THE ACTION OF CERTAIN DRUGS ON CRUSTACEAN MUSCLE

¹ From the Marine Biological Laboratory, Woods Hole, Mass., and the College of Medicine, Syracuse University

Irritability and contractility of crustacean striated muscle is increased by perfusion with solutions of epinephrine, post-pituitary, physostigmine, and by certain members of the ergot group. Stronger solutions cause slow contractions independent of electrical stimulation. Mechanically these contractions resemble contractions of vertebrate smooth muscles. Such contractions in normal muscle result from repetitive excitation.

Atropine and pilocarpine in strong solution, e.g. 1-500, cause depression after transient stimulation. The usual twitch disappears and is replaced by a small slow contraction. These effects are reversible.

No effect of acetylcholine could be demonstrated.

The only action of curare is to cause some increase of irritability.

The effects of nicotine varied, but in the majority of experiments there was slight stimulation.