Effect of Mg2+ on guanine nucleotide sensitivity of ligand binding to serotonin1A receptors from bovine hippocampus.
The serotonin1A (5-HT1A) receptor is an important member of the superfamily of seven transmembrane domain G-protein coupled receptors (GPCRs). We report here that guanine nucleotide sensitivity of agonist binding to hippocampal 5-HT1A receptors is dependent on the concentration of Mg2+. Our results show that agonist binding to 5-HT1A receptors is relatively insensitive to guanine nucleotides in the absence of Mg2+. In contrast to this, the specific antagonist binding is insensitive to guanine nucleotides, even in the presence of Mg2+. These results point out the requirement of an optimal concentration of Mg2+ which could be used in assays toward determining guanine nucleotide sensitivity of ligand binding to GPCRs such as the 5-HT1A receptor. Our results provide novel insight into the requirement and concentration dependence of Mg2+ in relation to guanine nucleotide sensitivity for the 5-HT1A receptor in particular, and GPCRs in general.
Kalipatnapu
Shanti
S
Centre for Cellular and Molecular Biology, Uppal Road, Hyderabad 500 007, India.
Jafurulla
Md
M
Chandrasekaran
Nandhini
N
Chattopadhyay
Amitabha
A
D017371:8-Hydroxy-2-(di-n-propylamino)tetralin / Q000493:pharmacokinetics*; D000818:Animals; D001665:Binding Sites; D002417:Cattle; D002478:Cells, Cultured; D004305:Dose-Response Relationship, Drug; D006147:Guanine / Q000378:metabolism*; D006624:Hippocampus / Q000000981:diagnostic imaging / Q000187:drug effects* / Q000378:metabolism*; D008024:Ligands; D015636:Magnesium Chloride / Q000493:pharmacokinetics*; D011485:Protein Binding / Q000187:drug effects; D011877:Radionuclide Imaging; D019275:Radiopharmaceuticals / Q000493:pharmacokinetics; D044302:Receptor, Serotonin, 5-HT1B / Q000378:metabolism*
D008024:Ligands; D019275:Radiopharmaceuticals; D044302:Receptor, Serotonin, 5-HT1B; D015636:Magnesium Chloride; D006147:Guanine; D017371:8-Hydroxy-2-(di-n-propylamino)tetralin