Butryn R K, Ruan H, Hull C M, Frank R N
Kresge Eye Institute, Wayne State University School of Medicine, Detroit, Michigan 48201, USA.
Microvasc Res. 1995 Jul;50(1):80-93. doi: 10.1006/mvre.1995.1040.
The pericytes of the retinal capillaries are considered to be contractile cells, based on indirect evidence. We attempted to detect pericyte contractility directly using a morphometric method following intravitreal injection of vasoconstricting (endothelin-1, norepinephrine) and vasodilating (forskolin, prostaglandin E1) agonists in rats. The technique involved measuring changes in the ratio of the (lumenal perimeter x mean lumenal radius) to the lumenal area (rP/A ratio, which we defined as "caliber"). Following intravitreal injection of endothelin-1 or norepinephrine there is an ophthalmoscopically visible constriction of the larger retinal arterioles. This constriction is also clearly demonstrable morphometrically (P = 0.001 for endothelin-1 and P = 0.047 for norepinephrine). However, neither for the vasoconstricting nor for the vasodilating agonists is there evidence of a significant change of the caliber of the capillaries. At least in the retina of the rat, therefore, we have no evidence that the pericytes perform a contractile function that alters flow in the capillaries.
基于间接证据，视网膜毛细血管周细胞被认为是收缩性细胞。我们试图通过形态测量法直接检测周细胞的收缩性，该方法是在大鼠玻璃体内注射血管收缩剂（内皮素 -1、去甲肾上腺素）和血管舒张剂（福斯高林、前列腺素E1）后进行的。该技术包括测量（管腔周长×平均管腔半径）与管腔面积的比值变化（rP/A比值，我们将其定义为“管径”）。玻璃体内注射内皮素 -1或去甲肾上腺素后，在检眼镜下可见较大的视网膜小动脉收缩。这种收缩在形态测量上也很明显（内皮素 -1的P = 0.001，去甲肾上腺素的P = 0.047）。然而，无论是血管收缩剂还是血管舒张剂，都没有证据表明毛细血管管径有显著变化。因此，至少在大鼠视网膜中，我们没有证据表明周细胞具有改变毛细血管血流的收缩功能。
