Environmental enrichment enhances synaptic plasticity by internalization of striatal dopamine transporters.

Environmental enrichment (EE) with a complex combination of physical, cognitive and social stimulations enhances synaptic plasticity and behavioral function. However, the mechanism remains to be elucidated in detail. We aimed to investigate dopamine-related synaptic plasticity underlying functional improvement after EE.

Dopaminergic neuron destruction reduces hippocampal serotonin 1A receptor uptake of trans-[(18)F]Mefway.

The purpose of the present study is to investigate the relationship between dopaminergic neuron destruction and 5-HT system changes in a hemiparkinsonian rat model. We performed PET imaging studies with trans-[(18)F]Mefway in a hemiparkinsonian model of unilateral 6-hydroxydopamine (6-OHDA) rats. Region-of-interests (ROIs) were drawn in the hippocampus (HP) and cerebellum (CB).

Acute physical stress induces the alteration of the serotonin 1A receptor density in the hippocampus.

Stress affects the serotonergic system, which is associated with depression. Previous research has showed that chronic stress causes the deactivation of the limbic system. However, the influence of the acute physical stress on the serotonergic system in vivo was primarily unclear.

Evaluation of dopamine transporters and D2 receptors in hemiparkinsonian rat brains in vivo using consecutive PET scans of [18F]FPCIT and [18F]fallypride.

The aim of this study was to investigate dopaminergic function in unilaterally lesioned 6-OHDA rats by dual PET radioligands: [(18)F]FPCIT (a dopamine transporter imaging radioligand) and [(18)F]fallypride (a dopamine D2 receptors imaging radioligand). As a result, the brain uptake of [(18)F]FPCIT was significantly reduced and that of [(18)F]fallypride was increased in the ipsilateral striatum (lesion side) of the 6-OHDA rats. These findings implicated that dopamine transporter is down-regulated and dopamine D2 receptor is up-regulated in this hemiparkinsonian rat model.

Effective microPET imaging of brain 5-HT(1A) receptors in rats with [(18) F]MeFWAY by suppression of radioligand defluorination.

Introduction: [(18) F]MeFWAY has been developed for imaging the serotonin 1A receptors in the brain. The purpose of this study were to verify the metabolic stability of [(18) F]MeFWAY, to measure the degree of defluorination of [(18) F]MeFWAY in vivo, to investigate methods of inhibition of defluorination of [(18) F]MeFWAY, and to assess the efficacy of [(18) F]MeFWAY in rat brains in vivo.

Methods: MicroPET experiments in rats were conducted to confirm the distribution of radioactivity in the brain.