scholarly journals Activation of D1/5 Dopamine Receptors: A Common Mechanism for Enhancing Extinction of Fear and Reward-Seeking Behaviors

2016 ◽  
Vol 41 (8) ◽  
pp. 2072-2081 ◽  
Author(s):  
Antony D Abraham ◽  
Kim A Neve ◽  
K Matthew Lattal
Keyword(s):  
Dopamine Receptors ◽  
Common Mechanism ◽  
Reward Seeking

Commentary on Dinan's Hypothesis

1987 ◽  
Vol 151 (4) ◽  
pp. 459-460 ◽  
Author(s):  
Leslie L. Iversen
Keyword(s):  
Dopamine Receptors ◽  
Drug Action ◽  
Common Mechanism ◽  
Neuroleptic Drug ◽  
Pharmacological Properties ◽  
Neuroleptic Drugs ◽  
Dopamine Hypothesis ◽  
Potent Antagonist ◽  
D2 Antagonists ◽  
Rich Spectrum

Dinan's paper seeks to question the validity of the now widely accepted hypothesis that neuroleptic drugs of various different chemical categories all act by a common mechanism, namely by blockade of dopamine receptors of the D2 type in brain (for review see Creese et al, 1978, 1983; Iversen, 1985). While it is always refreshing to re-examine existing scientific dogma, his criticisms did not appear to me to be very substantial. Having quite fairly reviewed the evidence in favour of the “dopamine hypothesis” for neuroleptic drug action, Dinan summarises his reasons for questioning it. He points out that many neuroleptic drugs have potent actions on a number of other targets, apart from the dopamine receptors in brain. This is indeed so, and the archetypal compound, chlorpromazine, has a particularly rich spectrum of pharmacological activity, being a potent antagonist of serotonin (5-HT2) receptors, ?-adrenoceptors, and histamine (HI) receptors in brain and other tissues. Other neuroleptics also have potent actions on a number of other systems. Indeed, if one were to have studied only chlorpromazine, it is doubtful whether the “dopamine hypothesis” could ever have been developed. The strength of this hypothesis lies in the fact that of all the diverse pharmacological actions which different neuroleptic drugs exhibit, this is the only action that is common to all neuroleptic compounds. Furthermore, in a large group of neuroleptics, which differ widely in potency (doses in man ranging from 1 mg/day to almost 1000 mg/day), the potencies of these drugs as dopamine (D2) antagonists correlate significantly with their clinical potencies. Attempts to make such correlations with any other known pharmacological properties of these drugs fail to show significance (Creese et al, 1978, 1983).

Individual Differences in Nucleus Accumbens Dopamine Receptors Predict Development of Addiction-Like Behavior: A Computational Approach

2010 ◽  
Vol 22 (9) ◽  
pp. 2334-2368 ◽  
Author(s):  
Payam Piray ◽  
Mohammad Mahdi Keramati ◽  
Amir Dezfouli ◽  
Caro Lucas ◽  
Azarakhsh Mokri
Keyword(s):  
Individual Differences ◽  
Nucleus Accumbens ◽  
Dopamine Receptors ◽  
Drug Exposure ◽  
Dorsal Striatum ◽  
Learning Rate ◽  
Common Mechanism ◽  
Drug Reinforcement ◽  
Aversive Stimuli ◽  
Individual Vulnerability

Clinical and experimental observations show individual differences in the development of addiction. Increasing evidence supports the hypothesis that dopamine receptor availability in the nucleus accumbens (NAc) predisposes drug reinforcement. Here, modeling striatal-midbrain dopaminergic circuit, we propose a reinforcement learning model for addiction based on the actor-critic model of striatum. Modeling dopamine receptors in the NAc as modulators of learning rate for appetitive—but not aversive—stimuli in the critic—but not the actor—we define vulnerability to addiction as a relatively lower learning rate for the appetitive stimuli, compared to aversive stimuli, in the critic. We hypothesize that an imbalance in this learning parameter used by appetitive and aversive learning systems can result in addiction. We elucidate that the interaction between the degree of individual vulnerability and the duration of exposure to drug has two progressive consequences: deterioration of the imbalance and establishment of an abnormal habitual response in the actor. Using computational language, the proposed model describes how development of compulsive behavior can be a function of both degree of drug exposure and individual vulnerability. Moreover, the model describes how involvement of the dorsal striatum in addiction can be augmented progressively. The model also interprets other forms of addiction, such as obesity and pathological gambling, in a common mechanism with drug addiction. Finally, the model provides an answer for the question of why behavioral addictions are triggered in Parkinson's disease patients by D2 dopamine agonist treatments.

scholarly journals Antagonism of D1, but not D2, dopamine receptors inhibits cued sucrose seeking by decreasing arousal

2021 ◽  
Author(s):  
Marcin Kaźmierczak ◽  
Saleem M Nicola
Keyword(s):  
Nucleus Accumbens ◽  
Dopamine Receptors ◽  
Behavioral Effects ◽  
Extensive Literature ◽  
D2 Dopamine Receptors ◽  
Reward Seeking ◽  
Novel Synthesis ◽  
D2 Antagonist ◽  
The Relationship

Dopamine facilitates approach to reward via its actions on dopamine receptors in the nucleus accumbens. For example, blocking either D1 or D2 dopamine receptors in the accumbens reduces the proportion of reward-predictive cues to which rats respond with cued approach. Recent evidence indicates that accumbens dopamine also promotes wakefulness and arousal, but the relationship between dopamine's roles in arousal and reward seeking remains unexplored. Here, we show that the ability of systemic or intra-accumbens injections of the D1 antagonist SCH23390 to reduce cued approach to reward depends on the animal's state of arousal. Handling the animal, a manipulation known to increase arousal, was sufficient to reverse the behavioral effects of the antagonist. In addition, SCH23390 reduced spontaneous locomotion and increased time spent in sleep postures, both consistent with reduced arousal, but also increased time spent immobile in postures inconsistent with sleep. In contrast, the ability of the D2 antagonist haloperidol to reduce cued approach was not reversible by handling. Haloperidol reduced spontaneous locomotion but did not increase sleep postures, instead increasing immobility in non-sleep postures. We place these results in the context of the extensive literature on dopamine's contributions to behavior, and propose the arousal-motor hypothesis, a novel synthesis that accounts both for our findings and many previous results that have drawn disparate and conflicting conclusions.

Hope, exploration, and equilibrated action schemes

2019 ◽  
Vol 42 ◽  
Author(s):  
Davood G. Gozli ◽  
Ci Jun Gao
Keyword(s):  
Single Type ◽  
Reward Seeking ◽  
Stable Scheme

AbstractThe concepts want, hope, and exploration cannot be organized in relation to a single type of motive (e.g., motive for food). They require, in addition, the motive for acquiring and maintaining a stable scheme that enables reward-directed activity. Facing unpredictability, the animal has to seek not only reward, but also a new equilibrated state within which reward seeking is possible.

Remission of Recurrent Cochlear Hydrops Associated With Bromocriptine Treatment for Macroprolactinoma

2019 ◽  
Vol 28 (3) ◽  
pp. 548-552
Author(s):  
Andro Košec ◽  
Ivan Kruljac ◽  
Jakov Ajduk
Keyword(s):  
Dopamine Receptors ◽  
Male Patient ◽  
Endolymphatic Hydrops ◽  
Young Male ◽  
Oral Steroid ◽  
Case Description ◽  
Diuretic Treatment ◽  
Potential Therapeutic Role ◽  
Transient Improvement ◽  
Systemic Glucocorticoids

Objective Current recommendations for cochlear hydrops treatment include systemic glucocorticoids and diuretics. Cochlear cells express dopamine receptors, although their role is unknown in the pathophysiology of cochlear hydrops. Case Description We report the case of remission of recurrent right-sided cochlear hydrops in a young male patient treated with bromocriptine due to pituitary macroprolactinoma. Transient improvement was observed after oral steroid and diuretic treatment, but cochlear hydrops recurred until the dose of bromocriptine was increased to 10 mg daily. Conclusion Bromocriptine may stimulate dopamine receptors in cochlear cells with potential therapeutic role in patients with cochlear hydrops. There are no widely accepted and effective treatments for endolymphatic hydrops, and identifying potential new and efficacious therapeutics is of high relevance.

The Diversity of the Dopamine Receptors

1992 ◽  
Author(s):  
Olivier Civelli ◽  
◽  
James R. Bunzow ◽  
Qun-Yong Zhou ◽  
David K. Grandy
Keyword(s):  
Dopamine Receptors

Kindler's Syndrome with Recurrent Neutropenia: Report of Two Cases from Saudi Arabia

2020 ◽  
Author(s):  
Yousef Binamer ◽  
Muzamil A. Chisti
Keyword(s):  
Autosomal Recessive ◽  
Common Mechanism ◽  
Sequencing Analysis ◽  
Loss Of Function ◽  
Skin Atrophy ◽  
Whole Exome ◽  
Infancy And Childhood ◽  
Genetics And Genomics ◽  
New Feature ◽  
Generation Sequencing

AbstractKindler syndrome (KS) is a rare photosensitivity disorder with autosomal recessive mode of inheritance. It is characterized by acral blistering in infancy and childhood, progressive poikiloderma, skin atrophy, abnormal photosensitivity, and gingival fragility. Besides these major features, many minor presentations have also been reported in the literature. We are reporting two cases with atypical features of the syndrome and a new feature of recurrent neutropenia. Whole exome sequencing analysis was done using next-generation sequencing which detected a homozygous loss-of-function (LOF) variant of FERMT1 in both patients. The variant is classified as a pathogenic variant as per the American College of Medical Genetics and Genomics guidelines. Homozygous LOF variants of FERMT1 are a common mechanism of KS and as such confirm the diagnosis of KS in our patients even though the presentation was atypical.

STUDY OF PEDIATRIC INJURIES: PATTERNS AND OUTCOME

2019 ◽  
Vol 3 (8) ◽  
Author(s):  
Yasir. B. Elshambaty
Keyword(s):  
School Level ◽  
Common Mechanism ◽  
Injury Patterns ◽  
Severe Injuries ◽  
Injured Child ◽  
Cross Sectional ◽  
Pediatric Injuries ◽  
Pediatric Injury ◽  
The Common ◽  
Structured Questionnaire

Purpose this study aims to show the patterns and outcome of pediatric injury among those living in Albaha region in Saudi Arabia Methods this is a cross-sectional descriptive household-based study, included children between 0-17 years old both male and female. The data were collected with structured questionnaire between 20 Nov – 20 Dec 2018 and  analyzed with SPSS version 25 Results the total of participants was 257 injured child. 199(77.4%) are male and 58(22.6%) are female. About 44%of them were injured at pre-school level and 56% were traumatized at school age. The least incidence of injury occurred in those less than 2 yrs and higher incidence in those between 3-10 yrs old. The most common mechanism of injury was falling from height. The most affected group age by RTA accidents was 11-17 yrs old. Approximately 83% of the injured children required hospital management. Only one third of the injuries were  associated complications. The most common injured anatomic part was the upper limb and the least affected part was the spine. Only 5% of the injuries were associated with a disability and the common was loss of organ or part of it. Paralysis occurred in less than 1% and head injury resulted in disabilities more than 1%. Conclusion the vast majority of the injuries in our participants are not serious. The severe injuries were associated with RTA-related trauma. Most of injuries due to falling from height are not serious. We recommend not to allow the children to drive cars. Keywords: pediatric injuries; injury patterns; household.

Sign in / Sign up

Export Citation Format

Share Document