Abramson and Gettner attempted to block the LSD surfacing reaction in goldfish by lowering the water pH. In a bowl at pH 5.0, only 30% of the fish demonstrated the fish surfacing reaction. When shifted to pH 5.8, nearly all of the fish began the surfacing reaction, thus demonstrating a pH-dependent effect (figure below).
The authors suspected that pH affects the absorption of LSD across the gills. They wrote:
“Alkaloids are not absorbed to any extent from the stomach when the reaction of the gastric juice is strongly acid. If the gastric juice is rendered alkaline, however, alkaloids are rapidly absorbed from the ligated stomach. It is of interest that absorption slows at about pH 5.0 and is fairly rapid at pH 6.0.” (Gettner,H.H. 1973)Using a different methodological approach, the researchers dipped goldfish for 30 seconds in an LSD-containing solution, and then placed them in normal tank water. Drug concentrations in the dipping tank ranged from 5 to 50 ug/mL LSD. About 70% of the fish that were briefly dunked still demonstrated the fish surfacing reaction, but recovered more quickly than fish who swam in LSD-containing water for many hours. The dotted lines in the figure below represent the die-away curves for fish that were dipped for 30 seconds only, which demonstrated that LSD can be rapidly absorbed by the animal body. The surfacing reaction was more persistent when fish were immersed in LSD solutions (solid black lines).
Similar curves were obtained by dipping goldfish for 30 seconds into solutions of methysergide.
Gettner H. H., P. A. Carone and H. A. Abramson (1973). Lysergic acid diethylamide (LSD 25). XXXX. Effect of pH on transport of methysergide and LSD 25 across gill membrane. The Journal of Psychology 84, 111-118.