Electron Microscope Autoradiographic Study on Brain Gut Peptide Uptake by Platelets

血小板和动脉瘤间存在着多种形态、生化和药理上的相似之处，这些细胞一般不被算作神经元，但可以认为与神经元有关。由于已经证实在动脉瘤旁存在多种胺和脑肠肽，因此应该预料到血小板能够储存神经肽。为了验证这一假说，我们用放射自显影技术研究了兔血小板和巨核细胞体外摄取和储存~3H标记脑肠肽的情况。用~3H-血管紧张素II、~3H-神经肽Y、~3H-加压素和~3H-物质P四种放射化学物质。血浆和骨髓组织中的血小板悬液在Eagle‘s培养液中与5个微量CI在37ﾟC孵育60min。光镜放射自显影显示巨核细胞摄取~3H-血管紧张素II。电子显微镜放射自显影也证实了血小板摄取~3H-血管紧张素II。银粒优先与致密的血小板结合，这也是儿茶酚胺的储存场所。巨核细胞和血小板对~3H-神经肽Y和~3H-P物质均无明显摄取，巨核细胞与~3H-加压素孵育后有轻微标记。放射自显影分析也用来阐明亚哺乳动物的血栓细胞是否能在体外摄取~3H-Agniotensin II。在鸡中证实了同位素的摄取，但在青蛙中没有证实。

Multiple Morphological, Biochemical and Pharmacological Similarities Exist Between Blood Platelets and Paraneurons Which are Cells Generally Have not Been Counted as Neurons and Yet can be Regarded as Related to Neurons. It Should be Expected That Platelets Would be Able to Store Neuropeptides, Since The Coexistence of Multiple Amines and Brain Gut Peptides in The Paraneuron has Been Demonstrated. To Verify This Hypothesis, we Examined the Uptake and Storage of ^3H-Labeled Brain Gut Peptides by Rabbit Platelets and Megakaryocytes in Vitro Using Autoradiographic Techniques. The Following Radiochemicals Were Used : ^3H-Angiotensin II, ^3H-Neuropeptide Y, ^3H-Vasopressin and ^3H-Substance P. Suspensions of Platelets in Plasma and Bone Marrow Tissues in Eagle's Medium Were Incubated With 5 Micro CI of Each Isotope for 60 Min at 37ﾟ C. A Light Microscopic Autoradiography has Revealed The Active Uptake of ^3H-Angiotensin II by Megakaryocytes. ^3H-Angiotensin II Uptake by Platelets Has Also Confirmed by Electron Microscopic Autoradiography. Silver Grains Are Preferentially Associated With Dense Bodies of Platelets Which are Also the Storage Sites of Catecholamines. Neither Megakaryocytes Nor Platelets Show any Active Uptake of ^3H-Neuropeptide Y and ^3H-Substance P. Megakaryocytes are Slightly Labeled After Incubation with ^3H-Vasopressin. Autoradiographic Analysis Has Also Performed to Clarify Whether or not Submammalian Thrombocytes can Take up in Vitro ^3H-Agniotensin II. The Uptake of the Isotope is Confirmed in Chicken, but not in Frog.