Figure 4. Reversible heat-block of pulse propagation.
Heating of a worm above a critical temperature (average threshold temperature: 37.2±2.7°C; min: 33°C, max: 43°C; number of worms studied = 17) led to cessation of blood vessel pulsations. Regular contractions reappeared upon quick cooling. Illustrated is a typical temperature-frequency response as obtained from a single worm. Dashed lines are guides to the eye.