牛睫状动脉的非肾上腺素能非胆碱能血管舒张涉及降钙素基因相关肽和神经源性一氧化氮。

Nonadrenergic noncholinergic vasodilation in bovine ciliary artery involves CGRP and neurogenic nitric oxide.

作者信息

Wiencke A K, Nilsson H, Nielsen P J, Nyborg N C

机构信息

Department of Pharmacology, University of Aarhus, Denmark.

出版信息

Invest Ophthalmol Vis Sci. 1994 Jul;35(8):3268-77.

PMID:7519182

Abstract

PURPOSE

Characterization of the nonadrenergic noncholinergic (NANC) vasodilator innervation in the anterior segment in the bovine eye.

METHODS

The neurogenic tetrodotoxin-sensitive response to electrical field stimulation (EFS) of the intraocular segment of the bovine long posterior ciliary artery supplying the ciliary body was recorded using isolated ring segments of this artery mounted on an isometric myograph. After adrenergic and cholinergic receptor blockade (with phentolamine, propranolol, and atropine), the preconstricted vessels were subjected to EFS by passing constant current pulses (0.3 msec, 35 mA, 0.5 to 32 Hz) between two electrodes on either side of the vessel segments.

RESULTS

EFS resulted in 60% relaxation of the active tone in 40 vessels. Treatment with capsaicin reduced the NANC response by 16 +/- 2% (P < 0.001) and inhibition of the NO synthase with 1 x 10(-4) M L-NOARG reduced the NANC response by 83 +/- 10% (P < 0.001). Desensitization of the vessels to substance P had no effect. The CGRP(8-37) fragment (1 x 10(-6) M) in the presence of 1 x 10(-4) M L-NOARG reversibly and competitively inhibited the NANC response. L-arginine partly antagonized the inhibition induced by L-NOARG. About 60% of the L-NOARG-sensitive component of the NANC response was inhibited by methylene blue. Combined incubation with capsaicin and L-NOARG nearly abolished the NANC response. The L-NOARG-sensitive/capsaicin-resistant relaxation was present in endothelium denuded vessels. The responses to EFS were blocked by TTX.

CONCLUSIONS

The neurogenic NANC vasodilator response in the intraocular part of the bovine long posterior ciliary artery supplying the ciliary body is endothelium independent and consists of two components: a capsaicin-sensitive component mediated by CGRP released from sensory nerve endings and a larger L-NOARG sensitive component mediated by a direct "nitroxidergic" neurotransmission. The size of the nitroxidergic NANC response indicates that it has a physiological relevance in vivo.

摘要

目的

对牛眼前节非肾上腺素能非胆碱能（NANC）血管舒张神经支配进行特征描述。

方法

使用安装在等长肌动描记器上的牛眼长后睫状动脉眼内段的离体环段，记录对供应睫状体的该动脉眼内段电场刺激（EFS）的神经源性河豚毒素敏感反应。在肾上腺素能和胆碱能受体阻断后（使用酚妥拉明、普萘洛尔和阿托品），通过在血管段两侧的两个电极之间施加恒定电流脉冲（0.3毫秒，35毫安，0.5至32赫兹），对预收缩的血管进行EFS。

结果

EFS导致40条血管中的主动张力松弛60%。用辣椒素处理使NANC反应降低16±2%（P<0.001），用1×10⁻⁴M L-NOARG抑制一氧化氮合酶使NANC反应降低83±10%（P<0.001）。使血管对P物质脱敏没有效果。在存在1×10⁻⁴M L-NOARG的情况下，CGRP(8-37)片段（1×10⁻⁶M）可逆性且竞争性地抑制NANC反应。L-精氨酸部分拮抗L-NOARG诱导的抑制作用。NANC反应中约60%的L-NOARG敏感成分被亚甲蓝抑制。辣椒素和L-NOARG联合孵育几乎消除了NANC反应。L-NOARG敏感/辣椒素抗性松弛存在于内皮剥脱的血管中。对EFS的反应被TTX阻断。