Different roles of IP4 and IP3 in the signal pathway coupled to the TRH receptor in microinjected Xenopus oocytes

FEBS Letters

Schwarz, Jürgen R.¹  Meyerhof, Wolfgang²  Mahlmann, Stefan¹ 

[1] Physiologisches Institut, Universitätskrankenhaus Eppendorf, Martinistraße 52, D-2000 Hamburg 20, FRG;Institut für Zellbiochemie und klinische Neurobiologie, Martinistraße 52, D-2000 Hamburg 20, FRG

关键词: Thyrotropin-releasing hormone;    Hormone receptor;    Chloride current;    Voltage clamp;    Inositol 1;    4;    5-trisphosphate;    Inositol 1;    3;    4;    5-tetrakisphosphate;    (Xenopus oocyte);   

DOI  :  10.1016/0014-5793(89)80026-2

学科分类：生物化学/生物物理

来源: John Wiley & Sons Ltd.

【 摘 要 】

Different effects of injected IP₄ and IP₃, on membrane Cl⁻ currents were observed in Xenopus oocytes previously microinjected with GH₃, cell poly(A)⁺ RNA. IP₃ induced a biphasic current response similar to that induced by TRH, whereas IP₄ regularly evoked a monophasic current response consisting of a prolonged inward current with superimposed oscillations. Membrane currents elicited by TRH were enhanced by prior injection of IP₄, but not of IP₃. In contrast to IP₃-induced membrane currents, those evoked by IP₄ were independent of injection depth. Phorbol ester led to enhancement of the initial current after injection of IP₃, whereas the current oscillations were greater following injection of IP₄. The results indicate that, in Xenopus oocytes, IP₄ plays a role different from that of IP₃ within the signal transduction pathway initiated by ligand stimulation of a neuropeptide receptor.

【 授权许可】

Unknown