Anesthetic antagonism of the effects of high hydrostatic pressure on locomotory activity of the brine shrimp Artemia

1. 1. The locomotory activity of small groups of brine shrimp ( Artemia salina) was studied under conditions of high hydrostatic pressure, varying temperatures and exposure to several gaseous anesthetics. 2. 2. Both compression and exposure to anesthesia reduced the animal's swimming activity, while temperature increased or decreased activity as it was raised or lowered from ambient. 3. 3. The effect of the anesthetics was less during periods of simultaneous exposure to high hydrostatic pressure. 4. 4. It is concluded that pressure antagonism of anesthesia is demonstrable in invertebrate organisms and may represent a fundamental interaction of these parameters in biological systems.