Characteristics of membrane current induced by excitory amino acid receptors and the acting way of L-SOP

Key words: 
• Xenopus oocytes /
• mRNA /
• excitory amino acid /
• ionic glutamate receprots /
• metabotropic glutamate receptors

Abstract: Objective: To study the characters of membrane current of types of excitory amino acide and the acting way of TypeⅢmGluR（metabotropic glutamate receptor） agonist—L-SOP among them. Methods: A total receptor RNA was isolated from adult rat brain by acid guanidnium thiocyanate-phenol-chloroform（AGPC） method,mRNA was isolated from the total RNA by oligo（dT）-cellu- cose chromatography,and was then micro-injected into Xenopus oocytes to express,through a two-microeleetrode voltage clamp tech- nique.The ooeytes were refused with varieties of types of excitory amino acid. Results: 100μM KA（kainate） （ionic glutamate recep- tor） induced first a peak current and then a slowly descending current,which desentized at last.The mean maintained time was 37.57 min.2μM QA（quisqualate） （TYPEⅠmGluR） induced regulary calcium oscillation with a maintained time of （6.72±1.33） min. Both of the maintained time were shortened the agonist concentration increased.0.8 mM L-SOP of TYPEⅢmGluR agonist induced a kind of disciplinary oscillation with a maintained time of （20.17±8.47） min which was also shortened with an increasing concentra- tion,while the oscillation coule be antagonized by TYPEⅠmGluR antagonist—L-AP₃. Conclusion:: Each of these three types of gluta- mate amino acid receptors has its speuniquecial current mode when irritated;L-SOP is not only an agonist of TYPEⅢmGluR,but also a weak agonist of TYPEⅠ,that is,its acting way of producing oscillation is through TYPEⅠreceptor.