Fig. 9.

Role of CC5 in the arterial-shortening component of a local withdrawal response. A, In a semi-intact preparation, touches (line under trace) to the tentacle with a piece of seaweed evoked firing of CC5 and contraction of the ipsilateral PA. For the last touch in the series, CC5 fired at a relatively low frequency, and only a small contraction was evoked.B, Effect of hyperpolarizing CC5 on the arterial contraction reflex. The tentacle was touched three times (B1–B3), and CC5 also was stimulated directly (B4). B1, When CC5 was at rest potential, a tactile stimulus evoked spikes in CC5, and an arterial contraction occurred. B2, When CC5 was hyperpolarized, the touch with seaweed evoked only a single spike in CC5, and there was no contraction of the artery. B3, Direct firing of CC5 at a rate comparable to that evoked by the tactile stimulus evoked a comparable contraction of the artery (n = 6).