Nukina I, LaBella F S
J Neurochem. 1987 Aug;49(2):389-92. doi: 10.1111/j.1471-4159.1987.tb02877.x.
Cerebral cortical slices from rat brain were incubated at 37 degrees C for 2 h in the presence of isoproterenol, noradrenaline, or adrenaline, and binding affinities and densities of adrenoceptor subtypes were subsequently examined in homogenized tissue. The density of alpha 2- and total beta-adrenoceptors was estimated using the radioligands [3H]rauwolscine and [3H]dihydroalprenolol (DHA), respectively. The percentages of beta 1- and beta 2-adrenoceptors were defined by inhibiting the binding of [3H]DHA with the beta 1-selective antagonist metoprolol. Exposure of slices to noradrenaline and adrenaline significantly decreased the maximal number of binding sites (Bmax) of alpha 2-adrenoceptors (48 and 37% respectively) without significantly affecting affinity; isoproterenol had no effect. Exposure to isoproterenol, noradrenaline, and adrenaline significantly decreased the Bmax of beta-adrenoceptors (by 60, 34, and 24%, respectively) but did not affect the affinity. Isoproterenol and adrenaline significantly decreased the density of beta 1-adrenoceptors by 75 and 24% and beta 2-adrenoceptors by 23 and 28%, respectively. Noradrenaline significantly decreased the density of beta 1-adrenoceptors by 42% without affecting the number of beta 2-adrenoceptors. These findings indicate that subtypes of adrenoceptors in rat cerebral cortex are differentially regulated by adrenergic agonists.
将大鼠大脑的大脑皮质切片在37℃下于异丙肾上腺素、去甲肾上腺素或肾上腺素存在的条件下孵育2小时，随后在匀浆组织中检测肾上腺素能受体亚型的结合亲和力和密度。分别使用放射性配体[3H]育亨宾和[3H]二氢心得舒（DHA）估计α2 -和总β -肾上腺素能受体的密度。β1 -和β2 -肾上腺素能受体的百分比通过β1 -选择性拮抗剂美托洛尔抑制[3H]DHA的结合来定义。将切片暴露于去甲肾上腺素和肾上腺素可显著降低α2 -肾上腺素能受体的最大结合位点数（Bmax）（分别为48%和37%），而不显著影响亲和力；异丙肾上腺素无作用。暴露于异丙肾上腺素、去甲肾上腺素和肾上腺素可显著降低β -肾上腺素能受体的Bmax（分别降低60%、34%和24%），但不影响亲和力。异丙肾上腺素和肾上腺素分别使β1 -肾上腺素能受体的密度显著降低75%和24%，使β2 -肾上腺素能受体的密度分别降低23%和28%。去甲肾上腺素使β1 -肾上腺素能受体的密度显著降低42%，而不影响β2 -肾上腺素能受体的数量。这些发现表明大鼠大脑皮质中肾上腺素能受体亚型受肾上腺素能激动剂的调节存在差异。
