Evidence for specific N-terminal galanin fragment binding sites in the rat brain.
The existence and widespread distribution of specific [125I]galanin-(1-15) fragment binding sites in the rat brain was demonstrated by using [125I]galanin-(1-15) as a radioligand in quantitative receptor autoradiographical studies. These binding sites were also present in several areas lacking or having very few [125I]galanin-(1-29) binding sites, such as the dorsal hippocampal formation, the neocortex and the neostriatum. [125I]Galanin-(1-15) binding sites showed a high selectivity for the fragment, since galanin-(1-15) could displace 80% of the binding whereas porcine galanin-(1-29) could only displace 30%. The binding was saturable with a Kd of 0.63 +/- 0.02 nM and a Bmax of 15.3 +/- 1.7 fmol/mg in sections from the dorsal hippocampal formation. Thus, a new type of galanin receptor selective for N-terminal galanin fragments may exist in the rat brain.
D000818:Animals; D001345:Autoradiography; D001665:Binding Sites; D001667:Binding, Competitive; D001921:Brain / Q000378:metabolism*; D019004:Galanin; D008297:Male; D009479:Neuropeptides / Q000378:metabolism*; D010446:Peptide Fragments / Q000378:metabolism*; D010455:Peptides / Q000378:metabolism*; D051381:Rats; D017207:Rats, Sprague-Dawley; D044088:Receptors, Galanin; D011964:Receptors, Gastrointestinal Hormone / Q000378:metabolism*
D009479:Neuropeptides; D010446:Peptide Fragments; D010455:Peptides; D044088:Receptors, Galanin; D011964:Receptors, Gastrointestinal Hormone; D019004:Galanin