| Summary: | 碩士 === 國防醫學院 === 生物及解剖學研究所 === 101 === Attention-deficit/hyperactivity disorder (ADHD), or Attention-deficit disorder (ADD), is a kind of psychiatric disorder. Patients’ symptoms include difficulty in sustaining attention, impulsivity and hyperactivity. ADHD may effect on children and the symptoms can be continually into adulthood. Even though ADHD is yet to be completely established based on pathophysiology; in addition, the previous studies showed that the mainly affected systems seem to be affected the dopamine and serotonin systems. In this study, we will use two radiopharmaceuticals, [123I]ADAM (targeting to serotonin transporters) and [99mTc]-TRODAT-1 (targeting to dopamine transporters) coupled with single photon emission computed tomography (SPECT). Furthermore, another radiopharmaceuticals 4-[18F]-ADAM (targeting to serotonin transporters) coupled with positron emission topography (PET) was imaging the ADHD rat models to address the possible mechanism of the pathophysiology and validity of these imaging techniques. The results showed that the two ADHD rat models have displayed hyperactivity compared to normal rats. In SHR rat (spontaneous ADHD model), it shows higher [123I]ADAM uptakes in various brain regions than those of WKY rat (control group). In contrast, the [123I]ADAM uptakes in brain regions of neonatal 6-OHDA lesion SD rat were less than those of normal SD rat. And the [99mTc]-TRODAT-1 uptakes showed SHR rats had higher uptake in the striatum of than that of WKY rat (control group). Moreover, the immunohistochemical staining results of serotonin transporter and dopamine transporter and the results of SPECT and PET are consistent. Compare with [123I]ADAM /SPECT and 4-[18F]-ADAM /PET, 4-[18F]-ADAM /PET has higher resolution and precision of choosing the volume of interest in various brain regions than [123I]ADAM /SPECT. So 4-[18F]-ADAM /PET can more accurately quantify the various brain regions for analysis. With this study, the roles of monoaminergic system in ADHD may be well understood. Hence, provide useful information in developing the new drugs, and develop better methods to monitor their therapeutic responses.
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