No abstract available
Dopamine*

The primary purpose of this review is to present an overview of relationship between human spontaneous eyeblinking and internal cognitive processes. The second purpose is to address the neural substrates of human eyeblinking based on recent studies focusing on the central dopaminergic system and to explore the significance of spontaneous eyeblinks in neuropsychiatric disorders. We reviewed recent and previous studies on eyeblink patterns under various cognitive tasks. We also reviewed neural substrates of eyeblinking, particularly based on the central dopaminergic system. This paper suggests that spontaneous eyeblinks are highly correlated with various cognitive processes and the activity of central dopaminergic system. Various neuropsychiatric disorders are related to the alteration of the occurrence of eyeblinking. Spontaneous eyeblinking is the unique human behavior that occurs regularly without conscious effort. It is known that the rate of eyeblinking is modulated by internal cognitive processes and dopamine-related neuropsychiatric disorders. Further research is required to how the temporal dynamics of spontaneous eyeblinking is correlated with the disease activity and progression.
Dopamine ; Humans

No abstract available.
Dopamine* ; Parkinson Disease* ; Receptors, Dopamine*

OBJECTIVES: We investigated the relationship of personality traits with dopamine D4 receptor(DRD4) exon III polymorphism in a Korean population. METHODS: We analysed DRD4 exon III 48-bp repeats polymorphism in 173 Korean healthy female adolescents(age=13.88+/-0.29 years) who also completed Temperament and Character Inventory(TCI). RESULTS: Novelty seeking score of the TCI was significantly higher in the subjects with DRD4 long alleles(>or=5 repeats) compared with the subjects without these(t=2.11, p=0.037). CONCLUSION: The present study supports the previous reports that long repeats of the DRD4-exon III polymorphism are related with Novelty Seeking personality.
Dopamine* ; Exons ; Female ; Humans ; Receptors, Dopamine* ; Temperament

No abstract available.
Bromocriptine* ; Dopamine Agonists* ; Dopamine* ; Fertility* ; Hyperprolactinemia* ; Lisuride*

No abstract available.
Dopamine ; Parkinson Disease

Desensitization and acute tolerance are terms used to describe the attenuation of receptor responsiveness by prolonged or intermittent exposure to an agonist. Unlike desensitization of G protein-coupled receptors (GPCRs), which is commonly explained by steric hindrance caused by the β-arrestins that are translocated to the activated receptors, molecular mechanisms involved in the acute tolerance of GPCRs remain unclear. Our studies with several GPCRs and related mutants showed that the acute tolerance of GPCRs could occur independently of agonist-induced β-arrestin translocation. A series of co-immunoprecipitation experiments revealed a correlation between receptor tolerance and interactions among receptors, β-arrestin2, and Gβγ. Gβγ displayed a stable interaction with receptors and β-arrestin2 in cells expressing GPCRs that were prone to undergo tolerance compared to the GPCRs that were resistant to acute tolerance. Strengthening the interaction between Gβγ and β-arrestin rendered the GPCRs to acquire the tendency of acute tolerance. Overall, stable interaction between the receptor and Gβγ complex is required for the formation of a complex with β-arrestin, and determines the potential of a particular GPCR to undergo acute tolerance. Rather than turning off the signal, β-arrestins seem to contribute on continuous signaling when they are in the context of complex with receptor and Gβγ.
Immunoprecipitation ; Receptors, Dopamine D3

No abstract available.
Dopamine* ; Injections, Spinal*

No abstract available.
Dopamine* ; Injections, Spinal*

It has recently been reported that both norepinephrine and dopamine elicit antidiuresis when given intracerebroventricularly. But no inference has been made as to their mechanisms. As dopamine is the immediate precursor of norepinephrine in the biosynthesis of catecholamine, it might be possible that dopamine might act indirectly through increased level of norepinephrine in the brain tissue. To certify whether the dopamine-induced antidiuresis is related to norepinephrine, the influence of phentolamine, a specific alpha-adrenergic blocking agent, on the centrally induced antidiuresis of both norepinephrine and dopamine was investigated in this study. Norepinephrine and dopamine given intraventricularly elicited maximal antidiuresis in doses of 10ug and 500ug, respectively. Phentolamine, administered intravenously in dose of 2mg/kg, abolished the renal effect of norepinephrine given intraventricularly, but did not influence the antidiuresis induced by dopamine. It is suggested that both norepinephrine and dopamine produce antidiuresis when given intracerebroventricularly but their actions are mediated by different mechanisms, and that norepinephrine does not participate in the renal action of dopamine.
Brain ; Dopamine* ; Norepinephrine* ; Phentolamine*