Coronas V, Srivastava L K, Liang J J, Jourdan F, Moyse E
Laboratoire de Physiologie Neurosensorielle, CNRS, Université Claude Bernard, Villeurbanne, France.
J Chem Neuroanat. 1997 May;12(4):243-57. doi: 10.1016/s0891-0618(97)00215-9.
Olfactory bulb (OB) of mammals contains a large population of dopaminergic interneurons within the glomerular layer. Dopamine has been shown in vivo to modulate several aspects of olfactory information processing. The dopamine receptors of olfactory bulb and mucosa are assessed here at the levels of mRNAs and radioligand binding sites with presently available tools. D1A mRNA was found in OB glomerular-, plexiform-, mitral-cell and granular layers, but not in olfactory mucosa. D1B mRNA was absent in olfactory bulb and mucosa. D1-like binding sites were detected with two distinct radioligands, in glomerular-, plexiform-, mitral cell- and granular layers of OB but not in olfactory mucosa. We thus demonstrate the previously doubtful presence of D1-like receptors in OB. D2 mRNAs were localized in the glomerular and granular layers of OB and in olfactory mucosa; lesser amounts of D3 mRNAs were found in OB glomerular and granular layer, but not in olfactory mucosa. No D4 mRNA was detected in either structure. High densities of D2-like, [125I]Iodosulpride-labelled binding sites, were revealed within lamina propria of olfactory mucosa, and confirmed in the olfactory nerve- and glomerular layers of OB. A faint but significant density of [3H]7-hydroxy-dipropyl-aminotetralin (OH-DPAT) labelled, D3 binding sites was detected in olfactory nerve- and glomerular layers of OB, but not in olfactory mucosa. Competition of [125I]Iodosulpride specific binding by three D2/D3 selective drugs yielded kinetics typical of the D2 receptor subtype in olfactory bulb and mucosa. Olfactory nerve- and glomerular layers of OB are proved thus to contain a predominant contingent of D2 receptors and a minor population of D3 receptors, while olfactory mucosa expresses only D2 receptors.
哺乳动物的嗅球（OB）在肾小球层内含有大量多巴胺能中间神经元。多巴胺已在体内被证明可调节嗅觉信息处理的多个方面。本文使用现有工具在mRNA和放射性配体结合位点水平评估嗅球和黏膜中的多巴胺受体。发现D1A mRNA存在于OB的肾小球层、丛状层、二尖瓣细胞层和颗粒层，但在嗅觉黏膜中不存在。D1B mRNA在嗅球和黏膜中均不存在。用两种不同的放射性配体检测到D1样结合位点，存在于OB的肾小球层、丛状层、二尖瓣细胞层和颗粒层，但在嗅觉黏膜中不存在。因此，我们证实了OB中以前存疑的D1样受体的存在。D2 mRNA定位于OB的肾小球层和颗粒层以及嗅觉黏膜中；在OB的肾小球层和颗粒层中发现了少量的D3 mRNA，但在嗅觉黏膜中未发现。在这两种结构中均未检测到D4 mRNA。在嗅觉黏膜固有层中发现了高密度的D2样、[125I]碘舒必利标记的结合位点，并在OB的嗅神经层和肾小球层中得到证实。在OB的嗅神经层和肾小球层中检测到了微弱但显著密度的[3H]7-羟基-二丙基-氨基四氢萘（OH-DPAT）标记的D3结合位点，但在嗅觉黏膜中未检测到。三种D2/D3选择性药物对[125I]碘舒必利特异性结合的竞争在嗅球和黏膜中产生了典型的D2受体亚型动力学。因此，证明OB的嗅神经层和肾小球层主要含有D2受体，少量含有D3受体，而嗅觉黏膜仅表达D2受体。
