Microinjections of SCH 23390 in the ventral tegmental area reduce operant responding under a progressive ratio schedule of food reinforcement in rats

Blockade of muscarinic acetylcholine receptors in the ventral tegmental area prevents acquisition of food-rewarded operant responding in rats

“…Dopamine (DA) is implicated in reward-related learning (Wise and Rompré 1989;Wise and Bozarth 1987;Berridge 1995;Wise 2004) and is thought to mediate the incentive motivational effects of reinforcers (Berridge and Robinson 1998;Ikemoto and Panksepp 1999;Wise 2004). Rewards can elevate extracellular DA concentrations in mesocorticolimbic and mesostriatal systems (Hernandez and Hoebel 1988;Bradberry and Roth 1989;Pettit and Justice 1989;Chen and Reith 1994;Ranaldi et al 1999), and DA neurotransmission in these pathways appears critical for their rewarding effects; reductions in DA neurotransmission in the nucleus accumbens (NAcc), medial prefrontal cortex (mPFC), ventral tegmental area (VTA), striatum, or substantia nigra reduce responding maintained by food Aberman et al 1998;SmithRoe and Kelley 2000;Baldwin et al 2002;Sharf et al 2005), cocaine (McGregor and Roberts 1993;Ranaldi and Wise 2001;Quinlan et al 2004), or VTA brain stimulation (Kurumiya and Nakajima 1988).…”

Microinjections of a dopamine D1 receptor antagonist into the ventral tegmental area block the expression of cocaine conditioned place preference in rats

“…Animals treated with bilateral injections of the D1 receptor antagonist, SCH 23390, directly into the VTA respond less for food reward under a progressive ratio (PR) schedule of reinforcement [39]. This reduction in break point is interpreted as a reduction in motivation for food, suggesting a reduction in food reward.…”

In the ventral tegmental area, G-proteins mediate progesterone’s actions at dopamine type 1 receptors for lordosis of rats and hamsters

“…VTA infusions of the D 1 antagonist SCH23390, but not vehicle, reduce break points for intravenous cocaine or food rewards (Ranaldi and Wise 2001;Sharf et al 2005). That SCH23390-treated rats stopped responding for cocaine or food sooner than controls suggests blockage of D 1 , in the VTA, decreases reward value.…”