Table 1.

Summary of experimental methods for inducing posterior sucker injury in Hirudo.

	Posterior Sucker cut	Posterior Sucker crush	Posterior Sucker LPS injection	Posterior Sucker pierce
Non-nociceptive sensitization	Yes (but see below)	Yes	Yes	Yes
Nociceptive sensitization	Yes	Yes (but see below)	No	Yes (transient)
Reason for rejection of injury method	• Level of non-nociceptive sensitization was highly variable day-to-day. • Extent of cut difficult to standardize	• Differences in injured vs. non-injured groups may have been due to an increase in the response latency in the non-injured (control) group	• No nociceptive sensitization • Non-nociceptive sensitization was not robust • Control-injected animals exhibited decrease in response threshold to von-Frey