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Degenerative Diseases of the Nervous System
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
James A. Mastrianni, Elizabeth A. Harris
Parkinsonism: Dopaminergic drugs: In order of effectiveness and lower risk–benefit ratio: levodopa, dopamine agonists (bromocriptine > pergolide > lisuride in older literature) may reduce the symptoms in some cases but a sustained response is rare.Amantadine may cause temporary improvement in a small subset of patients.Higher doses of levodopa may be needed for clinical response (up to 1 g daily).Levodopa-induced dyskinesias are rare, but dystonia may occur (dysarthria, apraxia of eyelid closure).Case reports of improvement in some patients with zolpidem, anticholinergics, idazoxan, tricyclic antidepressants, L-threo-3,4-dihydroxy-phenylserine (L-DOPS), methysergide.
Distribution and Characteristics of Brain Dopamine
Published in Nira Ben-Jonathan, Dopamine, 2020
In addition to regulating important neurological functions such as locomotion, cognition and reward, the brain dopaminergic neurons are a critical component of the neuroendocrine functions of the brain. Three dopaminergic pathways, the IHDA, TIDA, and THDA, originate in the hypothalamus, supply DA to most hypothalamic nuclei and link the nervous system to the endocrine system via the pituitary gland. Within the pituitary gland, only the posterior pituitary (both neural and ILs) is directly connected to the hypothalamus through a nerve tract, whereas the anterior lobe is not innervated but, rather, receives hypothalamic information through the specialized hypophysial portal vasculature.
Psychological determinants of substance misuse by young people
Published in Ilana B. Crome, Richard Williams, Roger Bloor, Xenofon Sgouros, Substance Misuse and Young People, 2019
A second set of broadly psychological issues relates to addiction, which is a combination of an overriding compulsion to use a substance and symptoms of withdrawal when the substance is not available. The biological mechanism involves the subcortical dopaminergic reward centres discussed elsewhere in this book. In effect, addiction transfers control from the cortex to subcortical structures, which may account for the dehumanising effect of what Nora Volkow refers to as a ‘disease … of the striatothalamo-orbitofrontal circuit’ (Volkow and Fowler, 2000). Pronounced physiological withdrawal syndromes are unusual in young people who have not had sufficient time for dependency to emerge. However, compulsive drug-taking without marked withdrawals does seem to occur, particularly with stimulants that include novel psychoactive substances that generate ‘a downward cycle of bingeing and periods of recovery associated with depression’ (Advisory Council on the Misuse of Drugs, 2010).
Developmental exposure to the A6-pesticide causes changes in tyrosine hydroxylase gene expression, neurochemistry, and locomotors behavior in larval zebrafish
Published in Toxicology Mechanisms and Methods, 2022
Ahmed Nasri, Pierre-André Lafon, Amine Mezni, Philippe Clair, Nicolas Cubedo, Ezzeddine Mahmoudi, Hamouda Beyrem, Mireille Rossel, Véronique Perrier
TH has been used as a biomarker for dopaminergic neurons since it is a dopamine synthesis enzyme (Pickel et al. 1975). Dopamine is considered is a neurohormone and neurotransmitter that plays a crucial role in regulating animal life by acting in both the central and peripheral nervous systems (Ugrumov et al. 2012). Dopamine in the peripheral nervous system has been reported in the kidneys, carotid bodies, peripheral arteries, and parts of the gastrointestinal, genitourinary, and endocrine systems (Pivonello et al. 2007). The monoaminergic neurons use dopamine as a transmitter, and it contributes to a variety of functional processes in the vertebrates (Zagrean 2014). The very wide distribution of dopaminergic cells in the central nervous system illustrates its involvement in a varied range of central functions, such as motivation (Schultz 2002), learning and memory (Goldman-Rakic 1997), affective and emotional processes (Diehl and Gershon 1992), control of body temperature (Cox et al. 1978), and locomotion (Mok and Munro 1998).
A potential paradigm shift in opioid crisis management: The role of pharmacogenomics
Published in The World Journal of Biological Psychiatry, 2022
David Eapen-John, Ayeshah G. Mohiuddin, James L. Kennedy
Serotonin released from the median raphe nucleus acts on dopaminergic centres in the limbic system. Serotonin is known to have numerous effects in the brain, but it is hypothesised that serotonin and dopamine serve reciprocal functions, with dopamine inducing appetitive or seeking behaviours, and serotonin countering these effects by inhibiting dopaminergic activity (Esposito et al. 2008). A major point of serotonin regulation is at the serotonin transporter (SERT), encoded by the gene SLC6A4. This transporter protein serves to remove serotonin from the synaptic cleft and recycle it into storage in the presynaptic neuron (Yuferov et al. 2021). Variation in dopamine receptor genes and serotonin transporter genes may alter an individual’s tendency for addictive behaviours, such as opioid abuse and may provide useful information regarding the individualised risk of opioid prescription for pain management.
Is pharmacotherapy useful for treating personality disorders?
Published in Expert Opinion on Pharmacotherapy, 2021
Jutta Stoffers-Winterling, Birgit Völlm, Klaus Lieb
In contrast to paranoid and schizoid PD, schizotypal PD has been subject to some drug treatment research. It is regarded as a schizophrenia spectrum disorder due to an elevated risk of developing schizophrenia and shared phenomenologic, genetic, and neurobiological features. Furthermore, as in schizophrenia, preliminary research suggests a dysregulation of the dopaminergic system and responsiveness to antipsychotic treatment. To date, there are three placebo-controlled RCTs indicating therapeutic effects of the second-generation antipsychotic risperidone on self-monitoring, executive functions, and positive as well as negative schizophrenia symptoms [10]. Additional small, placebo-controlled experimental studies report positive effects on working memory after administration of dopamine receptor agonists (pergolide, dihydrexidine), an α2-agonist (guanfacine) and a cholinesterase inhibitor (physostigmine) [11].