嗜热四膜虫中的吞噬作用：阿片类药物对纳洛酮可逆性抑制作用。

Phagocytosis in Tetrahymena thermophila: naloxone-reversible inhibition by opiates.

De Jesus S, Renaud F L

Biology Department, University of Puerto Rico, Rio Piedras 00931.

Comp Biochem Physiol C Comp Pharmacol Toxicol. 1989;92(1):139-42. doi: 10.1016/0742-8413(89)90216-8.

Abstract

Nanomolar concentrations of opiates inhibit phagocytosis in the ciliated protozoan Tetrahymena thermophila. 2. Naloxone and naltrexone counteract the effect of the opiate agonists tested. 3. The dose-response curves are U-shaped, with no detectable effect at low or high concentrations. 4. An increase in extracellular calcium and dopamine counteract the inhibition caused by metenkephalin. 5. The recognition mechanism for opiates in Tetrahymena cannot be classified as belonging to any of the mammalian opiate receptor subtypes and is perhaps a primitive receptor.

摘要

纳摩尔浓度的阿片类物质会抑制嗜热栖热四膜虫这种纤毛原生动物的吞噬作用。2. 纳洛酮和纳曲酮可抵消所测试的阿片类激动剂的作用。3. 剂量反应曲线呈U形，在低浓度或高浓度时未检测到作用。4. 细胞外钙和多巴胺的增加可抵消甲硫氨酸脑啡肽引起的抑制作用。5. 四膜虫中阿片类物质的识别机制不能归类为任何一种哺乳动物阿片受体亚型，可能是一种原始受体。