Melatonin and thyroxine: Influence on compass orientation in salamanders

摘要: Tiger salamanders (Ambystoma tigrinum) trained as larvae to orient in a particular compass direction reverse their of movement approximately at metamorphosis, but the timing reversal is not closely related developmental stage. Although exogenous thyroxine facilitates it does simultaneously trigger (Fig. 1). The occurs even if animals are deprived continuous view sky. Administration pulses melatonin noon, serotonin or thyroxine, caused shift directional response about 90° clockwise (Figs. 2, 3). This result consistent with that mimic “lights-on” and act phase-delay animal's endogenous timekeeping mechanism.