Fig. 1.

(A) Intra-cellular sharp electrode recordings of membrane potential (top) and recordings of applied and generated force (bottom) in cat isolated sinoatrial node tissue, representative of recordings taken from rabbit in the same investigation, showing an increase in beating rate with stretch (contraction pointing upwards) and reduction in absolute values of maximum systolic and diastolic potentials (from (Deck, 1964), with permission). (B) Axial stretch by the carbon fibre technique of a spontaneously beating rabbit sinoatrial node cell (right; scale bar = 10 μm) and (C) simultaneous patch-clamp recordings of membrane potential showing an increase in beating rate, accompanied by a reduction in the absolute values of maximum diastolic and maximum systolic potentials (light curve = no stretch, dark curve = stretch; from (Cooper et al., 2000), with permission). (D) Whole-cell stretch-induced current-voltage relation (difference current in absence/presence of streptomycin to block SAC) from rabbit sinoatrial node cells showing a reversal potential of −11 mV (dotted lines = 95% confidence limits, I = current, V = voltage; from (Cooper et al., 2000), with permission).