Olfactory discrimination ability and brain expression of c-fos, Gir and Glut1 mRNA are altered in n-3 fatty acid-depleted rats.
The long-chain polyunsaturated n-3 fatty acids (n-3 PUFA), particularly docosahexaenoic acid (DHA), are abundantly present in the central nervous system and play an important role in cognitive functions such as learning and memory. We, therefore, investigated the effects of n-3 PUFA-depletion in rats (F2 generation) on the learning of an olfactory discrimination task, progressively acquired within a four-arm maze, and on the mRNA expression of some candidate genes, i.e., c-fos, Gir and glucose transporter (Glut1), which could reflect the level of cerebral activity. We observed that DHA contents were dramatically decreased in the olfactory bulb, the piriform cortex and the neocortex of n-3-depleted rats. Furthermore, the n-3 deficiency resulted in a mild olfactory learning impairment as these rats required more days to master the olfactory task compared to control rats. Real-time RT-PCR experiments revealed that the training induced the expression of c-fos mRNA in all the three regions of the brain whereas Gir and Glut1 mRNA were induced only in olfactory bulb and neocortex. However, such an increase was less marked in the n-3-deficient rats. Taken together, these results allow us to assume that the behavioural impairment in n-3-deficient rats is linked to the depletion of n-3 fatty acids in brain regions processing olfactory cues. Data are discussed in view of the possible role of some of these genes in learning-induced neuronal olfactory plasticity.
Hichami
Aziz
A
UPRES EA 4183 Lipides & Signalisation Cellulaire, Université de Bourgogne, Faculté des Sciences de la Vie, Dijon, France.
Datiche
Frédérique
F
Ullah
Sana
S
Liénard
Fabienne
F
Chardigny
Jean-Michel
JM
Cattarelli
Martine
M
Khan
Naim Akhtar
NA
D000704:Analysis of Variance; D000818:Animals; D001522:Behavior, Animal / Q000502:physiology; D001835:Body Weight / Q000502:physiology; D001921:Brain / Q000378:metabolism*; D018752:Diet, Fat-Restricted / Q000379:methods; D004193:Discrimination Learning / Q000502:physiology; D004192:Discrimination, Psychological / Q000502:physiology*; D015525:Fatty Acids, Omega-3 / Q000378:metabolism*; D005786:Gene Expression Regulation / Q000502:physiology; D051272:Glucose Transporter Type 1 / Q000235:genetics* / Q000378:metabolism; D008297:Male; D016760:Proto-Oncogene Proteins c-fos / Q000235:genetics* / Q000378:metabolism; D012333:RNA, Messenger / Q000378:metabolism; D051381:Rats; D017208:Rats, Wistar; D043562:Receptors, G-Protein-Coupled / Q000235:genetics* / Q000378:metabolism; D020133:Reverse Transcriptase Polymerase Chain Reaction / Q000379:methods; D012903:Smell / Q000502:physiology*; D013997:Time Factors
D015525:Fatty Acids, Omega-3; D051272:Glucose Transporter Type 1; C501985:Gpr83 protein, rat; D016760:Proto-Oncogene Proteins c-fos; D012333:RNA, Messenger; D043562:Receptors, G-Protein-Coupled; C495679:Slc2a1 protein, rat