Influence of Narcotics on Ciliary Movement of the Gill of the Oyster.

Abstract

Ciliary activity is the simplest as well as the most widespread form of specialized contractile activity. The study of its physico-chemical conditions is therefore of fundamental interest in relation to the general problem of the conditions of mechanical action in protoplasm. There have been, however, as yet relatively few quantitative studies in this field. One reason for this is the difficulty of exact measurement. In the ciliated epithelium of metazoa the movement is not integrated (as it is in muscular contraction). Each ciliated cell is automatic and independent in its activity, although the direction of effective stroke is typically constant and there is some transmission between neighboring cells. Nervous control is absent or difficult to demonstrate, although it has been observed in certain invertebrates (e. g., veliger of nudibranchs as shown recently by Carter 1 ). Control, reversal, and inhibition are best developed in the ciliate Protozoa; electrical sensitivity is also shown most clearly in this group (electrotaxis of Paramoecium, etc.). The cilia of Protozoa are, however, less favorable for studies of narcosis than cilia of a more automatic type, such as those of the ciliated epithelium of metazoa.

In the present study we have chosen cilia having a high degree of persistence, regularity, and automaticity in their movement, namely the cilia of the gill of the oyster, Ostrea virginiana. The gill was removed along the gill axis, and then teased into small pieces of about 3 to 5 mm. in width. There are different kinds of cilia in the gill, but the cilia along the ventral margin of the gill were exclusively used. Movement of these cilia can more easily be observed from the side. Five such pieces of gill were placed in each of a series of glass vessels which contained 20 cc. of narcotic solutions of different concentrations in sea water. The vessel, which contained a sufficient free air space for oxygen supply, was covered and sealed with vaseline to prevent escape of narcotic vapor.