Fig. 3

The antinociceptive effects of i.c.v. CRF and CRF-R1 agonist stressin I and their antagonism by the opioid receptor antagonist naloxone in rats with inflamed hindpaws. The effects of i.c.v. co-administration of the opioid receptor antagonist naloxone with CRF or CRF-R1 agonist stressin I on nociceptive thresholds were measured by algesiometer. A The i.c.v. CRF’s induced-antinociception was significantly reduced by co-administration of the opioid receptor antagonist naloxone (F_{(5, 30)} = 384.8; P < 0.001). B Similarly, the antinociception resulting from i.c.v. CRF-R1 agonist stressin I was significantly attenuated by co-administered opioid receptor antagonist naloxone (F_{(5, 30)} = 400.8; P < 0.001) *indicates significant differences from vehicle treatment); data points (n = 6) represent means ± SD