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Radiopharmaceuticals for Diagnostics
Published in Michael Ljungberg, Handbook of Nuclear Medicine and Molecular Imaging for Physicists, 2022
Jim Ballinger, Jacek Koziorowski
The function of the dopamine transporter is reuptake of dopamine released into the synapse into vesicles in the presynaptic nerve terminal. The dopamine transporter can be imaged with an 123I-labelled analogue of cocaine, ioflupane (fluoropropyl carbomethoxy iodophenyl nortropane, FP-CIT, Datscan, Striascan). Ioflupane binds to the transporter to give an indication of the density of presynaptic nerve terminals. SPECT imaging is performed at a fixed time, 3-6 h after injection [16]. In normal individuals there is bilateral homogeneous accumulation of activity in the basal ganglia (striatum; caudate nucleus and putamen). Parkinson’s disease involves degeneration of the nigrostriatal pathway with loss of dopaminergic nerve terminals. Thus, dopamine transporter imaging can be used to diagnose Parkinson’s disease and to differentiate it from other causes of Parkinsonian tremor, such as essential tremor (i.e. non-degenerative) or that caused by certain neuroleptic drugs. In early Parkinson’s disease there tends to be asymmetry, particularly in the putamen, while in advanced disease there is bilateral degeneration. Ioflupane is also useful in diagnosis of Lewy body disease [17].
Sleep–Wake Disorders
Published in Philip B. Gorelick, Fernando D. Testai, Graeme J. Hankey, Joanna M. Wardlaw, Hankey's Clinical Neurology, 2020
Margaret Kay-Stacey, Eunice Torres-Rivera, Phyllis C. Zee
Although the pathophysiology of this disorder remains poorly understood, its association with parkinsonism is possibly related to deficits in dopamine transporter activity in the striatum. Deficits in glutaminergic pathways have also been described.
Biogenic amines
Published in William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop, Atlas of Inherited Metabolic Diseases, 2020
William L. Nyhan, Georg F. Hoffmann, Aida I. Al-Aqeel, Bruce A. Barshop
Definitive diagnosis of the dopamine transporter deficiency syndrome is by demonstrating homozygous/compound heterozygous pathogenic variants of the SLC6A3 gene located at 5p15.33 [43]. Dopamine is synthesized in the pre-synaptic dopaminergic neuron, packaged into synaptic vesicles and transported to the synaptic membrane for release into the synapse and action at dopaminergic receptors at the post-synaptic membrane. The dopamine transporter actively retrieves dopamine from the synaptic cleft and is the principal regulator of dopaminergic neurotransmission.
Driving risks of young drivers with symptoms of attention deficit hyperactivity disorder: association with the dopamine transporter gene VNTR polymorphism
Published in Nordic Journal of Psychiatry, 2022
Tõnis Tokko, Grete Miškinyte, Diva Eensoo, Jaanus Harro
Of the neural substrates of impulsive behaviour, the dopaminergic system has received much attention (e.g. [23]), and dopaminergic dysfunction indeed occurs also in people with attention-deficit/hyperactivity disorder (ADHD) [24,25]. Altered dopamine transporter function is the most consistently observed neurochemical characteristic of ADHD [26]. The dopamine transporter plays a critical role in terminating the effect of synaptically released dopamine by taking it up into neurons [27]. Dopamine transporter is encoded by the DAT1 gene (SLC6A3) that bears a variable number of tandem repeats (VNTR) polymorphism (rs28363170) of a 40-base pair sequence in the 3′-untranslated region of the gene [28]. It has been shown that the DAT1 VNTR 9-repeat (9 R) allele carriers have higher striatal dopamine transporter availability than do the 10-repeat (10 R) allele homozygotes [29,30]. The increased levels of DAT might lead to more efficient clearing of extracellular dopamine, resulting in lower extracellular levels and reduced dopamine signalling [29]. Being a 9 R carrier has been associated with persistent ADHD in adults [31,32]. This genotype can also be associated with traffic risks: We have previously found that male 9 R carriers had more accidents in traffic by their own fault [33] and, in another sample, a higher general traffic risk [34].
Association between dopamine transporter gene (DAT1/SLC6A3) variants and infertility in the Turkish females
Published in Gynecological Endocrinology, 2022
Orcun Avsar, Nesibe Derinoz, Filiz Yilmaz, Musa Yilmaz, Umit Gorkem
Prolactin secretion is regulated by tuberoinfundibular dopaminergic pathway in a negative manner. Disturbances in dopamine neurotransmission may cause abnormal prolactin gene expression and secretion. Dopamine transporter (DAT) reuptakes dopamine from synaptic cleft into presynaptic dopaminergic neuron and terminates neurotransmission. Mutations in SLC6A3 gene that encodes dopamine transporter protein may be related with numerous human diseases. In the literature, no studies that investigated the relationship between tuberoinfundibular dopaminergic pathway or dopamine neurotransmission and female infertility were found. The present study is the first one for investigating the relationship between DAT1/SLC6A3 gene polymorphism and infertility in females. No significant differences were reported between infertile females and corresponding fertile subjects in DAT1/SLC6A3 gene. Our study demonstrated that DAT1/SLC6A3 gene polymorphism is not correlated with female infertility. On the other hand, the present study offers new ideas for further human infertility studies. Further studies in Turkish and other ethnic groups with larger sample size are needed for the evaluation of the effects of DAT1/SLC6A3 gene polymorphisms in female infertility.
Dopaminergic and glutamatergic biomarkers disruption in addiction and regulation by exercise: a mini review
Published in Biomarkers, 2022
Muhammad Abdullah, Li-Chung Huang, Shih-Hsien Lin, Yen Kuang Yang
Dopamine transporters could be one of the important therapeutic targets for the treatment of drug addiction (Desai et al.2005). DAT availability, as discussed in a section above, is enhanced by cocaine while other stimulants and sedative substances cause attenuation. DAT regulation is diverse in terms of the effects of addictive substances. Similarly, exercise exists with diverse findings as an intervention to modulate DAT availability. Like addictive substances, exercise also causes attenuation of DAT, which can lead to an increased basal dopamine level. A Parkinsonian MPTP (1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine) mouse model studied for the effect of chronic exercise on DAT expression showed downregulation of DAT availability which can increase the basal dopamine level (Fisher et al.2004). However, some studies have reported no change after chronic exercise intervention (Robison et al.2018). According to extensive evidence of DAT downregulation by addictive substances (Ashok et al.2017) it is plausible that it could be a compensatory mechanism by which to cope with the decreased basal level of dopamine, and exercise-induced DAT downregulation may be a potential therapeutic mechanism to increase basal dopamine level.