The existence of nonadrenergic, noncholinergic nerve components in the autonomic nervous system is now well established. They are strongly represented in the gastrointestinal tract of all vertebrates and have been identified in a variety of other organs, including lung, trachea, bladder, esophagus, eye, seminal vesicles, and possibly parts of the vascular and central nervous systems. Their ultrastructural identification and transmission properties are known and their physiological role is beginning to be understood, at least in the gastrointestinal tract. Evidence that ATP is the transmitter released from nonadrenergic, noncholinergic (purinergic) nerves includes: (a) synthesis and storage of ATP in nerves; (b) release of ATP from the nerves when they are stimulated; (c) exogenously applied ATP mimicking the action of nerve-released transmitter, both producing a specific increase in K+ conductance; (d) the presence of Mg-activated ATPase, 5'nucleotidase, and adenosine deaminase, enzymes, which inactivate ATP; (e) drugs (including 2-substituted imidazolines, 2,2'-pyridylisatogen and dipyridamole), that produce similar blocking or potentiating effects on the response to exogenously applied atp and nerve stimulation.
自主神经系统中存在非肾上腺素能、非胆碱能神经成分，这一点现已得到充分证实。它们在所有脊椎动物的胃肠道中大量存在，并已在包括肺、气管、膀胱、食管、眼睛、精囊以及可能的部分血管和中枢神经系统等多种其他器官中被识别出来。它们的超微结构特征和传递特性已为人所知，其生理作用至少在胃肠道中也开始被人们所理解。有证据表明，三磷酸腺苷（ATP）是从非肾上腺素能、非胆碱能（嘌呤能）神经释放的递质，这些证据包括：（a）神经中ATP的合成与储存；（b）神经受刺激时ATP的释放；（c）外源性应用的ATP模拟神经释放递质的作用，二者均使钾离子电导率特异性增加；（d）存在镁激活的ATP酶、5'-核苷酸酶和腺苷脱氨酶，这些酶可使ATP失活；（e）药物（包括2-取代咪唑啉、2,2'-吡啶异吲哚原和双嘧达莫），它们对外源性应用的ATP和神经刺激的反应产生类似的阻断或增强作用。
