Study on double reciprocal innervation of the iris dilator muscle and sphincter muscle by a whole cell patch-clump technique

近年来的研究表明，虹膜扩张肌和括约肌都受到交感神经和副交感神经的双重支配。本研究用全细胞斑块技术研究虹膜肌细胞、扩张肌和括约肌的双向神经支配。在研究之前，我们培养了扩张器和括约肌细胞，以获得相当数量的同质材料。用免疫组织化学方法对肌细胞进行鉴定。培养的细胞表面比较平整，细胞膜比较脆弱。虽然它们并不完全适合实验，但我们记录了选定细胞的静息膜电位。动作电位低，0~-5 mV，电刺激不能记录动作电位。根据Watanabe等人(1)，在生理条件下，神经或直接电刺激括约肌结节不会引起任何膜电位的变化。它属于一种低兴奋性的平滑肌，如气管、主动脉和肺动脉。我们的结果似乎支持他们的结论。肌肉的低兴奋性是由于去极化(4，5)引起的内向电流(钙离子电流)和外向电流(K^+电流)之间的平衡。近年来，膜兴奋性在平滑肌中的多样性已为人们所知。虹膜平滑肌肉的性质与我们之前的假设截然不同。我们计划首先开发我们的主题，以研究虹膜肌肉细胞膜的钙电流。关于扩张肌，据我们所知，还没有关于斑块术的报道。

It is well-known that both the iris dilator muscle and the sphincter muscle are innervated doublely by the sympathetic and parasympathetic nerves by recent research applied the histochemical, pharmacological, physiological techniques. The purpose of this study is to investigate the double reciprocal innervation of the iris muscle cells, the dilator and the sphincter muscle by means of a whole cell patch-clump technique. Preceding the study we cultured the dilator and the sphincter cells to get considerable amonuts of the homogenous materials. Proof of the muscle cells was done with immunohistochemical method. The surface of the cultured cells was rather flat and the membrane was fragile. Although they were not fully suitable for the experiment, we recorded the resting membrane potential in the selected cells. It was found to be low, 0 to-5 mV.The action potential could not be record by the electrical stimulation. According to Watanabe et al (1) neither nerve nor direct electrical stimulation with short pulses of the sphincter nuscle elicited any changes in the membrane potential under physiological conditions. It belongs to a low-excitability smooth muscle such as the trachea, aorta and pulmonary artery. Our results appears to support their conclusion. The low-excitability of the muscle is due to the balance between the inward current (Ca^<2+> current) and the outward current (K^+ current) elicited by depolarization (4,5). Diversity of membrane excitability in smooth muscle has become recently known. The nature of the iris smooth muscles is quite different from what we previously assumed. We plan first to develop our theme for the investigation of Ca^<2+> current of the iris muscle cell membrane. Concerning the dilator muscle, as far as we know , there is no report on patch-clump technique.