Dopamine agonist

Dopamine agonists are the first line of treatment for patients with symptomatic hyperprolactinemia due to prolactinomas and in those with idiopathic hyperprolactinemia. Treatment with these agents is effective in 80%-90% of the cases. Infertility treatment of patients with hyperprolactinemia is also carried out with dopamine agonists, aiming for the normalization of prolactin levels. The risk of symptomatic growth of prolactinomas during pregnancy is dependent on the tumor's size, duration of previous treatments, and prolactin levels...

The nucleus accumbens (NAc) is a central component of the brain circuitry that mediates motivated behavior, including reward processing. Since the rewarding properties of social stimuli have a vital role in guiding behavior (both in humans and nonhuman animals), the nucleus accumbens is likely to contribute to the brain circuitry controlling social behavior. In rodents, prior studies have found that focal pharmacological inhibition of NAc and/or elevation of dopamine in NAc increases social interactions. However, the role of the NAc in social behavior in nonhuman primates remains unknown...

Prepulse inhibition (PPI) is a crucial indicator of sensorimotor gating that is often impaired in neuropsychiatric diseases. Although dopamine D1 receptor agonists have been found to disrupt PPI in mice, the underlying mechanisms are not fully understood. In this study, we aimed to identify the brain regions responsible for the PPI-disruptive effect of the D1 agonist in mice. Results demonstrated that intraperitoneal administration of the selective dopamine D1 receptor agonist SKF82958 dramatically inhibited PPI, while the dopamine D1 receptor antagonist SCH23390 enhanced PPI...

BACKGROUND: Desensitization of G protein-coupled receptors (GPCRs) refers to the attenuation of receptor responsiveness by prolonged or intermittent exposure to agonists. The binding of β-arrestin to the cytoplasmic cavity of the phosphorylated receptor, which competes with the G protein, has been widely accepted as an extensive model for explaining GPCRs desensitization. However, studies on various GPCRs, including dopamine D2 -like receptors (D2 R, D3 R, D4 R), have suggested the existence of other desensitization mechanisms...

Epidemiological studies report an elevated risk of Parkinson's disease (PD) in patients with type 2 diabetes mellitus (T2DM) that is mitigated in those prescribed dipeptidyl peptidase 4 (DPP-4) inhibitors. With an objective to characterize clinically translatable doses of DPP-4 inhibitors (gliptins) in a well-characterized PD rodent model, sitagliptin, PF-00734,200 or vehicle were orally administered to rats initiated either 7-days before or 7-days after unilateral medial forebrain bundle 6-hydroxydopamine (6-OHDA) lesioning...

LY-404,039 is an orthosteric agonist at metabotropic glutamate 2 and 3 (mGlu2/3) receptors, with a possible additional agonist effect at dopamine D2 receptors. LY-404,039 and its pro-drug, LY-2140023, have previously been tested in clinical trials for psychiatric indications and could therefore be repurposed if they were shown to be efficacious in other conditions. We have recently demonstrated that the mGlu2/3 orthosteric agonist LY-354,740 alleviated L-3,4-dihydroxyphenylalanine (L-DOPA)-induced abnormal involuntary movements (AIMs) in the 6-hydroxydopamine (6-OHDA)-lesioned rat without hampering the anti-parkinsonian action of L-DOPA...

INTRODUCTION: Prolactinomas are the most common type of pituitary gland tumors that secrete overly prolactin. They account for approximately 60% of all hormone-secreting hypophysis tumors. AIM: This study aims to analyze gender differences in patients with prolactinomas who were operated on transsphenoidal surgery and conduct a single-center retrospective analysis of patient data. MATERIAL AND METHODS: This study evaluated the medical records of 109 patients (61 females and 48 males) from 2009 to 2019 at Feofaniya Clinical Hospital of the State Administration of Affairs in Kyiv, Ukraine...

The substantia nigra pars reticulata (SNr), a crucial basal ganglia output nucleus, contains a dense expression of dopamine D1 receptors (D1Rs), along with dendrites belonging to dopaminergic neurons of substantia nigra pars compacta. These D1Rs are primarily located on the terminals of striatonigral medium spiny neurons, suggesting their involvement in the regulation of neurotransmitter release from the direct pathway in response to somatodendritic dopamine release. To explore the hypothesis that D1Rs modulate GABA release from striatonigral synapses, we conducted optical recordings of striatonigral activity and postsynaptic patch-clamp recordings from SNr neurons in the presence of dopamine and D1R agonists...

INTRODUCTION: Bromocriptine is a dopamine receptor agonist used for central hyperthermia with limited data. We describe our single-center experience utilizing bromocriptine for central hyperthermia, including the population treated, most common dosing regimens, adverse events, and discontinuation reasons. METHODS: A retrospective study was conducted screening patients who were admitted to intensive care units for acute neurological insults and administered bromocriptine for central hyperthermia between April 2016 and September 2022...

Uncontrollable stress exposure impairs working memory and reduces the firing of dorsolateral prefrontal cortex (dlPFC) "Delay cells", involving high levels of norepinephrine and dopamine release. Previous work has focused on catecholamine actions on dlPFC pyramidal cells, but inhibitory interneurons may contribute as well. The current study combined immunohistochemistry and multi-scale microscopy with iontophoretic physiology and behavioral analyses to examine the effects of beta1-noradrenergic receptors (β1-ARs) on inhibitory neurons in layer III dlPFC...

Synthetic exendin-4 (EX4, exenatide), is a GLP-1 receptor agonist used clinically to treat glycemia in Type-2 diabetes mellitus. EX4 also promotes weight loss and alters food reward-seeking behaviors in part due to activation of GLP-1 receptors in the mesolimbic dopamine system. Evidence suggests that GLP-1 receptor activity can directly attenuate cue-induced reward seeking. Here, we tested the effects of EX4 (0.6, 1.2, and 2.4 μg/kg, i.p.) on incentive cue (IC) responding, using a task where rats emit a nosepoke response during an intermittent reward-predictive IC to obtain a sucrose reward...

BACKGROUND: Pituitary lactotrophs are under tonic dopaminergic inhibitory control and bromocriptine treatment blocks prolactin secretion. METHODS: Sleep and local field potential were addressed for 72 h after bromocriptine treatments applied during the different stages of the estrus cycle and for 24 h in the early- and middle postpartum period characterized by spontaneously different dynamics of prolactin release in female rats. RESULTS: Sleep changes showed strong dependency on the estrus cycle phase of the drug application...

Achieving optimal treatment outcomes for individuals living with schizophrenia remains challenging, despite 70 years of drug development efforts. Many chemically distinct antipsychotics have been developed over the past seven decades with improved safety and tolerability but with only slight variation in efficacy. All currently prescribed antipsychotics act as antagonists or partial agonists at the dopamine D2 receptor. With only a few possible exceptions, antipsychotic drugs have similar and modest efficacy for treating positive symptoms and are relatively ineffective in addressing the negative and cognitive symptoms of the disease...

Dopamine (DA) D 2 -like receptors in both the central nervous system (CNS) and the periphery are key modulators of metabolism. Moreover, disruption of D 2 -like receptor signaling is implicated in dysglycemia. Yet, the respective metabolic contributions of CNS versus peripheral D 2 -like receptors including D 2 (D2R) and D 3 (D3R) receptors remain poorly understood. To address this, we developed new pharmacological tools, D 2 -like receptor agonists with diminished and delayed blood-brain barrier capability, to selectively manipulate D2R/D3R signaling in the periphery...

Schizophrenia is a disease with a complex pathological mechanism that is influenced by multiple genes. The study of its pathogenesis is dominated by the dopamine hypothesis, as well as other hypotheses such as the 5-hydroxytryptamine hypothesis, glutamate hypothesis, immune-inflammatory hypothesis, gene expression abnormality hypothesis, and neurodevelopmental abnormality hypothesis. The first generation of antipsychotics was developed based on dopaminergic receptor antagonism, which blocks dopamine D2 receptors in the brain to exert antipsychotic effects...

RATIONALE: Antipsychotic medications that are used to treat psychosis are often limited in their efficacy by high rates of severe side effects. Treatment success in schizophrenia is further complicated by high rates of comorbid nicotine use. Dopamine D2 heteroreceptor complexes have recently emerged as targets for the development of more efficacious pharmaceutical treatments for schizophrenia. OBJECTIVE: The current study sought to explore the use of the positive allosteric modulator of the mGlu5 receptor 3-Cyano-N-(1,3-diphenyl-1H-pyrazol-5-yl)benzamide (CDPPB) as a treatment to reduce symptoms related to psychosis and comorbid nicotine use...

INTRODUCTION: Cariprazine is an orally active dopamine D3-preferring D3/D2 receptor and serotonin 5-HT1A receptor partial agonist, being considered as a treatment for refractory MDD. Therefore, we aim to perform the first meta-analysis of current literature, to collate changes in depression from baseline and assess tolerability of adjunctive cariprazine in MDD populace. METHODS: PubMed, Embase, Google Scholar, ClinicalTrials.Gov, and Cochrane Library were searched from inception till 1st September 2023...

INTRODUCTION: Dopaminergic agonists are accepted as the most effective treatment for pituitary pars intermedia dysfunction. However, some horses are refractory to daily oral pergolide, the recommended registered treatment. Extended-release cabergoline (ERC) injection may offer an alternative. The objective of this retrospective case series was to describe clinical and endocrinological responses to ERC. METHODS: Medical records of horses treated with weekly intramuscular injections of ERC (5 mg/mL, BOVA Aus) at either 0...

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BACKGROUND: Hyperprolactinemia is a common antipsychotic-induced adverse event in psychiatric patients, and the quality of clinical studies investigating the best treatments has varied. Thus, to better summarize the clinical evidence, we performed an umbrella review of overlapping systematic reviews and meta-analyses for the treatment of antipsychotic-induced hyperprolactinemia. METHODS: The PubMed, Cochrane Library, PsycINFO, Scopus and EMBASE were searched, and reviews and meta-analyses meeting our inclusion criteria were selected...