“5-HT1R” or 5-HT1D sites? Evidence for 5-HT 1D binding sites in rabbit brain

Abstract

Radioligand binding studies were performed in membranes of rabbit whole brain and striatum using the novel iodinated radioligand for 5-hydroxytryptamine 5-HT1B and 5-HT1D sites, Serotonin-5-O-Carboxymethyl-Glycyl[125I]Tyrosinamide ([125I]GTI). [125I]GTI labelled a finite number of high affinity sites in rabbit brain membranes, Bmax = 191 +- 47 fmol/mg protein, pKD (-log mol/1) = 8.50 +- 0.13, n = 5. The pharmacological profile of [152I]GTI binding was fully comparable to that reported previously in human and other brain preparations known to possess 5-HT1D sites (using either [3H]5-HT or [125I]GTI) and displayed a characteristic rank order of affinity: 5-carboxamidotryptamine > 5-HT = dihydr..