and AcbSh, but not AcbCo.139 These findings support a role for ERK1/2 phosphorylation in the BLA and AcbSh in mediating cue-induced reinstatement of ethanol-seeking behavior. A third study from this laboratory141 confirmed a role for mGlu5 within the AcbCo in ethanol self-administration; such that local application of MPEP into the AcbCo reduced ethanol operant responding without affecting locomotor activity, sucrose or water responding. In contrast, MPEP infused into the dorsomedial caudate nucleus or mPFC did not alter operant ethanol self-administration.141 In a study that examined the effects of mGlu5 antagonist 3-[(2-methyl-1,3-tia-zol-4-yl)ethynyl]-pyridine (MTEP) on ethanol self-administration by two high alcohol–consuming rat lines (inbred P (iP) and Fawn-Hooded (FH)) reported that MTEP significantly decreased intake.142 However, these authors also reported that MTEP induced mild sedative effects in iP but not FH rats. Together, these findings indicate that mGlu5 receptors play an important role in regulating different aspects of alcoholism-related behavior in both rat and mouse models.
