Piracetam and fish orientation during parabolic aircraft flight.

Goldfish were flown in parabolic Keplerian trajectories in a KC-135 aircraft to assay both the effectiveness of piracetam as an anti-motion sickness drug and the effectiveness of state-dependent training during periods of oscillating gravity levels. Single-frame analyses of infrared films were performed for two classes of responses--roll rates in hypogravity or hypogravity orienting responses (LGR) and climbing responses in hypergravity or hypergravity orienting responses (HGR). In Experiment I, preflight training with a vestibular stressor facilitated suppression of LGR by the 10th parabola. An inverse correlation was found between the magnitudes of LGR and HGR. Piracetam was not effective in a state-dependent design, but the drug did significantly increase HGR when injected into trained fish shortly before flight. In Experiment II, injections of saline, piracetam, and modifiers of gamma-aminobutyric acid (GABA)--aminooxyacetic acid (AOAA) and isonicotinic acid (INH)--did not modify LGR. AOAA did significantly increase HGR. Thus, the preflight training had a beneficial effect in reducing disorientation in the fish in weightlessness, but the drugs employed were ineffective.