Effect of Hexamethonium Chloride on the Ciliary and Contractile Systems of the Ciliate Spirostomum

SYNOPSIS. The effect of hexamethonium chloride, an acetyl‐choline competitor, on the ciliary and myonemal systems of Spirostomum intermedium and S. ambiguum was investigated. Although the drug caused immobilization of the cilia, severe cell damage often ensued indicating an unspecific action. The general reaction was usually more severe and the ciliary inhibition less in S. ambiguum than in S. intermedium. It is postulated that the general reaction is the result of either membrane depolarization or binding of hexamethonium at the surface. Fed animals were more susceptible to drug action than starved ones. Raising the external potassium level did not affect the drug action.