Skip to main content
. 2003 Jun 19;139(8):1498–1504. doi: 10.1038/sj.bjp.0705378

Figure 5.

Figure 5

Effect of 5-HT1A receptor antagonists on fentanyl-induced decreases in extracellular 5-HT in the DRN. Mean baseline level of extracellular 5-HT was 4.7±0.6 pg sample−1 (n=32). The open horizontal bar indicates the period of fentanyl infusion (a) The arrow indicates (−)-pindolol injection (8 mg kg−1, s.c.). After pretreatment with (−)-pindolol, fentanyl infusion did not significantly affect 5-HT as compared to (−)-pindolol alone (F(1,9)=0.41, P=0.5390). (b) The arrow indicates naltrexone (10 mg kg−1, s.c.) injection. The stipled bar indicates the period of WAY-100635 (100 μM) infusion. There were significant differences between groups (F(2,18)=10.25, P=0.0011). For the WAY-100635 pretreatment group, fentanyl infusion induced a significant increase in 5-HT (F(1,13)=5.63, P=0.034; WAY-100635+fentanyl compared to WAY-100635+aCSF). This effect was blocked by naltrexone (F(1,12)=18.82, P=0.001; naltrexone+WAY-100635+fentanyl compared to WAY-100635+fentanyl). *P<0.05 WAY-100635+fentanyl vs WAY-100635+aCSF; +P<0.05 WAY-100635+fentanyl vs naltrexone+WAY-100635+fentanyl.