Influence of a detergent on the catfish olfactory mucosa.

The olfactory mucosa of the catfish (Ictulurus punctatus) has been briefly exposed to various concentrations of the non-ionic detergent Triton X-100. At high concentrations (1-4%) the upper layer of cells constituting the sensory and non-sensory areas of the lamellae is extensively damaged and new receptor cells do not appear in significant number before 2 months after treatment. Respiratory cells regenerate first followed by sustentacular and olfactory receptors. The regenerative process is very similar to that described previously after prolonged contact between the mucosa and ZnSO4. Low detergent concentrations 0.03-0.1% affect only the sensory area. Olfactory and sustentacular microvilli and cilia, are immediately severed by the chemical. Regeneration occurs within the next 4 days. The cellular membranes appear also to be affected. From anatomical, electrophysiological and biochemical studies both in vivo and in vitro, it can be hypothesized that a receptors involved in the transduction process are solubilized by the detergent but reappear at a level corresponding to 50-60% of their original activity within 2 h. Proteins, having an amino acid binding effectiveness correlated to the amino acid electrophysiological activities measured in vivo, can be isolated from the solubilized material. Further studies will be necessary to confirm that some of these molecules are involved in the olfactory transduction mechanism.