Marazziti D, Rossi A, Masala I, Rotondo A, Palego L, Mazzoni M, Giannaccini G, Lucacchini A, Cassano G B
Dipartimento di Psichiatria, Neurobiologia, Farmacologia e Biotecnologie, University of Pisa, Italy.
Biol Psychiatry. 1999 Feb 15;45(4):443-7. doi: 10.1016/s0006-3223(98)00055-9.
Some data show that different factors may influence the serotonin (5-HT) uptake rate. Our study aimed at evaluating the possible role of a protein kinase C (PKC) activator, i.e., 4-beta-12-tetradecanoylphorbol-13-acetate (beta-TPA) on the platelet 5-HT uptake of young and elderly subjects, through the measurement of the 5-HT uptake itself and 3H-paroxetine ([3H]PAR) binding sites, which correspond to the transporter protein.
Human platelets and 5-HT uptake were evaluated according to the method of Arora and Meltzer, while [3H]PAR binding was performed following the Marazziti et al method.
The results showed that beta-TPA reduced significantly the maximal velocity (Vmax) of 5-HT uptake, with no change in the Michaelis constant or in [3H]PAR binding parameters, in platelets of both young and elderly subjects. Although this last group of subjects had a significantly lower Vmax than the other, the degree of inhibition was almost the same (75%) in both.
These findings indicate that PKC decreases the 5-HT uptake rate by modifying the phosphorylation state of the transporter and with no change in the number of [3H]PAR binding sites. The responsiveness of this pathway is identical in both young and elderly subjects.
一些数据表明不同因素可能影响血清素（5-羟色胺，5-HT）摄取率。我们的研究旨在通过测量5-HT摄取本身以及与转运蛋白相对应的3H-帕罗西汀（[3H]PAR）结合位点，评估蛋白激酶C（PKC）激活剂，即4-β-12-十四酰佛波醇-13-乙酸酯（β-TPA）对年轻和老年受试者血小板5-HT摄取的可能作用。
根据Arora和Meltzer的方法评估人血小板和5-HT摄取，而[3H]PAR结合则按照Marazziti等人的方法进行。
结果显示，β-TPA显著降低了年轻和老年受试者血小板中5-HT摄取的最大速度（Vmax），米氏常数或[3H]PAR结合参数无变化。尽管后一组受试者的Vmax明显低于另一组，但两组的抑制程度几乎相同（75%）。
这些发现表明，PKC通过改变转运蛋白的磷酸化状态降低5-HT摄取率，且[3H]PAR结合位点数量无变化。该途径在年轻和老年受试者中的反应性相同。
