Lundberg J M, Hemsén A, Rudehill A, Härfstrand A, Larsson O, Sollevi A, Saria A, Hökfelt T, Fuxe K, Fredholm B B
Department of Pharmacology, Karolinska Institutet, Stockholm, Sweden.
Neuroscience. 1988 Feb;24(2):659-72. doi: 10.1016/0306-4522(88)90359-4.
The localization of neuropeptide Y binding sites in the pig spleen, as revealed by [125I]Bolton-Hunter-labelled porcine neuropeptide Y and alpha 1-adrenergic receptor binding sites, as revealed by 125I-tetralone as radioligand, was compared with the distribution of neuropeptide Y and noradrenaline nerves, the latter revealed by tyrosine hydroxylase and dopamine-beta-hydroxylase, using immunohistochemistry. A large degree of codistribution was obtained between [125I]neuropeptide Y and alpha 1-binding sites in the capsule, trabeculae, blood vessels and the red pulp of the spleen. Neuropeptide Y and tyrosine hydroxylase as well as dopamine-beta-hydroxylase-positive nerves were identical in the spleen and had a similar gross distribution pattern as the [125I]neuropeptide Y and alpha 1 binding sites. In functional studies using the isolated blood-perfused spleen from pentobarbital-anaesthetized pigs, neuropeptide Y, noradrenaline and the alpha 1-selective agonist phenylephrine contracted the capsule and induced vasoconstriction in the spleen in vivo. However, the selective alpha 2-adrenoceptor agonists clonidine and azepexole had no effects on blood flow or perfusion pressure, suggesting that postjunctional alpha-receptors were of the alpha 1 type. Neuropeptide Y inhibited the forskolin-evoked, cyclic adenosine monophosphate formation in vitro. The [125I]neuropeptide Y binding, with an equilibrium-dissociation constant of 503 +/- 73 pM and a maximal number of specific binding sites of 23 +/- 3 fmol/mg protein, the neuropeptide Y-induced perfusion-pressure increase in vivo and the inhibition of forskolin-evoked cyclic adenosine monophosphate formation in vitro were dependent on the amidation of the C-terminal portion of the peptide molecule. Furthermore, the effects of neuropeptide Y were not changed by alpha- and beta-adrenoceptor blockade using prazosin and propranolol. Two weeks after postganglionic denervation the neuropeptide Y and the noradrenaline contents of the pig spleen were reduced by 97% and 99%, respectively. These changes were associated with a selective supersensitivity for the noradrenaline-induced perfusion-pressure increase in vivo compared with the effect of neuropeptide Y. However, a similar potentiation of the noradrenaline effect was induced by the monoamine-uptake blocker desipramine in the absence of denervation, and there was no change in the functional response to phenylephrine after denervation.(ABSTRACT TRUNCATED AT 400 WORDS)
用[125I]博尔顿-亨特标记的猪神经肽Y揭示猪脾脏中神经肽Y结合位点的定位，并用125I-四氢萘酮作为放射性配体揭示α1-肾上腺素能受体结合位点的定位，将其与神经肽Y和去甲肾上腺素能神经的分布进行比较，后者通过免疫组织化学法用酪氨酸羟化酶和多巴胺-β-羟化酶揭示。在脾脏的包膜、小梁、血管和红髓中，[125I]神经肽Y与α1-结合位点之间有很大程度的共分布。神经肽Y与酪氨酸羟化酶以及多巴胺-β-羟化酶阳性神经在脾脏中的分布相同，并且其大致分布模式与[125I]神经肽Y和α1-结合位点相似。在使用来自戊巴比妥麻醉猪的离体血液灌注脾脏的功能研究中，神经肽Y、去甲肾上腺素和α1-选择性激动剂苯肾上腺素使包膜收缩并在体内诱导脾脏血管收缩。然而，选择性α2-肾上腺素能受体激动剂可乐定和阿泽哌唑对血流量或灌注压没有影响，这表明节后α-受体为α1型。神经肽Y在体外抑制福斯可林诱发的环磷酸腺苷形成。[125I]神经肽Y结合的平衡解离常数为503±73 pM，最大特异性结合位点数为23±3 fmol/mg蛋白质，神经肽Y在体内诱导的灌注压升高以及在体外对福斯可林诱发的环磷酸腺苷形成的抑制取决于肽分子C末端部分的酰胺化。此外，使用哌唑嗪和普萘洛尔进行α-和β-肾上腺素能受体阻断后，神经肽Y的作用没有改变。节后去神经两周后，猪脾脏中神经肽Y和去甲肾上腺素的含量分别降低了97%和99%。这些变化与体内去甲肾上腺素诱导的灌注压升高相比神经肽Y的作用具有选择性超敏反应有关。然而，在没有去神经的情况下，单胺摄取阻滞剂地昔帕明也能诱导去甲肾上腺素作用的类似增强，而去神经后对苯肾上腺素的功能反应没有变化。（摘要截短于400字）
