Huszti Z, Magyar K
Agents Actions. 1985 Apr;16(3-4):240-3. doi: 10.1007/BF01983150.
Under the total blockade of PDE1 and the presence of endogeneous ATP and MgCl2, the inhibitory effect of cAMP on HD activity could be demonstrated as low as 8.7 X 10(-8) M concentration in a 20,000 g supernatant of a sustained homogenate of rat hypothalamus. A total reverse of this action and also a partial release of the cAMP-induced inhibition of HD, occurred at higher concentrations of cAMP, and ATP could be achieved by an endogeneous inhibitor of cAMP-dependent protein kinase or by cyclic GMP. The reversal of cAMP action by PKI seems to serve a strong evidence for the role of cAMP-dependent protein kinase (EC 2.7.37: ATP-protein phosphotransferase) in this action and emphasized the involvement of a direct or an indirect phosphorylation in the regulation of HD activity. The stimulatory effect of cyclic GMP on cAMP-induced inhibition of HD or its 'direct' effect on histamine formation is asserted, probably through the activation of PDE, or through independent stimulatory machinery, coupled to the cyclic GMP system.
在磷酸二酯酶1（PDE1）完全被阻断且存在内源性三磷酸腺苷（ATP）和氯化镁（MgCl2）的情况下，在大鼠下丘脑持续匀浆的20,000g上清液中，低至8.7×10^(-8)M浓度的环磷酸腺苷（cAMP）对组胺脱羧酶（HD）活性的抑制作用就能得到证实。在较高浓度的cAMP时，这种作用会完全逆转，并且cAMP诱导的对HD的抑制也会部分解除，通过cAMP依赖性蛋白激酶的内源性抑制剂或环鸟苷酸（cGMP）可实现ATP的这种效果。蛋白激酶抑制剂（PKI）对cAMP作用的逆转似乎有力地证明了cAMP依赖性蛋白激酶（EC 2.7.37：ATP - 蛋白质磷酸转移酶）在这一作用中的角色，并强调了直接或间接磷酸化参与了对HD活性的调节。环鸟苷酸对cAMP诱导的HD抑制的刺激作用或其对组胺形成的“直接”作用被认为可能是通过磷酸二酯酶的激活，或者通过与环鸟苷酸系统偶联的独立刺激机制实现的。
