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1.
Peng Zhong Wei Wang Fei Yu Maressa Nazari Xiaojie Liu Qing-Song Liu 《Neuropsychopharmacology》2012,37(11):2377-2387
Endocannabinoid-mediated long-term depression of inhibitory synaptic transmission (I-LTD) in the ventral tegmental area (VTA) is implicated in cocaine-induced inhibitory synaptic plasticity and behavioral effects. It remains poorly understood, however, how this I-LTD is regulated and whether this regulation affects cocaine-seeking behavior. I-LTD requires cyclic adenosine 3′, 5′-monophosphate (cAMP)-dependent protein kinase A (PKA) signaling, raising the possibility that modulators of cAMP/PKA signaling may regulate I-LTD and the reinforcement behavior. Phosphodiesterase (PDE) 4 hydrolyses cAMP and terminates cAMP/PKA signaling. Here, we report that selective PDE4 inhibitors rolipram and Ro 20-1724 blocked I-LTD and acute depression of inhibitory postsynaptic currents (IPSCs) induced by D2 dopamine receptor and cannabinoid CB1 receptor agonists in VTA dopamine neurons. We also show that intra-VTA microinjections of PDE4 inhibitor rolipram impaired the acquisition, but not the expression, of conditioned place preference (CPP) to cocaine. Systemic administration of rolipram also increased cAMP response element-binding protein (CREB) phosphorylation and activation in the VTA. Together, our results suggest that blockade of cocaine-induced inhibitory synaptic plasticity (I-LTD) and enhancement of CREB activation are two putative cellular mechanisms by which PDE4 inhibition impairs the acquisition of cocaine CPP. 相似文献
2.
HISASHI KURIBARA YOSHITAKA UCHIHASHI 《The Journal of pharmacy and pharmacology》1993,45(12):1042-1045
Abstract— The repeated subcutaneous administration of methamphetamine (2 mg kg?1) and cocaine (10 mg kg?1) at 3–4 day intervals induced sensitization to their ambulation-increasing effects in mice. Subcutaneous administration of SCH 23390 (R-(+)-7-chloro-8-hydroxy-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine; 0·003–0·03 mg kg?1) and YM-09151–2 (cis-N-(1-benzyl-2-methylpyrrolidin-3-yl)-5-chloro-2-methoxy-4-methylaminobenzamide; 0·003–0·03 mg kg?1), the selective dopamine D1 and D2 antagonists, respectively, reduced dose-dependently the acute ambulation-increasing effect of methamphetamine. The development of methamphetamine sensitization was inhibited when it was administered in combination with either SCH 23390 or YM-09151–2 in the repeated administration schedule. Although SCH 23390 (0·01–0·1 mg kg?1) and YM-09151–2 (0·01–0·1 mg kg?1) also reduced the ambulation-increasing effect of cocaine (10 mg kg?1), neither drug inhibited the cocaine sensitization. Mice given cocaine with SCH 23390 (0·03 mg kg?1) or YM-09151–2 (0·03 and 0·1 mg kg?1) showed higher sensitivity than those given cocaine alone. The present results suggest that, although both the dopamine D1 and D2 antagonists reduce the acute stimulant effects of both methamphetamine and cocaine, they are only effective for inhibition of the methamphetamine sensitization. Mechanisms other than the dopaminergic system appear to be involved in the cocaine sensitization. 相似文献
3.
Rationale Previous studies have found a role for dopamine D2-like receptors in many of the behavioral effects of cocaine, including its stimulation of locomotor activity and interoceptive
discriminative-stimulus effects. However, given the lack of selectivity of most of the available pharmacological tools among
D2, D3 and D4 dopamine receptors, the roles of these specific receptors remain unclear.
Objectives The roles of specific dopamine D4 receptors in the behavioral effects of cocaine, including its locomotor stimulant and interoceptive discriminative-stimulus
effects were investigated using dopamine D4 receptor knockout (DA D4R KO) and wild-type (WT) mice.
Methods The mice were trained in daily sessions to discriminate IP injections of saline from cocaine (10 mg/kg). Responses on one
of two response keys intermittently produced a food pellet; one response was reinforced in sessions following cocaine injection
(10 mg/kg), and the other response was reinforced in sessions following saline injection. Each 20th response produced a food
pellet (fixed-ratio, or FR20 schedule of reinforcement). The dose-effects of cocaine and its interaction with the D2-like antagonist, raclopride, were assessed. Horizontal locomotor activity was also assessed in each genotype.
Results As previously shown), cocaine was a more potent stimulant of locomotor activity in the DA D4R KO mice compared to WT littermate mice. In addition, cocaine was more potent in producing discriminative-stimulus effects
in DA D4R KO mice (ED50 value=0.50 mg/kg) compared to their WT littermates (ED50 value=2.6 mg/kg). Raclopride shifted the cocaine dose-effect curve in both DA D4R KO and WT mice, though the shift was greater for the DA D4R KO mice.
Conclusions The present results on the stimulation of activity and interoceptive/subjective effects of cocaine are consistent with the
previously reported disregulation of dopamine synthesis in DA D4R KO mice, and further suggest a role of the DA D4R in vulnerability to stimulant abuse. 相似文献
4.
The objective of this study was to determine whether the development of behavioral sensitization to cocaine could be prevented by either D1 or D2 selective dopamine receptor antagonists. Male Wistar rats were treated daily for 7 days with either cocaine (15 mg/kg, IP) or vehicle in combination with the D1 dopamine antagonist SCH 23390 (0.3 mg/kg, SC), the D2 dopamine antagonist sulpiride (100 mg/kg, IP), or vehicle. After the daily injections, the rats were tested for locomotor activity in photocell arenas. Twenty-four hours after the last pre-exposure test session, all rats were given a challenge injection of cocaine (15 mg/kg, IP) and tested for activity. Cocaine treatments produced a greater relative increase in locomotor activity with repeated exposure (i.e. sensitization). Moreover, this increase in cocaine-induced locomotor activity was attenuated by both SCH 23390 and sulpiride. In contrast, neither sulpiride nor SCH 23390 blocked the development of behavioral sensitization to cocaine. That is, rats pretreated with sulpiride or SCH 23390 and cocaine did not differ from rats pre-exposed only to cocaine when given a cocaine challenge injection. These results suggest that behavioral sensitization to cocaine may develop through either D1 or D2 dopamine receptor stimulation or possibly through stimulation of some non-dopaminergic receptor.Portions of this paper were presented at the 1992 Society for Neuroscience meetings, Anaheim, Cal., USA 相似文献
5.
The present study examined the effects of receptor subtype-selective dopamine agonists and antagonists on (i) cocaine-induced responding for a cocaine-associated stimulus and (ii) on responding for food and cocaine reinforcement. Rats implanted with intravenous catheters were trained to lever-press for food or cocaine reinforcers on an FR5-FR5 multiple schedule, which was preceded by a 5-min component during which only stimuli previously associated with the primary reinforcers were available response-contingently. (i) Non-contingent delivery of cocaine at the beginning of the stimulus component significantly increased responding for the cocaine-associated stimulus, compared to responding for the food-associated cue. Changes in the dose of cocaine administered non-contingently before the stimulus component resulted in an inverted U-shaped dose-effect curve in responding for the cocaine-associated cue. In subsequent experiments, pretreatment with the dopamine D2 receptor agonist bromocriptine (4.0–16.0 mg/kg IP) attenuated the cocaine-induced increase in responding for the cocaine-associated cue. In contrast, pretreatment with low doses of SDZ 208–911, a dopamine D2 partial agonist (0.025–0.1 mg/kg SC), further potentiated the cocaine-induced response. Pretreatment with low and medium doses of the dopamine D1 and D2 receptor subtype-selective antagonists SCH 23390 (D1; 5–10 µg/kg SC) and raclopride (D2; 100–200 µg/kg SC) blocked responding for cocaine-associated cues, with SCH 23390 acting more selectively than raclopride. At higher doses (SCH 23390: 20 µg/kg SC; raclopride: 400 µg/kg SC), both drugs produced nonselective effects by inhibiting responses for the food-associated cue. (ii) Varying the dose of cocaine self-administered during the multiple schedule resulted in an inverted U-shaped dose-effect curve during the cocaine components, while the number of food pellets earned remained unchanged. Pretreatment with bromocriptine selectively reduced the number of cocaine infusions obtained. The compensatory increases in responding for cocaine typically associated with SCH 23390, raclopride or SDZ 208–911 pretreatment were also observed under the present schedule conditions, although the effect did not reach statistical significance in the case of SCH 23390 and raclopride, possibly due to methodological constraints. The results indicate that the present rat model of cocaine-seeking behavior is sensitive to pharmacological manipulations and may yield important information regarding the neurobiological mechanisms underlying conditioned and unconditioned reinforcing aspects of cocaine addiction. 相似文献
6.
Doris E Payer Arian Behzadi Stephen J Kish Sylvain Houle Alan A Wilson Pablo M Rusjan Junchao Tong Peter Selby Tony P George Tina McCluskey Isabelle Boileau 《Neuropsychopharmacology》2014,39(2):321-328
The dopamine system is a primary treatment target for cocaine dependence (CD), but research on dopaminergic abnormalities (eg, D2 receptor system deficiencies) has so far failed to translate into effective treatment strategies. The D3 receptor system has recently attracted considerable clinical interest, and D3 antagonism is now under investigation as a novel avenue for addiction treatment. The objective here was to evaluate the status and behavioral relevance of the D3 receptor system in CD, using the positron emission tomography (PET) radiotracer [11C]-(+)-PHNO. Fifteen CD subjects (many actively using, but all abstinent 7–240 days on scan day) and fifteen matched healthy control (HC) subjects completed two PET scans: one with [11C]-(+)-PHNO to assess D3 receptor binding (BPND; calculated regionally using the simplified reference tissue model), and for comparison, a second scan with [11C]raclopride to assess D2/3 binding. CD subjects also completed a behavioral battery to characterize the addiction behavioral phenotype. CD subjects showed higher [11C]-(+)-PHNO BPND than HC in the substantia nigra, which correlated with behavioral impulsiveness and risky decision making. In contrast, [11C]raclopride BPND was lower across the striatum in CD, consistent with previous literature in ⩾2 week abstinence. The data suggest that in contrast to a D2 deficiency, CD individuals may have heightened D3 receptor levels, which could contribute to addiction-relevant traits. D3 upregulation is emerging as a biomarker in preclinical models of addiction, and human PET studies of this receptor system can help guide novel pharmacological strategies for treatment. 相似文献
7.
Harmati G Bányász T Bárándi L Szentandrássy N Horváth B Szabó G Szentmiklósi JA Szénási G Nánási PP Magyar J 《British journal of pharmacology》2011,162(4):890-896
BACKGROUND AND PURPOSE
While the slow delayed rectifier K+ current (IKs) is known to be enhanced by the stimulation of β-adrenoceptors in several mammalian species, phosphorylation-dependent regulation of the rapid delayed rectifier K+ current (IKr) is controversial.EXPERIMENTAL APPROACH
In the present study, therefore, the effect of isoprenaline (ISO), activators and inhibitors of the protein kinase A (PKA) pathway on IKr and IKs was studied in canine ventricular myocytes using the whole cell patch clamp technique.KEY RESULTS
IKr was significantly increased (by 30–50%) following superfusion with ISO, forskolin or intracellular application of PKA activator cAMP analogues (cAMP, 8-Br-cAMP, 6-Bnz-cAMP). Inhibition of PKA by Rp-8-Br-cAMP had no effect on baseline IKr. The stimulating effect of ISO on IKr was completely inhibited by selective β1-adrenoceptor antagonists (metoprolol and CGP-20712A), by the PKA inhibitor Rp-8-Br-cAMP and by the PKA activator cAMP analogues, but not by the EPAC activator 8-pCPT-2''-O-Me-cAMP. In comparison, IKs was increased threefold by the activation of PKA (by ISO or 8-Br-cAMP), and strongly reduced by the PKA inhibitor Rp-8-Br-cAMP. The ISO-induced enhancement of IKs was decreased by Rp-8-Br-cAMP and completely inhibited by 8-Br-cAMP.CONCLUSIONS AND IMPLICATIONS
The results indicate that the stimulation of β1-adrenoceptors increases IKr, similar to IKs, via the activation of PKA in canine ventricular cells. 相似文献8.
Luca Ferraro Malgorzata Frankowska Daniel Marcellino Magdalena Zaniewska Sarah Beggiato Malgorzata Filip Maria Cristina Tomasini Tiziana Antonelli Sergio Tanganelli Kjell Fuxe 《Neuropsychopharmacology》2012,37(8):1856-1866
Recent in vitro results suggest that cocaine may exert direct and/or indirect allosteric enhancing actions at dopamine (DA) D2 receptors (D2Rs). In the present paper we tested the hypothesis that cocaine in vivo can enhance the effects of the D2-likeR agonist quinpirole in rats by using microdialysis and pharmacological behavioral studies. Furthermore, in vitro D2-likeR binding characteristics and Gαi/o-protein coupling, in the absence and in the presence of cocaine, have been investigated in rat striatal membranes. Intra-nucleus accumbens perfusion of the D2-likeR agonist quinpirole (10 μM) reduced local dialysate glutamate levels, whereas cocaine (10 and 100 nM) was ineffective. At a low concentration (100 nM), cocaine significantly enhanced quinpirole-induced reduction of accumbal extracellular glutamate levels. The behavioral experiments showed that cocaine (0.625 mg/kg), but not the DA uptake blocker GBR 12783 (1.25 mg/kg), enhanced quinpirole (1 mg/kg)-induced hyperlocomotion. Finally, cocaine (100 nM), but not GBR 12783 (200 nM), produced a small, but significant increase in the efficacy of DA to stimulate binding of GTPγS to striatal D2-likeRs, whereas the D2-likeR binding characteristics were unchanged in striatal membranes by cocaine in the nM range. The significant increase in the maximal response to DA-stimulated GTPγS binding to D2-likeRs by 100 nM cocaine remained in the presence of GBR 12783. The observed cocaine-induced enhancement of the Gαi/o-protein coupling of D2Rs may be in part because of allosteric direct and/or indirect enhancing effects of cocaine at these receptors. These novel actions of cocaine may have relevance for understanding the actions of cocaine upon accumbal DA, and/or glutamate transmission and thus its rewarding as well as relapsing effects. 相似文献
9.
Clozapine (3.8–60.0 µmol kg?1) did not produce any alterations in DOPA accumulation (following inhibition of cerebral aromaticl-amino acid decarboxylase) in the prefrontal cortex or in three regions of the neostriatum, i.e. the ventral, the dorso-lateral and the posterior regions, in the rat. In contrast, clozapine produced a reduction in the 5-HTP accumulation in all these brain areas, except for the prefrontal cortex. Raclopride (0.08–20.0 µmol kg?1) produced a marked increase in DOPA accumulation in all four brain regions and an increase in 5-HTP accumulation in the dorso-lateral neostriatum (2.5–20.0 µmol kg?1), but not in the other forebrain regions. Treatment with SCH-23390 (0.4–1.6 µmol kg?1) resulted in increased DOPA accumulation in the ventral and posterior parts of the neostriatum. No other changes in the DOPA or 5-HTP accumulation were seen with SCH-23390. Considering the doses of these three compounds needed for suppression of conditioned avoidance behavior and for the induction of cataleptic rigidity, it is concluded that raclopride produces an increased DA synthesis at much lower doses than those needed for behavioral effects. In contrast, the behavioral effects of SCH-23390 or clozapine precedes effects on brain DA synthesis on the dose-effect curve. In fact, the only biochemical effect of clozapine, which was observed in low, yet behaviorally active doses, was a decrease in forebrain 5-HTP accumulation. In conclusion, the present results demonstrate a mismatch, in different directions for raclopride and SCH-23390, as regards the doses needed to produce effects on brain dopamine synthesis and on behavior. Thus, the biochemical effects are seen with lower doses than the behavioral effects for the DA D2 receptor blocking agent, whereas the opposite relationship is the case for the DA D1 receptor antagonist. Taking these two DA receptor subtypes into consideration, the possibility should be considered that clozapine produces its antipsychotic-like behavioral effects on animal behavior primarily by a blockade of brain DA D1, rather than D2, receptors. 相似文献
10.
Haag S Warnken M Juergens UR Racké K 《Naunyn-Schmiedeberg's archives of pharmacology》2008,378(6):617-630
In lung fibroblasts, proliferation is inhibited by activation of EP2 prostanoid receptors which are known to couple to adenylyl cyclase. Beside the classic target of cAMP, protein kinase A (PKA),
alternative cAMP effectors have been identified, among them Epac (exchange protein activated by cAMP). The present study aimed
to illuminate transduction pathways mediating the anti-proliferative effects of EP2 receptors in lung fibroblasts. Proliferative activity of human lung fibroblasts was determined by measuring [3H]-thymidine incorporation. The selective EP2 receptor agonist butaprost inhibited [3H]-thymidine incorporation by 75%, an effect mimicked by forskolin, the phosphodiesterase inhibitor IBMX, the stable cAMP
analogues dibutyryl-cAMP and bromo-cAMP, as well as by the Epac selective cAMP analogues 8-pCPT-2′-O-Me-cAMP and Sp-8-pCPT-2′-O-Me-cAMPS, whereas the PKA selective agonist 6-Bnz-cAMP was inactive. The PKA inhibitor Rp-8-Br-cAMPS inhibited butaprost-induced
phosphorylation of CREB (cAMP response element-binding protein), but did not affect butaprost-induced inhibition of [3H]-thymidine incorporation. Partial knockdown of Epac1 by specific siRNA transfection resulted in a marked attenuation of
the inhibitory potency of butaprost, whereas transfection of Epac2 siRNA or non-silencing siRNA did not affect the effectiveness
of butaprost to inhibit [3H]-thymidine incorporation. In conclusion, Epac1 rather than the classic cAMP effector PKA is a crucial element in the signal
transduction pathway mediating anti-proliferative effects of EP2 receptor activation. 相似文献
11.
Lars Farde 《Psychopharmacology》1992,107(1):23-29
Pharmacological effects were recorded and time course for receptor binding in brain was followed by positron emission tomography after IV injection of the selective D1-dopamine receptor antagonist SCH 23390 in four healthy subjects in doses of 310–810 µg. Akathisia, the syndrome of motor restlessness, appeared after the three highest doses. The akathisia was transient and occurred only when [11C]SCH 23390 binding in the basal ganglia was at a high level with a central D1-dopamine receptor occupancy of 45–59%. The D2-dopamine receptor antagonist [11C]raclopride was injected IV into 20 healthy subjects and 13 schizophrenic patients. Akathisia appeared in 14 healthy subjects and 7 patients and coincided with maximal [11C]raclopride binding in the basal ganglia. The findings for [11C]raclopride and [11C]SCH 23390 are the first demonstration of a relationship between time courses for radioligand binding in the human brain and simultaneously induced pharmacological effects. 相似文献
12.
We have previously reported that two D1 dopamine agonists, SKF 82958 and SKF 77434, are readily self-administered by rats. However, due to the limited selectivities of these agents, it was not possible to attribute their reinforcing effects exclusively to their D1 actions. To assess the relative involvement of D1 and D2 receptors in SKF 82958 reinforcement, rats were pretreated 30 min before self-administration sessions with either the D1-selective antagonist (+)SCH 23390 or the D2-selective antagonist raclopride. The D1 antagonist (+)SCH 23390 (5–20 µg/kg, SC) produced significant, dose-related (compensatory) increases in SKF 82958; in contrast, the D2 antagonist raclopride (25–400 µg/kg, SC) did not significantly increase SKF 82958 self-administration, although raclopride did increase cocaine self-administration. Compensatory increases in self-administration rates are thought to reflect antagonist-induced reductions in drug reinforcement. Hence, we conclude that SKF 82958 self-administration depends on activation of a D1-regulated reinforcement substrate.This work was supported by U.S.P.H.S. grants DA-05107, DA-05379, and DA-07747. All animal procedures were performed in accordance with the Guide for the Care and Use of Laboratory Animals (NIH pub. no. 86-23, revised 1985). 相似文献
13.
A novel self-stimulation methodology involving a fixed-interval (FI-5 s) schedule of reinforcement, microanalysis and threshold
evaluation was used to investigate the effects of cocaine on rats lever pressing for electrical stimulation of the prefrontal
cortex. Cocaine (15 mg/kg) increased medial prefrontal cortex (MPC) self-stimulation rates under FI-5 by a mean of 269% and
reduced current thresholds for self-stimulation. A similar facilitation was evident with self-stimulation of the sulcal prefrontal
cortex. Microanalysis showed that cocaine decreased inter-response times and post-reinforcement pauses, increased responding
in the second and third quartiles of the inter-reinforcement interval (IRI) and decreased responding in the fourth IRI quartile.
Schedule control of responding was still evident following cocaine despite the profound facilitation of response rates. Increased
response rates were seen up to 48 h following a single dose of cocaine, suggesting sensitization of the PFC reinforcement
substrate. The acute effects of cocaine on MPC self-stimulation were completely reversed by the dopamine (DA) D1 antagonist SCH 23390 0.02 mg/kg) and the D2 antagonist raclopride (0.3 mg/kg) but not by naloxone (0.5 mg/kg). These results are consistent with previous studies demonstrating
the PFC as part of the neural substrate mediating cocaine reward. Further, these results implicate DA receptors in the reinforcing
properties of both cocaine and MPC self-stimulation. 相似文献
14.
Sara S Roscioni Bart GJ Dekkers Alwin G Prins Mark H Menzen Herman Meurs Martina Schmidt Harm Maarsingh 《British journal of pharmacology》2011,162(1):193-209
BACKGROUND AND PURPOSE
Changes in airway smooth muscle (ASM) phenotype may contribute to the pathogenesis of airway disease. Platelet-derived growth factor (PDGF) switches ASM from a contractile to a proliferative, hypo-contractile phenotype, a process requiring activation of extracellular signal-regulated kinase (ERK) and p70S6 Kinase (p70S6K). The effects of cAMP-elevating agents on these processes is unknown. Here, we investigated the effects of cAMP elevation by prostaglandin E2 (PGE2) and the activation of the cAMP effectors, protein kinase A (PKA) and exchange protein activated by cAMP (Epac) on PDGF-induced phenotype switching in bovine tracheal smooth muscle (BTSM).EXPERIMENTAL APPROACH
Effects of long-term treatment with the PGE2 analogue 16,16-dimethyl-PGE2, the selective Epac activator, 8-pCPT-2′-O-Me-cAMP and the selective PKA activator, 6-Bnz-cAMP were assessed on the induction of a hypo-contractile, proliferative BTSM phenotype and on activation of ERK and p70S6K, both induced by PDGF.KEY RESULTS
Treatment with 16,16-dimethyl-PGE2 inhibited PDGF-induced proliferation of BTSM cells and maintained BTSM strip contractility and contractile protein expression in the presence of PDGF. Activation of both Epac and PKA similarly prevented PDGF-induced phenotype switching and PDGF-induced activation of ERK. Interestingly, only PKA activation resulted in inhibition of PDGF-induced phosphorylation of p70S6K.CONCLUSIONS AND IMPLICATIONS
Our data indicate for the first time that both Epac and PKA regulated switching of ASM phenotype via differential inhibition of ERK and p70S6K pathways. These findings suggest that cAMP elevation may be beneficial in the treatment of long-term changes in airway disease. 相似文献15.
Rationale: Previous studies suggest that dopamine antagonists may reduce the reinforcing effects of cocaine. However, the effects of
these antagonists on the demand for smoked cocaine base have not been quantified. Objectives: To evaluate the effects of selective D1 (SCH 23390) and D2 (raclopride) dopamine receptor antagonists on the demand for smoked cocaine base in rhesus monkeys using a behavioral economic
analysis. Methods: Six rhesus monkeys were trained to self-administer smoked cocaine base (1.0 mg/kg/delivery) under chained fixed-ratio (FR)
schedules (FR64, 128, 256, 512, 1024 or 2048 for lever presses and FR5 for inhalations) during daily 4-h sessions. A maximum
of ten smoke deliveries were available. After 5 days of stable behavior at each FR, SCH 23390 (0.01 and 0.056 mg/kg) or raclopride
(0.03 and 0.056 mg/kg) were injected intramuscularly, before each session, for 3 consecutive days. Results: Pretreatment with both antagonists dose-dependently reduced cocaine intake across most FR values tested; however, the decrease
in consumption was greater at the higher unit prices than at the lower unit prices. A statistical estimate of the price (FR)
at which maximum responding occurred (Pmax) was decreased during drug pretreatment, indicating weakened reinforcing effectiveness of cocaine. Conclusions: These data suggest that both antagonists reduce the reinforcing effectiveness of smoked cocaine base, and they have a greater
effect on cocaine consumption at higher FR values.
Received: 19 October 1998 / Final version: 1 March 1999 相似文献
16.
The effects of chronic treatment with dopamine (DA) D1 and D2 receptor antagonists were evaluated in eightcebus apella monkeys with mild oral dyskinesia after previous haloperidol treatment. SCH 23390 (D1 antagonist) was given daily to investigate the direct behavioural effect during long-term treatment and the subsequent supersensitivity to DA agonists. Raclopride (D2 antagonist) was investigated for comparison. All drugs were given subcutaneously. SCH 23390 and raclopride induced dystonic syndromes, catalepsy, sedation and reduced locomotor activity. The monkeys developed marked tolerance to the dystonic effect of SCH 23390, while they showed increased sensibility to the dystonic effect of raclopride. Baseline oral dyskinesia (24 h after injection) remained unchanged during D1 antagonist treatment, while it increased during D2 antagonist treatment. SCH 23390 induced supersensitivity to the oral dyskinesia- and grooming-inducing effects of SKF 81297 (D1 agonist) after 9 weeks, while the subsequent treatment with raclopride induced supersensitivity to the reactivity- and stereotypy-inducing effects of quinpirole (D2 receptor agonist) after 3 weeks. Because of the possibility of a carry-over effect (SKF 81297-induced oral hyperkinesia and grooming), other changes in raclopride-induced behaviours cannot be ruled out. The development of tolerance to the dystonic effect of SCH 23390 and the unchanged baseline oral dyskinesia during SCH 23390 treatment indicate an advantageous profile of side effects of DA D1 receptor blockade. 相似文献
17.
Peter Salmi Kristina Malmgren Torgny H. Svensson Sven Ahlenius 《Naunyn-Schmiedeberg's archives of pharmacology》1998,357(6):593-599
In d-amphetamine-treated (4.0 mg kg–1 s.c.) rats the selective dopamine D1 and D2/3 receptor antagonists SCH-23390 (2.5–20.0 μg kg–1 s.c.) and raclopride (12.5–100.0 μg kg–1 s.c.), respectively, produced a biphasic pattern of effects on forward locomotion, as observed in an open-field arena (≈0.5
m2). Thus, at the low doses of SCH-23390 (2.5–10.0 μg kg–1) or raclopride (12.5–50.0 μg kg–1), there was a statistically significant increase in forward locomotion, followed by suppression of the behavior at the higher
doses. The SCH-23390-induced (5.0 μg kg–1) stimulation of forward locomotion was partially antagonized by concomitant raclopride treatment (12.5–25.0 μg kg–1) and the corresponding raclopride-induced (12.5 μg kg–1) stimulation was fully antagonized by treatment with SCH-23390 (2.5–5.0 μg kg–1). Furthermore, the SCH-23390- or raclopride-induced stimulation of forward locomotion was also antagonized by treatment with
the α1-adrenoceptor antagonist prazosin (1.0 mg kg–1 s.c.). These observations suggest that under conditions of an increased general tone at brain dopamine receptors, there is
a mutual inhibitory synergy between dopamine D1 and D2/3 receptors.
Received: 21 July 1997 / Accepted: 6 March 1998 相似文献
18.
Rationale Dopamine D1-like antagonists block several effects of cocaine, including its locomotor-stimulant and discriminative-stimulus effects.
Because these compounds generally lack selectivity among the dopamine D1 and D5 receptors, the specific roles of the subtypes have not been determined.
Objectives Dopamine D5 receptor knockout (DA D5R KO), heterozygous (HET) and wild-type (WT) mice were used to study the role of D5 dopamine receptors in the effects of cocaine. In addition, effects of the D1-like antagonist, SCH 39166 were also studied to further clarify the roles of D1 and D5 dopamine receptors in the discriminative-stimulus effects of cocaine.
Methods DA D5R KO, HET and WT mice were treated with cocaine (3–30 mg/kg) or vehicle and their horizontal locomotor activity was assessed.
The mice were also trained to discriminate IP injections of saline from cocaine (10 mg/kg) using a two-lever food-reinforcement
(FR10) procedure. Doses of cocaine (1.0–10 mg/kg) were administered 5 min before 15-min test-sessions.
Results Cocaine dose-dependently stimulated activity in each genotype, with the highest level of activity induced in the DA D5R WT mice. Both DA D5R KO and HET mice showed reduced levels of horizontal activity compared to WT mice. All three genotypes acquired the discrimination
of 10 mg/kg cocaine; doses of 1.0–10.0 mg/kg produced dose-related increases in the number of cocaine-appropriate responses.
SCH 39166, at inactive to fully active doses (0.01–0.1 mg/kg) produced predominately saline-appropriate responding. SCH 39166
produced a dose-dependent rightward shift in the cocaine dose-effect curve in all genotypes, with similar apparent affinities.
Conclusions The present data suggest an involvement of DA D5R in the locomotor stimulant effects of cocaine. In addition, the data indicate that there is little involvement of the DA
D5R in the discriminative-stimulus effects of cocaine. In addition, the antagonism data suggest a role of the D1 receptor in the behavioral effects of cocaine. 相似文献
19.
Hwang TL Tang MC Kuo LM Chang WD Chung PJ Chang YW Fang YC 《Toxicology and applied pharmacology》2012,260(2):193-200
Alveolar macrophages play significant roles in the pathogenesis of several inflammatory lung diseases. Increases in exhaled nitric oxide (NO) are well documented to reflect disease severity in the airway. In this study, we investigated the effect of 3-(5′-hydroxymethyl-2′-furyl)-1-benzyl indazole (YC-1), a known activator of soluble guanylyl cyclase, on prostaglandin (PG)E1 (a stable PGE2 analogue) and forskolin (a adenylate cyclase activator) induced NO production and inducible NO synthase (iNOS) expression in rat alveolar macrophages (NR8383). YC-1 did not directly cause NO production or iNOS expression, but drastically potentiated PGE1- or forskolin-induced NO production and iNOS expression in NR8383 alveolar macrophages. Combination treatment with YC-1 and PGE1 significantly increased phosphorylation of the cAMP response element-binding protein (CREB), but not nuclear factor (NF)-κB activation. The combined effect on NO production, iNOS expression, and CREB phosphorylation was reversed by a protein kinase (PK)A inhibitor (H89), suggesting that the potentiating functions were mediated through a cAMP/PKA signaling pathway. Consistent with this, cAMP analogues, but not the cGMP analogue, caused NO release, iNOS expression, and CREB activation. YC-1 treatment induced an increase in PGE1-induced cAMP formation, which occurred through the inhibition of cAMP-specific phosphodiesterase (PDE) activity. Furthermore, the combination of rolipram (an inhibitor of PDE4), but not milronone (an inhibitor of PDE3), and PGE1 also triggered NO production and iNOS expression. In summary, YC-1 potentiates PGE1-induced NO production and iNOS expression in alveolar macrophages through inhibition of cAMP PDE activity and activation of the cAMP/PKA/CREB signaling pathway. 相似文献
20.
H. Kuribara 《Psychopharmacology》1995,119(1):34-38
Methamphetamine (2 mg/kg SC) increased ambulation in mice for about 3 h, with a peak effect at around 40 min after the administration, and its repeated administration induced sensitization. Both SCH 23390 (0.03 mg/kg SC) and haloperidol (0.4 mg/kg SC), dopamine D1 and D2 receptor antagonists, respectively, completely inhibited not only the acute stimulant effect of methamphetamine but also its sensitization when repeated methamphetamine was repeatedly combined with either of these drugs. Moreover, treatment with SCH 23390 2–5 h or haloperidol 1–5 h after each methamphetamine administration significantly antagonized methamphetamine sensitization. The maximal inhibitory effect was observed in the schedules of 3-h post-methamphetamine treatment for both drugs. However, treatments with SCH 23390 or haloperidol at 0.5 h, 6 h and 24 h after methamphetamine had no such inhibitory effect. The mice treated with SCH 23390 or haloperidol after each saline administration (the control administration for methamphetamine) did not show significant change in the sensitivity to methamphetamine. These results suggest that methamphetamine has an effect on both dopamine D1 and D2 receptors for several hours even after cessation of its acute stimulant effect, and that such an effect is involved in the induction of sensitization to the stimulant effect of methamphetamine on ambulation in mice. 相似文献