Park B K, Cho E S, Lee J D, Oh C, Lee M S, Kim S Z, Kim S H, Cho K W
Department of Oral Anatomy, School of Dentistry and Institute for Dental Sciences, Department of Anatomy, Republic of Korea.
Arch Oral Biol. 1998 Aug;43(8):611-8. doi: 10.1016/s0003-9969(98)00039-9.
Atrial natriuretic peptide (ANP) receptors were characterized in rat oral mucosa using quantitative in vitro autoradiography and activation of particulate guanylyl cyclase (GC) by natriuretic peptides. Competition-binding analysis performed by quantitative in vitro autoradiography demonstrated specific [125I]rANP(1-28) binding sites in the tongue and hard palate. The precise location of this binding was revealed on the basal and parabasal cells of the epithelia by microautoradiography. The dissociation constant (Kd) and maximal binding capacity (Bmax) of these sites were 3.34+/-1.35 nM and 2.71+/-2.21 fmol/mm2 on the epithelium of the tongue, and 4.09+/-1.52 nM and 3.45+/-3.01 fmol/mm2 on the epithelium of the hard palate, respectively. Receptor subtypes were characterized by competition with des [Gln18, Ser19, Gly20, Leu21, Gly22] ANP(4-23) (C-ANP), a specific ligand for the clearance receptor (NPR-C). These binding sites were displaced by C-ANP with inhibition constant (Ki) of 8.96+/-3.18 nM and Bmax of 2.89+/-2.45 fmol/mm2 on the epithelium of the tongue, and Ki of 9.12+/-2.71 nM and Bmax of 3.08+/-2.94 fmol/mm2 on the epithelium of the hard palate, respectively. Production of cyclic GMP by particulate GC in the epithelial membranes of the tongue and hard palate was stimulated by rANP(1-28), porcine brain natriuretic peptide (BNP)(1-26), and C-type natriuretic peptide (CNP)(1-22) in a dose-dependent manner. These results indicate that ANP-binding sites in the epithelium of the tongue and hard palate are mainly clearance receptors (NPR-C) but biological receptors (NPR-A and/or NPR-B) with GC activity are also present, and suggest that ANP may have a role in the proliferation of the oral epithelial cells, especially in the tongue and hard palate.
利用定量体外放射自显影技术以及利钠肽对颗粒型鸟苷酸环化酶（GC）的激活作用，对大鼠口腔黏膜中的心房利钠肽（ANP）受体进行了特性研究。通过定量体外放射自显影进行的竞争结合分析表明，在舌和硬腭中存在特异性的[125I]rANP(1 - 28)结合位点。显微放射自显影显示该结合位点位于上皮的基底细胞和副基底细胞上。这些位点在舌上皮的解离常数（Kd）和最大结合容量（Bmax）分别为3.34±1.35 nM和2.71±2.21 fmol/mm2，在硬腭上皮分别为4.09±1.52 nM和3.45±3.01 fmol/mm2。通过与去[Gln18, Ser19, Gly20, Leu21, Gly22]ANP(4 - 23)（C - ANP，清除受体（NPR - C）的特异性配体）竞争来鉴定受体亚型。这些结合位点在舌上皮被C - ANP取代，抑制常数（Ki）为8.96±3.18 nM，Bmax为2.89±2.45 fmol/mm2；在硬腭上皮Ki为9.12±2.71 nM，Bmax为3.08±2.94 fmol/mm2。舌和硬腭上皮膜中的颗粒型GC产生环磷酸鸟苷（cGMP）受到rANP(1 - 28)、猪脑利钠肽（BNP）(1 - 26)和C型利钠肽（CNP）(1 - 22)的剂量依赖性刺激。这些结果表明，舌和硬腭上皮中的ANP结合位点主要是清除受体（NPR - C），但也存在具有GC活性的生物受体（NPR - A和/或NPR - B），并提示ANP可能在口腔上皮细胞尤其是舌和硬腭的增殖中发挥作用。
