Adenosine A_2A receptors are highly enriched in the basal ganglia system, a region that is functionally implicated in schizophrenia. Preclinical evidence suggests a cross-regulation between adenosine A_2A and dopamine D₂ receptors in this region and that it is linked to the sensitization of the dopamine system. However, the relationship between A_2A receptor availability and schizophrenia has not been directly examined in vivo in patients with this disorder. To investigate, using positron emission tomography (PET), the availability of A_2A receptors in patients diagnosed with schizophrenia in comparison to matched healthy controls. A_2A receptor availability was measured using the PET tracer [¹¹C]SCH442416. Twelve male patients with chronic schizophrenia were compared to 13 matched healthy subjects. All patients were medicated with antipsychotics and none presented with any motor or extrapyramidal symptoms. Binding potential (BP_ND), a ratio measure between specific and non-specific tracer uptake, were compared between the groups for the caudate, putamen, accumbens and globus pallidum. There was no differences between A_2A receptor binding potential (BP_ND) of schizophrenia patients in the caudate (p = 0.16), putamen (p = 0.86), accumbens (p = 0.44) and globus pallidum (p = 0.09) to that of matched healthy subjects. There was also no significant correlation between [11C]SCH442416 binding and severity of psychotic symptoms (p = 0.2 to 0.82) or antipsychotic dosage (p = 0.13 to 0.34). By showing that A2A receptor availability in medicated patients with chronic male schizophrenia is not different than in healthy controls, this study does not support the primary role of this receptor in the pathogenesis of schizophrenia.

腺苷 A _2A受体在基底神经节系统中高度富集，该区域在功能上与精神分裂症有关。_{临床前证据表明该区域的腺苷 A 2A}和多巴胺 D ₂受体之间存在交叉调节，并且它与多巴胺系统的致敏作用有关。然而，尚未在患有这种疾病的患者体内直接检查A _2A受体可用性与精神分裂症之间的关系。为使用正电子发射断层扫描 (PET) 调查，与匹配的健康对照相比，诊断为精神分裂症的患者中A _2A受体的可用性。2A _{_}使用 PET 示踪剂 [ ¹¹ C]SCH442416 测量受体可用性。将 12 名患有慢性精神分裂症的男性患者与 13 名匹配的健康受试者进行了比较。所有患者都服用了抗精神病药，没有人出现任何运动或锥体外系症状。结合电位 (BP _ND )，一种特异性和非特异性示踪剂摄取之间的比率测量，在尾状核、壳核、伏隔核和苍白球的组之间进行了比较。尾_状核( p = _0.16  )、壳核 ( p  = 0.86)、伏隔核 ( p  = 0.44) 和苍白球 ( p = 0.09) 到匹配的健康受试者。[11C]SCH442416 结合与精神病症状的严重程度 ( p  = 0.2 至 0.82) 或抗精神病药物剂量 ( p  = 0.13 至 0.34)之间也没有显着相关性。通过显示 A2A 受体在接受药物治疗的慢性男性精神分裂症患者中的可用性与健康对照组没有差异，本研究不支持该受体在精神分裂症发病机制中的主要作用。