Pteropodine and isopteropodine positively modulate the function of rat muscarinic M1 and 5-HT2 receptors expressed in Xenopus oocyte

摘要: Pteropodine and isopteropodine are heteroyohimbine-type oxindole alkaloid components of Uncaria tomentosa (Willd.) DC, a Peruvian medicinal plant known as cat's claw. In this study, the effects these alkaloids on function Ca(2+)-activated Cl(-) currents evoked by stimulation G protein-coupled muscarinic M(1) acetylcholine 5-HT(2) receptors were studied in Xenopus oocytes which rat cortex total RNA was translated. (1-30 microM) failed to induce membrane current themselves. However, markedly enhanced responses both 5-hydroxyhyptamine (5-HT) concentration-dependent reversible manner with maximal at 30 microM. produced 2.7- 3.3-fold increases response EC(50) values 9.52 9.92 microM, respectively, 2.4- 2.5-fold 5-HT 13.5 14.5 respectively. contrast, injected from cerebellum or spinal cord, neither had an effect metabotropic mediated glutamate receptor(1 5) (mGlu(1/5)) ionotropic N-methyl-D-aspartate, kainic acid glycine. (10 significantly reduced that elicited responses, but no 5-HT. On other hand, mitraphylline, stereoisomer pteropodine, modulate acetylcholine- 5-HT-induced responses. These results suggest pteropodine act positive modulators receptors.