Bernd P, Martinez H J, Dreyfus C F, Black I B
Department of Anatomy, Mount Sinai School of Medicine, New York, NY 10029.
Neuroscience. 1988 Jul;26(1):121-9. doi: 10.1016/0306-4522(88)90131-5.
Previous work has indicated that nerve growth factor specifically and selectively increases choline acetyltransferase and acetylcholinesterase in organotypic cultures of rat basal forebrain-medial septal area. To determine whether these actions are potentially receptor-mediated, organotypic and dissociated basal forebrain-medial septal area cultures were examined. Two independent methods, [125I]nerve growth factor binding and immunocytochemistry with a monoclonal nerve growth factor receptor antibody (192-IgG), detected specific receptors. The nerve growth factor receptors were localized to two different cellular populations: flat, large, non-neuron-like cells, and small, round, process-bearing, neuron-like cells. Dissociation studies with [125I]nerve growth factor suggested that high-affinity receptors were localized to the neuron-like population, while only low-affinity receptors were localized to the non-neuron-like cells. We tentatively conclude that nerve growth factor may elicit cholinergic effects by directly binding to high-affinity receptors on neurons. To begin examining receptor regulation, cultures were exposed to exogenous, unlabeled nerve growth factor continuously for 10 days before binding studies were performed. Prior exposure to nerve growth factor did not alter binding characteristics of the receptor, using the present methods.
先前的研究表明，神经生长因子能特异性且选择性地增加大鼠基底前脑-内侧隔区器官型培养物中的胆碱乙酰转移酶和乙酰胆碱酯酶。为了确定这些作用是否可能是由受体介导的，我们对器官型和分离的基底前脑-内侧隔区培养物进行了检查。两种独立的方法，即[125I]神经生长因子结合法和使用单克隆神经生长因子受体抗体（192-IgG）的免疫细胞化学法，检测到了特异性受体。神经生长因子受体定位于两种不同的细胞群体：扁平、大、非神经元样细胞，以及小、圆、有突起的神经元样细胞。用[125I]神经生长因子进行的解离研究表明，高亲和力受体定位于神经元样群体，而只有低亲和力受体定位于非神经元样细胞。我们初步得出结论，神经生长因子可能通过直接与神经元上的高亲和力受体结合来引发胆碱能效应。为了开始研究受体调节，在进行结合研究之前，将培养物连续10天暴露于外源性未标记的神经生长因子。使用目前的方法，预先暴露于神经生长因子不会改变受体的结合特性。
