Thompson G W, Collier K, Ardell J L, Kember G, Armour J A
Department of Physiology and Biophysics, Dalhousie University, Halifax, Nova Scotia, Canada B3H 4H7.
J Physiol. 2000 Nov 1;528(Pt 3):561-71. doi: 10.1111/j.1469-7793.2000.00561.x.
To determine the activity characteristics displayed by different subpopulations of neurons in a single intrinsic cardiac ganglionated plexus, the behaviour and co-ordination of activity generated by neurons in two loci of the right atrial ganglionated plexus (RAGP) were evaluated in 16 anaesthetized dogs during basal states as well as in response to increasing inputs from ventricular sensory neurites. These sub-populations of right atrial neurons received afferent inputs from sensory neurites in both ventricles that were responsive to local mechanical stimuli and the nitric oxide donor nitroprusside. Neurons in at least one RAGP locus were activated by epicardial application of veratridine, bradykinin, the beta1-adrenoceptor agonist prenaterol or glutamate. Epicardial application of angiotensin II, the selective beta2-adrenoceptor agonist terbutaline and selective alpha-adrenoceptor agonists elicited inconsistent neuronal responses. The activity generated by both populations of atrial neurons studied over 5 min periods during basal states displayed periodic coupled behaviour (cross-correlation coefficients of activities that reached, on average, 0.88 +/- 0.03; range 0.71-1) for 15-30 s periods of time. These periods of coupled activity occurred every 30-50 s during basal states, as well as when neuronal activity was enhanced by chemical activation of their ventricular sensory inputs. These results indicate that neurons throughout one intrinsic cardiac ganglionated plexus receive inputs from mechano- and chemosensory neurites located in both ventricles. That such neurons respond to multiple chemical stimuli, including those liberated from adjacent adrenergic efferent nerve terminals, indicates the complexity of the integrative processing of information that occurs within the intrinsic cardiac nervous system. It is proposed that the interdependent activity displayed by populations of neurons in different regions of one intrinsic cardiac ganglionated plexus, responding as they do to multiple cardiac sensory inputs, forms the basis for integrated regional cardiac control.
为了确定单个心脏内在神经节丛中不同神经元亚群所表现出的活动特征，在16只麻醉犬的基础状态下以及对心室感觉神经突增加的输入做出反应时，评估了右心房神经节丛（RAGP）两个位点的神经元产生的活动行为和协调性。这些右心房神经元亚群接受来自两个心室感觉神经突的传入输入，这些神经突对局部机械刺激和一氧化氮供体硝普钠有反应。至少一个RAGP位点的神经元可通过心外膜应用藜芦碱、缓激肽、β1肾上腺素能受体激动剂普瑞特罗或谷氨酸来激活。心外膜应用血管紧张素II、选择性β2肾上腺素能受体激动剂特布他林和选择性α肾上腺素能受体激动剂引起的神经元反应不一致。在基础状态下，对两个心房神经元群体在5分钟内产生的活动进行研究，结果显示在15 - 30秒的时间段内呈现周期性耦合行为（活动的互相关系数平均达到0.88±0.03；范围为0.71 - 1）。在基础状态下以及通过化学激活其心室感觉输入增强神经元活动时，这些耦合活动周期每30 - 50秒出现一次。这些结果表明，整个心脏内在神经节丛中的神经元接受来自位于两个心室的机械和化学感觉神经突的输入。这些神经元对多种化学刺激有反应，包括那些从相邻肾上腺素能传出神经末梢释放的刺激，这表明心脏内在神经系统内发生的信息整合处理具有复杂性。有人提出，一个心脏内在神经节丛不同区域的神经元群体所表现出的相互依赖活动，由于它们对多种心脏感觉输入做出反应，构成了整合区域心脏控制的基础。
