Figure 5.

Vi/Vc 5-HT₃receptor inhibition attenuates contralateral hyperalgesia. Inhibition of the 5-HT₃ receptor in the contralateral Vi/Vc attenuates CFA-induced contralateral hyperalgesia. CFA (0.05 ml; 1:1 oil/saline) was injected into the masseter muscle and 24 h later, Y-25130 was microinjected (0.5 μl) into the contralateral Vi/Vc (A, B). Y-25130 microinjection into the contralateral Vi/Vc attenuated contralateral hyperalgesia (A) but not ipsilateral hyperalgesia (B). Y-25130 microinjection into the ipsilateral Vi/Vc (C, D) did not attenuate ipsilateral or contralateral hyperalgesia. +: lowest dose vs. saline. #: middle dose vs. saline. *: highest dose vs. saline. +,#,*: p<;0.05; ++,##,**: p<;0.01; +++,###,***: p<;0.001 (ANOVA with repeated measures and Student Neuman-Keuls post-hoc test).