Cherry J A, Thompson B E, Pho V
Department of Psychology and Laboratory of Molecular Neurobiology and Behavior, 64 Cummington Street, Boston University, 02215, Boston, MA, USA.
Biochim Biophys Acta. 2001 Mar 19;1518(1-2):27-35. doi: 10.1016/s0167-4781(01)00164-6.
Cyclic AMP is hydrolyzed by members of at least eight classes of cyclic nucleotide phosphodiesterases (PDEs). Although it has been reported that cyclic AMP PDE activity in mammalian tissues can be inhibited by benzodiazepines, it has not been conclusively demonstrated that members of the class of cyclic AMP-specific, rolipram-inhibitable PDEs (PDE4s) are targets for these drugs. Moreover, no PDE4s expressed in mice have been characterized. To address these issues, we isolated two cDNAs representing homologues of PDE4A1 and PDE4B3 from a mouse brain library. After transient transfection in human embryonic kidney (HEK) 293 cells, the mouse PDEs hydrolyzed cyclic AMP with a low K(m) and were inhibited by rolipram; both are properties typical of other mammalian PDE4 enzymes. In addition, we found that diazepam inhibited cyclic AMP hydrolysis by the mouse PDE4 subtypes. Interestingly, PDE4B was significantly more sensitive to inhibition by both rolipram and diazepam than the PDE4A subtype. This is the first demonstration that recombinantly expressed PDE4s are inhibited by diazepam, and should facilitate future studies with mouse models of depression and anxiety.
环磷酸腺苷（cAMP）可被至少八类环核苷酸磷酸二酯酶（PDEs）水解。尽管有报道称哺乳动物组织中的环磷酸腺苷磷酸二酯酶活性可被苯二氮䓬类药物抑制，但尚未确凿证明环磷酸腺苷特异性、咯利普兰可抑制的磷酸二酯酶（PDE4s）家族成员是这些药物的作用靶点。此外，尚未对小鼠中表达的PDE4s进行表征。为解决这些问题，我们从小鼠脑文库中分离出两个代表PDE4A1和PDE4B3同源物的cDNA。在人胚肾（HEK）293细胞中瞬时转染后，小鼠PDEs以低K（m）水解环磷酸腺苷，并被咯利普兰抑制；这两者都是其他哺乳动物PDE4酶的典型特性。此外，我们发现地西泮可抑制小鼠PDE4亚型对环磷酸腺苷的水解。有趣的是，PDE4B对咯利普兰和地西泮抑制的敏感性明显高于PDE4A亚型。这是首次证明重组表达的PDE4s可被地西泮抑制，这将有助于未来对抑郁症和焦虑症小鼠模型的研究。
