PRESYNAPTIC ADENOSINE A(2A) RECEPTORS ON SOMA AND CENTRAL TERMINALS OF RAT VAGAL AFFERENT NEURONS
PRESYNAPTIC ADENOSINE A(2A) RECEPTORS ON SOMA AND CENTRAL TERMINALS OF RAT VAGAL AFFERENT NEURONS
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DOI：
10.1016/0006-8993(94)90327-1
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发表时间：
1994-07-25
期刊：
影响因子：
2.9
通讯作者：
JARROTT, B
中科院分区：
文献类型：
--
作者：
CASTILLOMELENDEZ, M;KRSTEW, E;JARROTT, B
延髓的背侧迷走神经复合体是参与调节多种自主功能（包括心血管控制）的关键中心。腺苷被认为是压力感受器反射的潜在神经调节剂，因此当前的研究调查了大鼠迷走神经传入神经元上腺苷受体的存在和特征。在结节-迷走神经油脂间隙制备中，腺苷 A(2a) 激动剂 CGS-21680 仅在选择性腺苷 A(1) 拮抗剂 PACPX 存在的情况下才会引起去极化。使用 [H-3]NECA (4 nM) 抑制 A(1) 结合的放射自显影技术首次实现了孤束核 (NTS) 中高亲和力腺苷 A(2) 受体的可视化。与假手术对照相比，单侧结节性神经节切除术导致病变（同侧）NTS 中的结合减少了 90% 以上。此外，通过体内微透析测量，局部施用 CGS-21680 增加了 NTS 中诱发的谷氨酸释放。这些数据表明，大鼠迷走神经传入神经元的胞体和中央末端均存在突触前腺苷 A(2a) 受体，从而支持腺苷可能在压力感受器反射中具有调节作用的假设。
The dorsal vagal complex of the medulla oblongata is a key centre involved in the regulation of numerous autonomic functions, including cardiovascular control. Adenosine has been implicated as a potential neuromodulator of the baroreceptor reflex, and therefore the current study has investigated the presence and characteristics of adenosine receptors on rat vagal afferent neurons. In the nodose-vagal grease gap preparation, the adenosine A(2a) agonist CGS-21680 evoked a depolarisation only in the presence of the selective adenosine A(1) antagonist PACPX. Autoradiography using [H-3]NECA (4 nM) with suppression of A(1) binding enabled the first visualisation of high affinity adenosine A(2) receptors in the nucleus tractus solitarius (NTS). Unilateral nodose ganglionectomy resulted in over 90% reduction in binding in the lesioned (ipsilateral) NTS compared to a sham control. Furthermore, local administration of CGS-21680 increased evoked glutamate release in the NTS, as measured by in vivo microdialysis. These data suggest the presence of presynaptic adenosine A(2a) receptors on both the soma and central terminals of rat vagal afferent neurons, and thereby support the hypothesis that adenosine may have a modulatory role in the baroreceptor reflex.