Figure 3

Contraction patterns of Tethya wilhelma during extracorporeal caffeine application (a - d): Projected area of four specimens of T. wilhelma before, during (grey background) and after caffeine application. Caffeine induced contractions in all experiments. A spasm-like pattern representing an extremely prolonged phase in contracted state was observed once (b; see additional file 2: Movie_S2.mov for the time-lapse movie of Fig. 3b). Long-term application resulted in an irregular contraction pattern in some cases (c, d; see additional file 3: Movie_S3.mov for the time-lapse movie of Fig. 3c). Filled arrowheads indicate the points in time when stock solutions of the substances were injected into the experimental reactor circulation system to reach final concentrations of 515 μM (a - c) and 257 μM (d) respectively. Open arrowheads indicate the wash out of the substance from the experimental reactor system.