in the exploration test (LY: 99 vs. AC: 81 s, Mor23:. p=0.04, M71: p=0.03), while transnatal AC exposure resulted in. an absence of preference for either odorant (91 vs. 89 s) and postnatal. exposure in a higher preference for AC (78 vs. 108 s, p=0.02). In contrast,. LY exposure decreased preference for LY, both trans- and. E76 ECRO Abstracts. Downloaded from chemse.oxfordjournals.org at INIST-CNRS on February 28, 2011. postnatally exposed animals showing no preference for either odour. (transnatal: 89 vs. 91; postnatal: 86 vs. 94 s). We furthermore show results of 2-bottle choice test, and the. effects of LY and AC exposure on behavioural olfactory sensitivity. These results are linked with density of Mor23- and M71-receptorexpressing. olfactory sensory neurons which show high affinity to. LY and AC, respectively, presented in the poster by Tazir et al (Part. I). This research was supported by a doctoral grant from CNRSRegion. Burgundy, and by continued support from Region Burgundy.