Mupanomunda M M, Wang Y, Bukoski R D
Department of Internal Medicine, University of Texas Medical Branch, Galveston Island 77555, USA.
Am J Physiol. 1998 May;274(5):H1655-61. doi: 10.1152/ajpheart.1998.274.5.H1655.
We recently reported that Ca(2+)-induced relaxation could be linked to a Ca2+ receptor (CaR) present in perivascular nerves. The present study assessed the effect of chronic sensory denervation on Ca(2+)-induced relaxation. Mesenteric resistance arteries were isolated from rats treated as neonates with capsaicin (50 mg/kg), vehicle, or saline. The effect of cumulative addition of Ca2+ was assessed in vessels precontracted with 5 microM norepinephrine. Immunocytochemical studies showed that capsaicin treatment significantly reduced the density of nerves staining positively for calcitonin gene-related peptide (CGRP) and for the CaR (CGRP density: control, 51.1 +/- 3.9 microns2/mm2; capsaicin treated, 31.4 +/- 2.8 microns2/mm2, P = 0.01; control CaR density, 46 +/- 4 microns2/mm2, n = 7; capsaicin-treated CaR density, 24 +/- 4 microns2/mm2, n = 8, P = 0.002). Dose-dependent relaxation to Ca2+ (1-5 mM) was significantly depressed in vessels from capsaicin-treated rats (overall P < 0.001, n = 6 or 7), whereas the relaxation response to acetylcholine remained intact. These data support the hypothesis that Ca(2+)-induced relaxation is mediated by activation of the CaR associated with capsaicin-sensitive perivascular neurons.
我们最近报道，钙诱导的舒张可能与血管周围神经中存在的钙受体（CaR）有关。本研究评估了慢性感觉神经去神经支配对钙诱导舒张的影响。从新生期用辣椒素（50mg/kg）、赋形剂或生理盐水处理的大鼠中分离出肠系膜阻力动脉。在预先用5μM去甲肾上腺素预收缩的血管中评估钙的累积添加效应。免疫细胞化学研究表明，辣椒素处理显著降低了降钙素基因相关肽（CGRP）和CaR染色阳性的神经密度（CGRP密度：对照组，51.1±3.9μm²/mm²；辣椒素处理组，31.4±2.8μm²/mm²，P = 0.01；对照CaR密度，46±4μm²/mm²，n = 7；辣椒素处理组CaR密度，24±4μm²/mm²，n = 8，P = 0.002）。辣椒素处理的大鼠血管中对钙（1-5mM）的剂量依赖性舒张显著降低（总体P < 0.001，n = 6或7），而对乙酰胆碱的舒张反应保持完整。这些数据支持以下假设：钙诱导的舒张是由与辣椒素敏感的血管周围神经元相关的CaR激活介导的。
