GABAA and GABAB sites in bovine adrenal medulla membranes

✍ Scribed by E. Castro; M. J. Oset-Gasque; S. Cañadas; G. Gimenez; M. P. González

• Book ID: 102384444
• Publisher: John Wiley and Sons
• Year: 1988
• Tongue: English
• Weight: 440 KB
• Volume: 20
• Category: Article
• ISSN: 0360-4012
• DOI: 10.1002/jnr.490200213

✦ Synopsis

The effect of several ligands and Ca2+ ions on [3H]GABA binding to bovine adrenal medulla membranes was investigated. Without any blockade, the [3H]GABA bmding showed two components, one of low affinity (Kd = 139 2 22nMandB,, = 3.2 f 0.4pmoYmgprotein) and the other of high affinity (Kd = 41 2 6 nM and B, = 0.35 f 0.26 pmoYmg protein). Muscimol specifically blocked low-affinity sites, and (-)baclofen blocked high-athity components. Ca2' ions were strictly necessary for maximum binding to high-affiinty sites, whereas they did not significantly affect sites of the lower afl'inity. These results show that the bovine adrenal medulla has a GABAA receptor population of low affinity together with a GABAB receptor of high f l i n t y .