Figure 1.

Hyperalgesia and oedema induced by carrageenan in rat paws. The effects of three doses of carrageenan measured hourly for 4 h and then again at 24 h, following intraplantar injection are shown separately for hyperalgesia (a) and oedema (b), although both variables were measured in each animal. Hyperalgesia is represented by a decrease in the response threshold below the control value and is expressed as the weight (in g) at which the response was elicited. Oedema is shown as an increase in paw volume above control value. The means (±s.e.mean) values from groups of four rats for each condition are shown. For all doses of carrageenan, the nociceptive threshold was significantly less than that for control (saline injection) for 1–3 h and, for the two higher doses also at 4 h. Paw volume was significantly increased for all doses of carrageenan for all the times shown. *Significantly different from control; P<0.05.