Temperature dependence of phase response curves for drug-induced phase shifts

The effectiveness of drugs active in phase-shifting the circadian rhythm of bioluminescent glow in the unicellular dinoflagellate Gonyaulax polyedra differs, depending upon the time of drug exposure (as pulses). For two drugs tested--cycloheximide and anisomycin, both inhibitors of cytosolic protein synthesis--this function, referred to as the drug phase response curve (dPRC), differs, depending upon the ambient temperature. Since dPRCs may differ at different drug concentrations, the effects observed may be attributable to differences in the effectiveness of or recovery from the drugs at different temperatures.