Fig. 2

AMPAkine potentiation of the NAc partially reconstitutes the anti-nociceptive effects of PL. a Optogenetic activation of the PL has a greater impact than AMPAkine infusions into the NAc core on reducing sensory withdrawals on Hargreaves test. ChR2 group, n = 7; YFP group, n = 7; YFP + AMPAkine vs YFP + saline (*p = 0.0114); ChR2 + AMPAkine vs ChR2 + saline (p > 0.9999); ChR2 + AMPAkine vs YFP + AMPAkine (****p < 0.0001), ChR2 + saline vs YFP + saline (****p < 0.0001); Two-way ANOVA with repeated measures and Bonferroni’s multiple pair-wise comparisons. b Schematic of the CPP assay with optogenetic activation of the PL in the presence of noxious pin prick (PP) after AMPAkine or saline infusion into the NAc core. AMPAkine or saline was infused into the NAc 15 min prior to the CPP assay. During the CPP assay, one of the chambers was paired with optogenetic activation of the PL and PP; the other chamber was paired with PP alone. During the preconditioning or testing phase, no stimuli were given and rats were allowed free movement. c Control (saline-infused) rats, when presented with noxious stimuli (PP), preferred the chamber associated with optogenetic PL activation. n = 6, *p = 0.0101, paired Student’s t-test. d Control rats that had YFP injection did not demonstrate a preference for either chamber. n = 6, p = 0.5973, paired Student’s t-test. e CPP score for PL activation in the presence of noxious mechanical stimuli after saline infusion into the NAc core. n = 6, ^** p = 0.0098, unpaired Student’s t test. f Rats that received AMPAkine infusion prior to the CPP test, when presented with PP, did not demonstrate preference or aversion for the chamber associated with optogenetic PL activation. n = 6, p = 0.7524, paired Student’s t-test. g AMPAkine-infused rats that received YFP injection also demonstrated no preference or aversion for either chamber. n = 6, p = 0.1990, paired Student’s t-test. h After AMPAkine infusion into NAc core, the CPP score for PL activation was not increased compared with YFP control. n = 6, p = 0.5238, unpaired Student’s t test. i CPP scores indicate that AMPAkine treatment in the NAc eliminated the preference of chamber associated with PL activation. n = 6, **p = 0.0031, unpaired Student’s t test