CANINE OLFACTION 22/10/2012. Mobile plateforme -anatomy -physiology -environment -genetics. Detection Equipment

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1 CANINE OLFACTION Prof Dominique GRANDJEAN Unité de Médecine de l Elevage et du Sport Ecole Nationale Vétérinaire d Alfort (France) Vétérinaire Colonel Brigade de Sapeurs Pompiers de Paris Dr Delphine CLERO Unité de Médecine de l Elevage et du Sport Ecole Nationale Vétérinaire d Alfort (France) Vétérinaire Capitaine Brigade de Sapeurs Pompiers de Paris Mobile plateforme -anatomy -physiology -environment -genetics Detection Equipment 1

2 «Yes, but itdoesnot smelllikea bomb!» Genetic selection Respect of high motivation Physical training + Adapted nutrition = Optimization of performance Working dog Specific education Dedicated equipments Performance Housing and handling Biological and medical survey Physiological adaptations No Physiological specificities 2

3 Actual knowledge on dog s olfaction 1/ UPDATES IN DOG S OLFACTION PHYSIOLOGY 2/ HOW TO UNDERSTAND ODORS 3/ HOW TO OPTIMIZE OLFACTION IN THE DOG Physiology of Olfaction in the Dog «Sense individualising chemical species» Aptitude of the dog s olfactory system to individualise active molecules called odors by generating a specific Reaction of the animal. 3

4 Anatomyof the nosein the Dog Surface of olfaction membrane Humans Dogs Surface area of olfactory epithelium is 5 to 50x larger in dogs, as are number of olfactory receptors Kaldenbach,

5 TURBINATE BONES: MORE IN THE DOG THAN IN HUMANS (From Rosenbuch, 2009) 5

6 22/10/2012 Anatomy of the nose in the Dog Olfactory region Vestibule Nares Turbinates Nasopharynx (From Rosenbuch, 2009) Anatomy of the nose in the Dog Nose Functions (From Rosenbuch, 2009) 6

7 22/10/2012 Anatomy of the nose in the Dog 3 Histology (From Rosenbuch, 2009) Anatomy of the nose in the Dog Histology (From Rosenbuch, 2009) 7

8 Anatomyof the nosein the Dog Histology Olfactory epithelium Bowman s glands Nerve bundle 4 (From Rosenbuch, 2009) TURBINATE BONES: SURFACE AND AIR SPEED 8

9 IN AND OUT AIRFLOW DURING SNIFFING 9

10 NOTHING MUST IMPAIR AIRFLOW Experimental measurements of canine sniffing. Craven,

11 Experimental results from airflow measurements of canine sniffing. Craven, 2009 Labrador German Shepherd Medium Mongrel Pomeranian Physiology of Olfaction in the Dog Stimulus Odor 11

12 Olfactive Stimulus Volatil substances Access to olfactive mucosa Notion of «odority» of a molecule «A molecule is active on an olfactory system only if a correspondance exists between the particular structure of this molecule and a receptor-captor system in the mucosa.». Air volume. Atmosphere Pressure. Air Speed. Nature of the molecule (hydro or liposoluble) Olfactive Stimulus Chemical Molecules Al(OH) 3 Ca(OH) 2 H 2 CO 3 NH 2 (CH 2 )5NH 2 C 18 H 24 O 3 C 14 H 11 NC l2 O 2 12

13 Olfactive Stimulus That occupate a volume Olfactive Stimulus in 3 dimensions 13

14 Olfactive Stimulus «Pedagogic Approach» Chemical «Form» Aimof training : «Addict» the dog to a familyof moleculesthatactas «forms» in his mucosal receptors Olfactive Stimulus Dog s sniffing behaviour makes him«vizualise» the odors 14

15 Olfactive Stimulus Dog s sniffing behaviour makes him«vizualise» the odors Physiology of Olfaction in the Dog Stimulus Odor Receptor Cellular Site 15

16 Nasal biopsies provide the opportunity to examine the evolution of nasal mucosa (Overall, 2007) Details of olfactive mucosa Olfactive nerves Olfactory Marker Protein (Overall, 2007) 16

17 Details of olfactive mucosa Olfactive neurones Birth Immature and growing (Overall, 2007) Details of mature olfactive mucosa (Overall, 2007) 17

18 Olfactory Receptors Axones of olfactive nerves Olfactive Bulb Epithelium Olfactive cell Dendrites Olfactory Receptors Bipolar Neurones The only ones in the CNS to regenerate during the whole life cycle 18

19 Olfactive Receptors Receptorsfor odorant molecules are groupedin the cils 19

20 RECEPTORS MUCUS RECEPTORS 20

21 The amount of olfactive receptors varies depending on the breed Coren, 2004 CAMPHER MUSC FLOWER Olfactive Receptors Contact between the molecule and The receptor Amoore s stereochemical theory : 7 primary odors. Campher [spheric form 7 A]. Musc [discoid form 10 A]. Flower [wing form]. Menthol [corner form]. Eter [electrophile molecules ]. Cadaver [nucleophile molecules] CADAVER MENTHOL ETER SPICY 21

22 Olfactive Receptors Olfactive Receptors In 1991, Richard Axel and Linda Buck clonedthe first olfactive receptors. For this work, they obtained the Nobel price in physiology and medicine in

23 Olfactive Receptors mouse: 1000 gènes Genomics: how many genescode for olfaction zebrafish: 100gènes drosophilia: 57 gènes dog : 850 gènes GENOMICS OF OLFACTION (ACHE et YOUNG, 2005) : genes coding for olfactive receptors in different species. In red amount of genes, in blue amount of pseudo-genes. 23

24 Localization of canine OR genes CFA CFA (32) CFA CFA CFA (3) CFA (2) (1) (3) CFA (2) (3) 2 CFA 11 (3) 5 CFA CFA (4) +4 (16) +7 (18) 11 CFA CFA 23 CFA CFA (109) +1 (5) +3 (12) CFA CFA 32 4 CFA 38 1 CFA Y Y CFA X +6 (15) (6) +3 (9) CFA 17 3 CFA (3) CFA (7) (1) 16 CFA CFA 12 X CFA 3 CFA 4 +2 (3) CFA 8 CFA 9 (3) +5 (12) +4 (9) 6 CFA CFA 14 CFA (31) 7 1 (1) 7 11 CFA CFA CFA 24 CFA (21) +3 (8) +18 (44) (123) CFA CFA 30 (1) +4 (16) CFA CFA 36 2 CFA (9) RH1 RH2 RH (Gallibert, 2009) 30 regions (clusters) on 24 chromosomes out of 38 chromosomes (CFA) +2 (3) (2) (2) +6 (11) Differences occur between breeds 24