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1.
Health Promot Pract ; 23(1_suppl): 153S-163S, 2022 11.
Article in English | MEDLINE | ID: mdl-36374604

ABSTRACT

Linking clinical services to community-based resources is a promising strategy for assisting patients with chronic disease prevention and management. However, there remains a gap in understanding how to effectively develop and implement community-clinical linkages (CCLs), especially in communities of color. The Healthy Here initiative used Stage Theory of organizational change to implement a centralized wellness referral system, linking primary care clinics to community organizations in majority Hispanic/Latinx and Native American communities. Data were collected using a standardized referral form. Facilitators and challenges were identified through semi-structured discussions with partner organizations. Between 2016 and 2021, 43 clinics and 497 health care providers made 7,465 referrals, the majority of which were from the focus populations. The average proportion of patients referred by clinic champions decreased significantly over time, reflecting diffusion of the intervention within clinics. Facilitators to system success included building on existing networked partnerships, utilizing a centralized referral center, leveraging funding, sharing data, addressing challenges collectively, incorporating multilevel leadership, and co-developing and testing a standardized referral form and process with a single clinic and provider before scaling up. Challenges included funding restrictions, decreasing referrals within clinics over time, changing availability of resources and programs, and the COVID-19 pandemic. This innovative initiative demonstrates that CCLs can be developed and implemented to successfully reach Hispanic/Latinx and Native American communities and provides strategies for overcoming challenges.


Subject(s)
COVID-19 , Pandemics , Humans , Referral and Consultation , Chronic Disease , Delivery of Health Care
2.
J Neurosci ; 40(32): 6133-6145, 2020 08 05.
Article in English | MEDLINE | ID: mdl-32631938

ABSTRACT

The endocannabinoid system plays important roles in brain development, but mechanistic studies have focused on neuronal differentiation, migration, and synaptogenesis, with less attention to transcellular interactions that coordinate neurodevelopmental processes across developing neural networks. We determined that, in the developing rodent cerebellar cortex (of both sexes), there is a transient window when the dominant brain cannabinoid receptor, CB1R, is expressed on afferent terminals instead of output neuron Purkinje cell synapses that dominate the adult cerebellum. Activation of these afferent CB1Rs suppresses synaptic transmission onto developing granule cells, and consequently also suppresses excitation of downstream neurons in the developing cortical network, including nonsynaptic, migrating neurons. Application of a CB1R antagonist during afferent stimulation trains and depolarizing voltage steps caused a significant, sustained potentiation of synaptic amplitude. Our data demonstrate that transiently expressed afferent CB1Rs regulate afferent synaptic strength during synaptogenesis, which enables coordinated dampening of transcortical developmental signals.SIGNIFICANCE STATEMENT The endogenous cannabinoid system plays diverse roles in brain development, which, combined with the rapidly changing legal and medical status of cannabis-related compounds, makes understanding how exogenous cannabinoids affect brain development an important biomedical objective. The cerebellum is a key brain region in a variety of neurodevelopmental disorders, and the adult cerebellum has one of the highest expression levels of CB1R, but little is known about CB1R in the developing cerebellum. Here we report a developmentally distinct expression and function of CB1R in the cerebellum, in which endogenous or exogenous activation of CB1Rs modifies afferent synaptic strength and coordinated downstream network signaling. These findings have implications for recreational and medical use of exogenous cannabinoids by pregnant and breastfeeding women.


Subject(s)
Excitatory Postsynaptic Potentials , Neurogenesis , Neurons, Afferent/metabolism , Purkinje Cells/metabolism , Receptor, Cannabinoid, CB1/metabolism , Action Potentials , Animals , Cannabinoid Receptor Antagonists/pharmacology , Cell Movement , Female , Male , Mice , Mice, Inbred C57BL , Neurons, Afferent/drug effects , Neurons, Afferent/physiology , Purkinje Cells/drug effects , Purkinje Cells/physiology , Receptor, Cannabinoid, CB1/antagonists & inhibitors , Receptor, Cannabinoid, CB1/genetics , Synapses/metabolism , Synapses/physiology
3.
Appetite ; 105: 8-13, 2016 10 01.
Article in English | MEDLINE | ID: mdl-27179937

ABSTRACT

Conditioned cues can elicit drug- and sucrose-seeking behaviors that have been shown to depend on dopamine (DA) D1 receptors. If DAD1 receptors are also involved in seeking behavior in general, blocking these receptors should reduce seeking behavior for a non-caloric, non-drug of abuse reinforcer such as saccharin. Forty-six male Long-Evans rats lever pressed for 0.3% saccharin solution 1 h/day for 10 days. A lever response also activated a tone plus a white stimulus light. This compound stimulus lasted for 5 s. After 1 day of forced abstinence, rats received systemic (0, 1, or 10 µg/kg IP; n = 15-16 per group) injections of SCH 23390 15 min prior to extinction testing. Systemic SCH 23390 reduced saccharin seeking evidenced by a significant reduction in active lever responding and a significant reduction in the number of active lever-contingent deliveries of the tone + light cue following pretreatment with 10 µg/kg SCH 23390. The slope of responding across the Test session in this group was also significantly steeper, indicating that SCH 23390 may have reduced the persistence of saccharin seeking. The results indicate that DAD1 receptors are involved in saccharin seeking and generalize the previously demonstrated anti-seeking effects of DAD1 antagonism to a non-caloric, non-drug of abuse reinforcer.


Subject(s)
Appetite Depressants/administration & dosage , Benzazepines/administration & dosage , Extinction, Psychological/drug effects , Feeding Behavior/drug effects , Overweight/prevention & control , Receptors, Dopamine D1/antagonists & inhibitors , Animals , Appetite Depressants/therapeutic use , Behavior, Animal/drug effects , Benzazepines/therapeutic use , Conditioning, Operant , Craving/drug effects , Cues , Dose-Response Relationship, Drug , Injections, Intraperitoneal , Male , Non-Nutritive Sweeteners/administration & dosage , Overweight/metabolism , Rats, Long-Evans , Receptors, Dopamine D1/metabolism , Reinforcement, Psychology , Reproducibility of Results , Saccharin/administration & dosage
4.
Behav Pharmacol ; 24(8): 633-9, 2013 Dec.
Article in English | MEDLINE | ID: mdl-24113080

ABSTRACT

Dopamine receptors are implicated in the reinforcing effects of food and drug reinforcement. The purpose of this study was to evaluate whether blocking D2 dopamine receptors during extinction (secondary reinforcement) would affect reacquisition of responding for food pellets (primary reinforcement). Food-restricted rats self-administered (fixed-ratio 1) food pellets in 1-h daily sessions for 7 days. For the next 7 days rats responded in extinction conditions. Before each extinction session rats were injected with saline or the dopamine D2 antagonist eticlopride (0.03 mg/kg, subcutaneously). After the extinction phase, rats were allowed to reacquire food pellet self-administration in seven daily sessions, and received saline or eticlopride before each session. Four treatment groups were represented: saline extinction, saline reacquisition; eticlopride extinction, saline reacquisition; saline extinction, eticlopride reacquisition; and eticlopride extinction, eticlopride reacquisition. Locomotor activity did not differ between eticlopride-treated and saline-treated rats throughout the study. Extinction was accelerated in eticlopride-treated rats. Eticlopride also delayed reacquisition of food self-administration compared with saline-treated rats. Rats administered eticlopride during extinction showed delayed reacquisition and a decreased response rate for food during the reacquisition phase. Indirectly reducing the value of a reinforcer in this way may provide a novel approach for reducing addiction-related food or drug self-administration behaviors.


Subject(s)
Conditioning, Operant/drug effects , Dopamine Antagonists/pharmacology , Extinction, Psychological/drug effects , Feeding Behavior/drug effects , Food , Salicylamides/pharmacology , Animals , Body Weight/drug effects , Male , Motor Activity/drug effects , Rats , Self Administration
5.
bioRxiv ; 2023 Jul 08.
Article in English | MEDLINE | ID: mdl-37461463

ABSTRACT

Background: Jansen de Vries Syndrome (JdVS) is a rare neurodevelopmental disorder (NDD) caused by gain-of-function (GOF) truncating mutations in PPM1D exons 5 or 6. PPM1D is a serine/threonine phosphatase that plays an important role in the DNA damage response (DDR) by negatively regulating TP53 (P53). JdVS-associated mutations lead to the formation of a truncated PPM1D protein that retains catalytic activity and has a GOF effect because of reduced degradation. Somatic PPM1D exons 5 and 6 truncating mutations are well-established factors in a number of cancers, due to excessive dephosphorylation and reduced function of P53 and other substrates involved in DDR. Children with JdVS have a variety of neurodevelopmental, psychiatric, and physical problems. In addition, a small fraction has acute neuropsychiatric decompensation apparently triggered by infection or severe non-infectious environmental stress factors. Methods: To understand the molecular basis of JdVS, we developed an induced pluripotent stem cell (iPSC) model system. iPSCs heterozygous for the truncating variant (PPM1D+/tr), were made from a patient, and control lines engineered using CRISPR-Cas9 gene editing. Proteomics and phosphoprotemics analyses were carried out on iPSC-derived glutamatergic neurons and microglia from three control and three PPM1D+/tr iPSC lines. We also analyzed the effect of the TLR4 agonist, lipopolysaccharide, to understand how activation of the innate immune system in microglia could account for acute behavioral decompensation. Results: One of the major findings was the downregulation of POGZ in unstimulated microglia. Since loss-of-function variants in the POGZ gene are well-known causes of autism spectrum disorder, the decrease in PPM1D+/tr microglia suggests this plays a role in the neurodevelopmental aspects of JdVS. In addition, neurons, baseline, and LPS-stimulated microglia show marked alterations in the expression of several E3 ubiquitin ligases, most notably UBR4, and regulators of innate immunity, chromatin structure, ErbB signaling, and splicing. In addition, pathway analysis points to overlap with neurodegenerative disorders. Limitations: Owing to the cost and labor-intensive nature of iPSC research, the sample size was small. Conclusions: Our findings provide insight into the molecular basis of JdVS and can be extrapolated to understand neuropsychiatric decompensation that occurs in subgroups of patients with ASD and other NDDs.

6.
Addict Biol ; 17(3): 623-33, 2012 May.
Article in English | MEDLINE | ID: mdl-22340200

ABSTRACT

Associations between nicotine in cigarettes and food consumption may alter the incentive value of food such that food cue-reactivity is exaggerated during abstinence from smoking. This effect may contribute to the weight gain associated with cessation of smoking. We examined the effects of nicotine (0.4 mg/kg base subcutaneous) paired (NPD) or unpaired (NUP) with 10% sucrose self-administration (SA; 0.2 ml/delivery, 1 h/day for 10 days) on SA response rate and intake as well as sucrose cue-reactivity following either 1 or 30 days of forced abstinence. Rats were administered the training dose of nicotine prior to a second, consecutive cue-reactivity session. NPD rats responded at over three times the rate for sucrose and earned nearly twice the number of sucrose deliveries as NUP rats or saline controls. Sucrose cue-reactivity was greater after 30 days versus 1 day of forced abstinence for all groups. History of nicotine exposure had no effect on sucrose cue-reactivity. However, the subsequent injection of nicotine increased sucrose cue-reactivity only in the NPD groups. There were no abstinent-dependent effects of nicotine challenge on sucrose cue-reactivity. A study conducted in parallel with water as the reinforcer revealed a less dramatic effect of nicotine on intake. There was no history or abstinence-dependent effects of nicotine on water cue-reactivity. Nicotine increases the reinforcing effects of sucrose and sucrose-paired cues when nicotine is present. An implication of these findings is that relapse to nicotine (cigarettes) could substantially elevate food cue-reactivity.


Subject(s)
Ganglionic Stimulants/pharmacology , Nicotine/pharmacology , Sucrose/administration & dosage , Sweetening Agents/administration & dosage , Analysis of Variance , Animals , Body Weight , Conditioning, Operant/drug effects , Feeding and Eating Disorders , Ganglionic Stimulants/administration & dosage , Male , Nicotine/administration & dosage , Rats , Rats, Long-Evans , Reinforcement, Psychology
7.
J Neurodev Disord ; 12(1): 14, 2020 05 11.
Article in English | MEDLINE | ID: mdl-32393163

ABSTRACT

BACKGROUND: Lowe syndrome (LS) is caused by loss-of-function mutations in the X-linked gene OCRL, which codes for an inositol polyphosphate 5-phosphatase that plays a key role in endosome recycling, clathrin-coated pit formation, and actin polymerization. It is characterized by congenital cataracts, intellectual and developmental disability, and renal proximal tubular dysfunction. Patients are also at high risk for developing glaucoma and seizures. We recently developed induced pluripotent stem cell (iPSC) lines from three patients with LS who have hypomorphic variants affecting the 3' end of the gene, and their neurotypical brothers to serve as controls. METHODS: In this study, we used RNA sequencing (RNA-seq) to obtain transcriptome profiles in LS and control neural progenitor cells (NPCs). RESULTS: In a comparison of the patient and control NPCs (n = 3), we found 16 differentially expressed genes (DEGs) at the multiple test adjusted p value (padj) < 0.1, with nine at padj < 0.05. Using nominal p value < 0.05, 319 DEGs were detected. The relatively small number of DEGs could be due to the fact that OCRL is not a transcription factor per se, although it could have secondary effects on gene expression through several different mechanisms. Although the number of DEGs passing multiple test correction was small, those that were found are quite consistent with some of the known molecular effects of OCRL protein, and the clinical manifestations of LS. Furthermore, using gene set enrichment analysis (GSEA), we found that genes increased expression in the patient NPCs showed enrichments of several gene ontology (GO) terms (false discovery rate < 0.25): telencephalon development, pallium development, NPC proliferation, and cortex development, which are consistent with a condition characterized by intellectual disabilities and psychiatric manifestations. In addition, a significant enrichment among the nominal DEGs for genes implicated in autism spectrum disorder (ASD) was found (e.g., AFF2, DNER, DPP6, DPP10, RELN, CACNA1C), as well as several that are strong candidate genes for the development of eye problems found in LS, including glaucoma. The most notable example is EFEMP1, a well-known candidate gene for glaucoma and other eye pathologies. CONCLUSION: Overall, the RNA-seq findings present several candidate genes that could help explain the underlying basis for the neurodevelopmental and eye problems seen in boys with LS.


Subject(s)
Eye Diseases/genetics , Gene Expression Profiling , Induced Pluripotent Stem Cells/metabolism , Neural Stem Cells/metabolism , Oculocerebrorenal Syndrome/genetics , Adolescent , Adult , Cataract/genetics , Cells, Cultured , Child , Endosomes/metabolism , Extracellular Matrix Proteins/genetics , Glaucoma/genetics , Humans , Male , Mutation , Oculocerebrorenal Syndrome/metabolism , Oculocerebrorenal Syndrome/physiopathology , Phosphoric Monoester Hydrolases/genetics , Phosphoric Monoester Hydrolases/metabolism , Reelin Protein , Sequence Analysis, RNA , Young Adult
8.
Mol Autism ; 9: 44, 2018.
Article in English | MEDLINE | ID: mdl-30147856

ABSTRACT

Background: Lowe syndrome (LS) is a rare genetic disorder caused by loss of function mutations in the X-linked gene, OCRL, which codes for inositol polyphosphate 5-phosphatase. LS is characterized by the triad of congenital cataracts, neurodevelopmental impairment (primarily intellectual and developmental disabilities [IDD]), and renal proximal tubular dysfunction. Studies carried out over the years have shown that hypomorphic mutations in OCRL adversely affect endosome recycling and actin polymerization in kidney cells and patient-derived fibroblasts. The renal problem has been traced to an impaired recycling of megalin, a multi-ligand receptor that plays a key role in the reuptake of lipoproteins, amino acids, vitamin-binding proteins, and hormones. However, the neurodevelopmental aspects of the disorder have been difficult to study because the mouse knockout (KO) model does not display LS-related phenotypes. Fortunately, the discovery of induced pluripotent stem (iPS) cells has provided an opportunity to grow patient-specific neurons, which can be used to model neurodevelopmental disorders in vitro, as demonstrated in the many studies that have been published in the past few years in autism spectrum disorders (ASD), schizophrenia (SZ), bipolar disorder (BD), and IDD. Methods: We now report the first findings in neurons and neural progenitor cells (NPCs) generated from iPS cells derived from patients with LS and their typically developing male siblings, as well as an isogenic line in which the OCRL gene has been incapacitated by a null mutation generated using CRISPR-Cas9 gene editing. Results: We show that neuronal cells derived from patient-specific iPS cells containing hypomorphic variants are deficient in their capacity to produce F-filamentous actin (F-actin) fibers. Abnormalities were also found in the expression of WAVE-1, a component of the WAVE regulatory complex (WRC) that regulates actin polymerization. Curiously, neuronal cells carrying the engineered OCRL null mutation, in which OCRL protein is not expressed, did not show similar defects in F-actin and WAVE-1 expression. This is similar to the apparent lack of a phenotype in the mouse Ocrl KO model, and suggests that in the complete absence of OCRL protein, as opposed to producing a dysfunctional protein, as seen with the hypomorphic variants, there is partial compensation for the F-actin/WAVE-1 regulating function of OCRL. Conclusions: Alterations in F-actin polymerization and WRC have been found in a number of genetic subgroups of IDD and ASD. Thus, LS, a very rare genetic condition, is linked to a more expansive family of genes responsible for neurodevelopmental disorders that have shared pathogenic features.


Subject(s)
Actins/metabolism , Induced Pluripotent Stem Cells/cytology , Models, Biological , Neurons/metabolism , Oculocerebrorenal Syndrome/metabolism , Wiskott-Aldrich Syndrome Protein Family/metabolism , Adolescent , Adult , Cells, Cultured , Humans , Male , Polymerization , Young Adult
9.
PLoS One ; 11(12): e0168256, 2016.
Article in English | MEDLINE | ID: mdl-27977779

ABSTRACT

Perineuronal nets (PNNs) are aggregates of extracellular matrix that form structures surrounding a subset of GABAergic interneurons. The staining intensity of PNNs appears to be related to plasticity. Environmental enrichment (EE) influences plasticity during adulthood: EE decreases the rewarding effects of drugs of abuse and diminishes both drug- and sucrose-seeking behavior. We determined the impact of EE on PNN intensity in the medial prefrontal cortex (mPFC) in rats trained to self-administer sucrose. We examined the number and intensity of PNNs within the prelimbic (PL), infralimbic (IL), and orbitofrontal (OF) regions of the mPFC of adult Long-Evans rats that were trained for sucrose self-administration followed by acute or chronic EE during abstinence and a cue-induced reinstatement test. Rats exposed to EE prior to a cue-induced reinstatement of sucrose seeking had an increase in PNN staining compared with rats in standard housing. Conversely, naïve rats given 1 day of EE had a decrease in PNN intensity in the PL, no change in the IL, and an increase in the OF. Our findings demonstrate that EE increases PNN intensity in the mPFC after sucrose training, suggesting that training enhances the ability of EE to increase PNN intensity. We further demonstrate an interaction between time of abstinence, duration of EE exposure, and cue-induced reinstatement. Our results suggest that increased PNN intensity after EE may alter the excitatory/inhibitory balance of mPFC neurons such that rats are less responsive to a sucrose cue.


Subject(s)
Environment , Extinction, Psychological/physiology , Nerve Net/physiology , Neuronal Plasticity/physiology , Prefrontal Cortex/physiology , Sucrose/administration & dosage , Animal Husbandry , Animals , Conditioning, Operant , Cues , Nerve Net/cytology , Nerve Net/drug effects , Prefrontal Cortex/cytology , Prefrontal Cortex/drug effects , Rats , Rats, Long-Evans , Reward , Satellite Cells, Perineuronal/cytology , Self Administration
10.
Brain Struct Funct ; 221(5): 2817-30, 2016 06.
Article in English | MEDLINE | ID: mdl-26068175

ABSTRACT

Exposure to environmental enrichment (EE) reduces sucrose seeking by rats with a history of sucrose self-administration. The present experiment examined whether acute or chronic EE also reduces brain Fos levels, a protein marker indicative of neuronal activation. Fos levels were also examined after either 1 or 30 days of forced abstinence to examine whether Fos levels vary with the incubation of sucrose craving. Fos expression was examined in 18 regions and was identified in brain slices using immunohistochemistry. Fos levels were higher in most regions after 30 days of forced abstinence and were decreased in most regions by either acute or chronic EE. Eleven regions had some statistically significant effect and/or interaction of EE or incubation on Fos; the most salient of these are listed here. In the prelimbic cortex, there was an incubation of Fos and EE reduced Fos at both forced abstinence time points. In contrast, in the orbitofrontal cortex, there was no Fos incubation but EE reduced Fos at both forced abstinence time points. An interaction of EE and incubation was observed in the anterior cingulate cortex and nucleus accumbens core and shell where Fos incubated but EE only decreased Fos at the day 30 forced abstinence time point. In contrast, in the dorsolateral striatum Fos incubated, but EE robustly decreased Fos expression at both forced abstinence time points. These differential expression patterns provide rationale for more detailed, site-specific molecular functional studies in how they relate to the ability of EE to reduce sucrose seeking.


Subject(s)
Brain/physiology , Craving/physiology , Cues , Environment , Sucrose/administration & dosage , Animals , Brain/metabolism , Conditioning, Operant , Male , Proto-Oncogene Proteins c-fos/metabolism , Rats , Rats, Long-Evans
11.
Protein Sci ; 14(9): 2246-57, 2005 Sep.
Article in English | MEDLINE | ID: mdl-16131655

ABSTRACT

Aggregation of partially folded intermediates populated during protein folding processes has been described for many proteins. Likewise, partially unfolded chains, generated by perturbation of numerous proteins by heat or chemical denaturants, have also been shown to aggregate readily. However, the process of protein aggregation from native-state conditions is less well understood. Granulocyte-colony stimulating factor (G-CSF), a member of the four-helix bundle class of cytokines, is a therapeutically relevant protein involved in stimulating the growth and maturation of phagocytotic white blood cells. Under native-like conditions (37 degrees C [pH 7.0]), G-CSF shows a significant propensity to aggregate. Our data suggest that under these conditions, native G-CSF exists in equilibrium with an altered conformation, which is highly aggregation prone. This species is enriched in 1-2 M GdmCl, as determined by tryptophan fluorescence and increased aggregation kinetics. In particular, specific changes in Trp58 fluorescence report a local rearrangement in the large loop region between helices A and B. However, circular dichroism, reactivity toward cyanylation, and ANS binding demonstrate that this conformational change is subtle, having no substantial disruption of secondary and tertiary structure, reactivity of the free sulfhydryl at Cys17 or exposure of buried hydrophobic regions. There is no indication that this altered conformation is important to biological activity, making it an attractive target for rational protein stabilization.


Subject(s)
Granulocyte Colony-Stimulating Factor/chemistry , Biophysical Phenomena , Biophysics , Circular Dichroism , Cysteine/chemistry , Fluorescence , Guanidine/chemistry , Humans , Hydrogen-Ion Concentration , Models, Molecular , Protein Conformation , Protein Denaturation , Recombinant Proteins , Tryptophan/chemistry
12.
PLoS One ; 8(1): e54164, 2013.
Article in English | MEDLINE | ID: mdl-23342096

ABSTRACT

Environmental enrichment (EE) reduces drug and sucrose cue-reactivity in rats. In a previous study we reported that 1 month of EE (large cage, toys, and social cohorts) significantly reduced sucrose cue-reactivity. In the present study, we examined whether overnight (22 h) EE would be as effective. We also examined whether social enrichment (SE), enrichment alone (SoloEE), or exposure to an alternative environment (AEnv) might account for the EE effect. Rats self-administered 10% sucrose (.2 mL/delivery) in 10 daily 2-h sessions. Sucrose delivery was accompanied by a tone+light cue. Rats were then exposed to enrichment or alternative environment conditions overnight (acute) or for 29 days (chronic). Sucrose cue-reactivity was measured after this period of forced abstinence in a session identical to training, but no sucrose was delivered with the cue. All acute conditions markedly reduced sucrose cue-reactivity after 1 day of forced abstinence compared to single-housed rats in standard vivarium housing (CON). Sucrose consumption was also significantly reduced in all groups but SoloEE in a next-day test. All acute conditions but SE significantly reduced sucrose cue-reactivity when administered just prior to Day 30 of forced abstinence; all reduced sucrose consumption in a next-day test. All chronic conditions except for SE and AEnv significantly reduced sucrose cue-reactivity on the Day 30 test and sucrose consumption in a next day test. For both acute and chronic comparisons, EE manipulations were the most effective at reducing sucrose cue-reactivity and consumption. SoloEE and EE were equally effective at reducing sucrose cue-reactivity and similarly effective at reducing sucrose consumption. This indicates that social interaction is not a necessary condition for reducing sucrose-motivated behaviors. These results may be useful in the development of anti-relapse strategies for drug and food addictions.


Subject(s)
Conditioning, Psychological/physiology , Environment , Sucrose/pharmacology , Animals , Behavior, Animal/drug effects , Behavior, Animal/physiology , Drug-Seeking Behavior/drug effects , Drug-Seeking Behavior/physiology , Male , Rats , Rats, Long-Evans , Self Administration , Sucrose/administration & dosage
13.
J Vis Exp ; (57): e3335, 2011 Nov 04.
Article in English | MEDLINE | ID: mdl-22083029

ABSTRACT

For someone on a food-restricted diet, food craving in response to food-paired cues may serve as a key behavioral transition point between abstinence and relapse to food taking. Food craving conceptualized in this way is akin to drug craving in response to drug-paired cues. A rich literature has been developed around understanding the behavioral and neurobiological determinants of drug craving; we and others have been focusing recently on translating techniques from basic addiction research to better understand addiction-like behaviors related to food. As done in previous studies of drug craving, we examine sucrose craving behavior by utilizing a rat model of relapse. In this model, rats self-administer either drug or food in sessions over several days. In a session, lever responding delivers the reward along with a tone+light stimulus. Craving behavior is then operationally defined as responding in a subsequent session where the reward is not available. Rats will reliably respond for the tone+light stimulus, likely due to its acquired conditioned reinforcing properties. This behavior is sometimes referred to as sucrose seeking or cue reactivity. In the present discussion we will use the term "sucrose craving" to subsume both of these constructs. In the past decade, we have focused on how the length of time following reward self-administration influences reward craving. Interestingly, rats increase responding for the reward-paired cue over the course of several weeks of a period of forced-abstinence. This "incubation of craving" is observed in rats that have self-administered either food or drugs of abuse. This time-dependent increase in craving we have identified in the animal model may have great potential relevance to human drug and food addiction behaviors. Here we present a protocol for assessing incubation of sucrose craving in rats. Variants of the procedure will be indicated where craving is assessed as responding for a discrete sucrose-paired cue following extinction of lever pressing within the sucrose self-administration context (Extinction without cues) or as responding for sucrose-paired cues in a general extinction context (Extinction with cues).


Subject(s)
Association Learning , Behavior, Addictive , Behavior, Animal , Feeding Behavior , Food Preferences , Sucrose/administration & dosage , Animals , Conditioning, Classical , Male , Models, Animal , Rats , Rats, Long-Evans
14.
Psychopharmacology (Berl) ; 216(2): 219-33, 2011 Jul.
Article in English | MEDLINE | ID: mdl-21318562

ABSTRACT

RATIONALE: Conditioned cues can elicit relapse to drug- and food-seeking behavior over prolonged periods of abstinence. If seeking behavior depends on mesolimbic dopamine D1 receptors, blocking these receptors should reduce seeking behavior. OBJECTIVES: We examined the effects of either systemic or intra-nucleus accumbens administration of the D1 antagonist SCH 23390 on extinction responding (sucrose seeking) by rats either 1 or 30 days into forced abstinence. MATERIALS AND METHODS: Rats self-administered 10% sucrose paired with a tone + light cue for 10 days. After either 1 or 30 days of forced abstinence, rats received systemic (0, 1, 5, or 25 µg/kg IP) or bilateral nucleus accumbens core or shell (0.3 or 0.6 µg/site) injections of SCH 23390 prior to extinction testing. RESULTS: Saline-treated rats responded more during extinction following 30 vs. 1 day of forced abstinence ("incubation of craving"). Systemic SCH 23390 reduced sucrose seeking after 1 day of forced abstinence, significantly reducing responding following pretreatment with 1, 5, and 25 µg/kg SCH 23390, but only 25 µg/kg significantly reduced sucrose seeking after 30 days of forced abstinence. SCH 23390 (0.3 or 0.6 µg/site) in the core or shell of the nucleus accumbens reduced sucrose seeking in all groups. CONCLUSION: Nucleus accumbens D1 receptors are involved in sucrose seeking, but it is not clear if they are involved in the incubation of craving. The fact that D1 antagonism reduced sucrose seeking across an extended period of abstinence may be of use for development of treatment strategies for relapse.


Subject(s)
Benzazepines/pharmacology , Dopamine Antagonists/pharmacology , Nucleus Accumbens/drug effects , Receptors, Dopamine D1/antagonists & inhibitors , Animals , Behavior, Addictive/prevention & control , Behavior, Animal/drug effects , Benzazepines/administration & dosage , Conditioning, Operant/drug effects , Conditioning, Psychological/drug effects , Cues , Dopamine Antagonists/administration & dosage , Dose-Response Relationship, Drug , Drug-Seeking Behavior/drug effects , Extinction, Psychological/drug effects , Male , Nucleus Accumbens/metabolism , Rats , Rats, Long-Evans , Self Administration , Sucrose/administration & dosage , Time Factors
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