Wells D G, Mawe G M
Department of Anatomy and Neurobiology, College of Medicine, University of Vermont, Burlington 05405.
Am J Physiol. 1993 Aug;265(2 Pt 1):G258-69. doi: 10.1152/ajpgi.1993.265.2.G258.
Intracellular recordings and dye injections were used to investigate neurons located in ganglia of the sphincter of Oddi (SO) region in guinea pigs. Four types of neurons were encountered based on physiological properties. The two most abundant types, tonic and phasic, had similar membrane characteristics and morphologies but yet could be differentiated by their spiking characteristics. Tonic cells spiked throughout a depolarizing current pulse and were sometimes spontaneously active. Phasic cells fired only a single action potential at the onset of a current pulse regardless of stimulus amplitude or duration. Both tonic and phasic cells had Dogiel type I morphologies. They typically had a single long process and several very short processes emanating from the soma. NADPH diaphorase activity was demonstrated in cells with similar morphologies, indicating that nitric oxide may be an intrinsic transmitter in some of these cells. Cells with a prolonged afterhyperpolarization (AH cells), similar to the type 1/AH cells of the gut, were rarely encountered. This finding was consistent with the observation that very few calbindin D-immunoreactive neurons exist in this region. Action potentials could not be generated in the fourth type of neuron, called nonspiking neurons, even though they did receive synaptic input. Most tonic and phasic cells received at least one nicotinic fast excitatory postsynaptic potential (EPSP). In addition, both slow EPSPs and inhibitory postsynaptic potentials were observed. Most AH cells received only slow excitatory synaptic input.
采用细胞内记录和染料注射技术研究豚鼠Oddi括约肌（SO）区域神经节中的神经元。根据生理特性，发现了四种类型的神经元。两种最常见的类型，即紧张性和相位性神经元，具有相似的膜特性和形态，但可通过其放电特性加以区分。紧张性细胞在去极化电流脉冲期间持续放电，有时还会自发活动。相位性细胞在电流脉冲开始时仅发放单个动作电位，而与刺激幅度或持续时间无关。紧张性和相位性细胞均具有Dogiel I型形态。它们通常有一个单一的长突起和几个从胞体发出的非常短的突起。在形态相似的细胞中发现了NADPH黄递酶活性，表明一氧化氮可能是其中一些细胞的内源性递质。很少遇到具有延长的超极化后电位的细胞（AH细胞），类似于肠道中的1型/AH细胞。这一发现与该区域存在极少的钙结合蛋白D免疫反应性神经元的观察结果一致。在第四种类型的神经元（称为非放电神经元）中无法产生动作电位，尽管它们确实接受突触输入。大多数紧张性和相位性细胞至少接受一个烟碱型快速兴奋性突触后电位（EPSP）。此外，还观察到慢EPSP和抑制性突触后电位。大多数AH细胞仅接受慢兴奋性突触输入。
