The NaK-adenosine triphosphatase (ATPase)-rich nerve-ending particle preparations (B fractions) of the epithelial tissue of chicken olfactory tubercle and the olfactory main concha were isolated by differential centrifugation. These tissues were exposed to the following odorants: 2-nonanone, 1-nonanol, 1-octanol, (+)2-octanol, and (-)2-octanol. There was a significant stimulation of NaK-ATPase by 2-nonanone (1 x 10(-3) M) in the B fraction of the olfactory tubercle and olfactory main concha. The NaK-ATPase increased significantly in the B fraction response of the olfactory main concha with 1 x 10(-3) M of 1-octanol but NaK-ATPase declined significantly in the presence of 1 x 10(-3) M of 1-nonanol. Both optical and structural isomers of odorants were shown to elicit different responses in NaK-ATPase activity. It is proposed that interactions between the odorant molecules and the membrane bound NaK-ATPase complex lead to recognition of odor by chickens.