Fig. 4. Ca²⁺transients elicited by single action potentials (APs) at 3-s intervals, recorded in neurons of intact ganglia. (A ) Typical recording of cytosolic Ca²⁺transients (left ) in a control C-type neuron elicited by conducted single APs. Each of the four APs produces a comparable Ca²⁺transient. Simultaneous recording of the membrane potential (right ) confirms the generation of a single AP. The arrow  indicates the artifact from dorsal root simulation. (B ) Summary data of cytosolic Ca²⁺transients produced by four sequential single APs in C-type neurons show no significant variation (amplitude: analysis of variance main effect P = 0.73, n = 39; decay constant: P = 0.17; n = 29). (C ) Typical cytosolic Ca²⁺transients and corresponding simultaneously recorded APs from an Aδ-type neuron (upper traces ) and an Aβ-type neuron (lower traces ) show smaller Ca²⁺transients. (D ) Summary data of Ca²⁺transients elicited by a single AP in different neuron types, and comparing control neurons and neurons injured by spinal nerve ligation. The effect of injury was compared in neurons of each type separately (t  test). Numbers in bars  indicate n; brackets connecting bars  indicate significant difference.