ENHANCEMENT OF THE TURTLE OLFACTORY RESPONSES TO FATTY-ACIDS BY TREATMENT OF OLFACTORY EPITHELIUM WITH PHOSPHATIDYLSERINE

The turtle olfactory epithelium was treated with suspensions of variou s lipids and their effects on the olfactory responses were examined by measuring the olfactory bulbar responses. The phosphatidylserine (PS) -treatment greatly lowered the threshold for n-valeric acid and enhanc ed its responses at all concentrations examined. The responses to isov aleric acid and n-butyric acid were also greatly enhanced by the PS-tr eatment. The responses to ten other odorants examined were a little en hanced or unchanged by the PS-treatment. The enhanced responses to the fatty acids returned to the original level about 10 h after the treat ment. It was confirmed that PS was incorporated into olfactory epithel ium by incubating the epithelium with PS-suspension containing [C-14]P S. The treatment of the epithelium with phosphatidic acid or cardiolip in unchanged or suppressed the responses to odorants including the fat ty acids. The present results suggest that lipids as well as proteins in the receptor membranes play an important role in odor reception.