The dopamine D3-receptor: A postsynaptic receptor inhibitory on rat locomotor activity

Behavioral sensitization, the progressive and enduring enhancement of certain behaviors following repetitive drug use, is mediated in part by dopaminergic pathways. Increased locomotor response to drug treatment, a sensitizable behavior, is modulated by an opposing balance of dopamine receptor subtypes, with D1/D2 dopamine receptor stimulation increasing and D3 dopamine receptor activation inhibiting amphetamine-induced locomotion. We hypothesize that tolerance of D3 receptor locomotor inhibition contributes to behavioral sensitization. In order to test the hypothesis that expression of behavioral sensitization results in part from release of D3 receptor-mediated inhibition, thereby resulting in decreased response to D3 receptor agonists, we examined the effect of repetitive amphetamine administration on the behavioral response to the D3 receptor preferring agonists 7-OH-DPAT and PD 128907. D3-selective effects have recently been described for both drugs at a low dose. At 1 week following completion of a repetitive treatment regimen, amphetamine-pretreated rats displayed a decreased response to D3-selective doses of both 7-OH-DPAT and PD 128907, when compared to animals receiving saline pretreatment. Moreover, in addition to the quantitative alteration in response, there was a change in the inter-relation between response to amphetamine and D3 agonist. A highly significant inverse relation between locomotor inhibitory response to PD 128907 and the locomotor-stimulant response to amphetamine was observed prior to amphetamine treatment. In contrast, 10 days following repetitive amphetamine treatment, the relation between response to PD 128907 and amphetamine was not detected. The observed behavioral alteration could not be accounted for by changes in D3 receptor binding in ventral striatum. These findings suggest a persistent release of D3 receptor-mediated inhibitory influence contributes to the expression of behavioral sensitization to amphetamine.

Section: Introductionmentioning

confidence: 75%

Altered Behavioral Response to Dopamine D3 Receptor Agonists 7-OH-DPAT and PD 128907 Following Repetitive Amphetamine Administration

Richtand

Welge

Levant

et al. 2003

“…On the contrary, a trend towards conditioned place avoidance (CPA) was observed, an effect also obtained at the same dose (1 mg/kg) by Gyertyán and Gál (2003), whereas, in mice, BP 897 was reported to induce neither CPP nor CPA (Francès et al, 2003). Preclamol, a partial agonist at D 2 autoreceptors, and the D 3 R antagonists, l-nafadotride (B10-fold selective for rat D 3 R over D 2 R, in vivo (Griffon et al, 1995)), U-99194A (B20-fold selective for D 3 R vs D 2 R expressed in CHO cells (Waters et al, 1993)), and SB-277011-A (4100-fold selective for rat D 3 R over D 2 R expressed in CHO cells (Reavill et al, 2000)), seem devoid of incentive properties (Chaperon and Thiébot, 1996;Kivastik et al, 1996;Boyce and Risinger, 2002;Vorel et al, 2002;Gyertyán and Gál, 2003). However, in other studies, U-99194A has been shown to support CPP (Kling-Petersen et al, 1995;Gyertyán and Gál, 2003).…”

Section: Discussionmentioning

confidence: 98%

Effects of a Dopamine D3 Receptor Ligand, BP 897, on Acquisition and Expression of Food-, Morphine-, and Cocaine-induced Conditioned Place Preference, and Food-seeking Behavior in Rats

Duarte

Lefebvre

Chaperon

et al. 2003

The present study addressed the role of dopaminergic D 3 receptors (D 3 R) in motivational processes in rats. The effects of the selective D 3 R partial agonist, BP 897 (0.25-1 mg/kg, i.p.), on the establishment and the expression of conditioned place preference (CPP) supported by food, morphine (4 mg/kg, s.c.), or cocaine (2 mg/kg, s.c.) were investigated using an unbiased, one-compartment, placeconditioning procedure. When administered alone, BP 897 (0.05-2 mg/kg, i.p.) did not support CPP; on the contrary, conditioned place avoidance (CPA) was observed at 1 mg/kg, suggesting that this dose of BP 897 could be perceived as aversive. When given before each cocaine injection during the conditioning phase, BP 897 (1 mg/kg) prevented the establishment of CPP, and a single administration of BP 897 (0.5 and 1 mg/kg) before the test session impaired the expression of cocaine CPP. In contrast, neither the establishment nor the expression of food-and morphine-CPP were significantly altered by BP 897 (up to 1 mg/kg), whereas the full but less selective D 3 /D 2 R agonists, 7-OH-DPAT (0.5-2 mg/kg, s.c.) and quinelorane (1 mg/kg, s.c.), prevented the acquisition of food CPP. In a within-session extinction schedule of lever pressing for food, BP 897 (0.06-2 mg/kg) was ineffective in potentiating response reinstatement induced by the noncontingent delivery of two food pellets, in contrast with quinelorane and 7-OH-DPAT where previous studies showed to be efficient in this respect (Duarte et al, 2003). These results indicate that BP 897 has no positive appetitive value on its own, and that a moderate degree of stimulation of D 3 R is not sufficient to modulate food-primed food-seeking behavior or alter incentive motivation for food, morphine, and/or their associated cues. However, D 3 R are likely involved in the perception of the rewarding value of cocaine and cocaine-paired cues. This suggests that the appetitive effects of cocaine are subserved by mechanisms different, at least in part, from those of morphine and food, and that D 3 R play a role only in the former.

“…These results corroborate and extend previous studies of psychostimulant effects in D3R KO mice. For example, D3R KO mice exhibit an enhanced locomotor response after cocaine administration (Carta et al, 2000) and D3R antagonists augment cocaine (Piercey et al, 1992) and amphetamine-stimulated locomotion (Waters et al, 1993;Pritchard et al, 2007). D3R KO mice also exhibit an increase in cocaine cue-conditioned hyperactivity and cocaine cueconditioned mice had increased levels of D3R mRNA in the nucleus accumbens compared to saline controls (Le Foll et al, 2002).…”

Section: Discussionmentioning

confidence: 99%

Contributions of Dopamine D1, D2, and D3 Receptor Subtypes to the Disruptive Effects of Cocaine on Prepulse Inhibition in Mice

Doherty

Masten

Powell

et al. 2007

Deficits in prepulse inhibition (PPI) of startle, an operational measure of sensorimotor gating, are characteristics of schizophrenia and related neuropsychiatric disorders. Previous studies in mice demonstrate a contribution of dopamine (DA) D 1 -family receptors in modulating PPI and DA D 2 receptors (D2R) in mediating the PPI-disruptive effects of amphetamine. To examine further the contributions of DA receptor subtypes in PPI, we used a combined pharmacological and genetic approach. In congenic C57BL/6 J wildtype mice, we tested whether the D1R antagonist SCH23390 or the D2/3R antagonist raclopride would attenuate the effects of the indirect DA agonist cocaine (40 mg/kg). Both the D1R and D2/3R antagonists attenuated the cocaine-induced PPI deficit. We also tested the effect of cocaine on PPI in wild-type and DA D1R, D2R, or D3R knockout mice. The cocaine-induced PPI deficit was influenced differently by the three DA receptor subtypes, being absent in D1R knockout mice, partially attenuated in D2R knockout mice, and exaggerated in D3R knockout mice. Thus, the D1R is necessary for the PPI-disruptive effects of cocaine, while the D2R partially contributes to these effects. Conversely, the D3R appears to inhibit the PPI-disruptive effects of cocaine. Uncovering neural mechanisms involved in PPI will further our understanding of substrates of sensorimotor gating and could lead to better therapeutics to treat complex cognitive disorders such as schizophrenia.