Figure 2.

A, spike discharge in mechanosensitive neurons gradually increased with increasing forces of the von Frey hairs (from 0.7 to 2.7 mN). Asterisks mark significant increase of spike discharge compared to a 0.7 mN von Frey hair. Number of neurons are given in parentheses. Data were obtained from different ganglia probed with different von Frey hair forces. Recordings are from a mixed population of neurons. B, spike discharge increased with increased durations of intraganglionic volume injections; increasing the pulse duration from 200 to 400 ms significantly enhanced the spike discharge (significance marked by asterisks). Number of neurons are given in parentheses. Data were obtained from the same neurons which all responded to both 200 and 400 ms injections. C and D, reproducibility of the responses to mechanical stimulation by intraganglionic volume injections. Four consecutive stimulations (c1–c4) were applied every 15 min in 13 ganglia and responses from 85 neurons were analysed. The injection pipette remained in the same position. C shows that the number of responding neurons remained unchanged. D illustrates that the spike discharge of the 85 neurons remained stable along the four injection stimuli.